Extract Sample code into examples/api (#87280)

This extracts the sample code out from the API doc comments, and places them in separate files on disk, allowing running of the examples locally, testing them, and building of slightly larger examples.

dev/bots/test.dart

@@ -408,15 +408,17 @@ Future<void> runForbiddenFromReleaseTests() async {
   );
 }
 
-/// Verifies that APK, and IPA (if on macOS) builds the examples apps
-/// without crashing. It does not actually launch the apps. That happens later
-/// in the devicelab. This is just a smoke-test. In particular, this will verify
-/// we can build when there are spaces in the path name for the Flutter SDK and
-/// target app.
+/// Verifies that APK, and IPA (if on macOS), and native desktop builds the
+/// examples apps without crashing. It does not actually launch the apps. That
+/// happens later in the devicelab. This is just a smoke-test. In particular,
+/// this will verify we can build when there are spaces in the path name for the
+/// Flutter SDK and target app.
 ///
 /// Also does some checking about types included in hello_world.
 Future<void> _runBuildTests() async {
-  final List<FileSystemEntity> exampleDirectories = Directory(path.join(flutterRoot, 'examples')).listSync()
+  final List<Directory> exampleDirectories = Directory(path.join(flutterRoot, 'examples')).listSync()
+    // API example builds will be tested in a separate shard.
+    .where((FileSystemEntity entity) => entity is Directory && path.basename(entity.path) != 'api').cast<Directory>().toList()
     ..add(Directory(path.join(flutterRoot, 'packages', 'integration_test', 'example')))
     ..add(Directory(path.join(flutterRoot, 'dev', 'integration_tests', 'android_semantics_testing')))
     ..add(Directory(path.join(flutterRoot, 'dev', 'integration_tests', 'android_views')))
@@ -430,7 +432,7 @@ Future<void> _runBuildTests() async {
   // The tests are randomly distributed into subshards so as to get a uniform
   // distribution of costs, but the seed is fixed so that issues are reproducible.
   final List<ShardRunner> tests = <ShardRunner>[
-    for (final FileSystemEntity exampleDirectory in exampleDirectories)
+    for (final Directory exampleDirectory in exampleDirectories)
       () => _runExampleProjectBuildTests(exampleDirectory),
     ...<ShardRunner>[
       // Web compilation tests.
@@ -450,7 +452,7 @@ Future<void> _runBuildTests() async {
   await _runShardRunnerIndexOfTotalSubshard(tests);
 }
 
-Future<void> _runExampleProjectBuildTests(FileSystemEntity exampleDirectory) async {
+Future<void> _runExampleProjectBuildTests(Directory exampleDirectory, [File? mainFile]) async {
   // Only verify caching with flutter gallery.
   final bool verifyCaching = exampleDirectory.path.contains('flutter_gallery');
   if (exampleDirectory is! Directory) {
@@ -458,9 +460,10 @@ Future<void> _runExampleProjectBuildTests(FileSystemEntity exampleDirectory) asy
   }
   final String examplePath = exampleDirectory.path;
   final bool hasNullSafety = File(path.join(examplePath, 'null_safety')).existsSync();
-  final List<String> additionalArgs = hasNullSafety
-    ? <String>['--no-sound-null-safety']
-    : <String>[];
+  final List<String> additionalArgs = <String>[
+    if (hasNullSafety) '--no-sound-null-safety',
+    if (mainFile != null) path.relative(mainFile.path, from: exampleDirectory.absolute.path),
+  ];
   if (Directory(path.join(examplePath, 'android')).existsSync()) {
     await _flutterBuildApk(examplePath, release: false, additionalArgs: additionalArgs, verifyCaching: verifyCaching);
     await _flutterBuildApk(examplePath, release: true, additionalArgs: additionalArgs, verifyCaching: verifyCaching);

examples/api/.metadata

+# This file tracks properties of this Flutter project.
+# Used by Flutter tool to assess capabilities and perform upgrades etc.
+#
+# This file should be version controlled and should not be manually edited.
+
+version:
+  revision: e91847fe7cadcc293e6b75ec614dfad5097d9de8
+  channel: extract_samples
+
+project_type: app

examples/api/README.md

+# API Example Code
+
+This directory contains the API sample code that is referenced from the
+API documentation in each class.
+
+They can be run individually by just specifying the path to the example on the
+command line (or in the run configuration of an IDE).
+
+For example, to run, in Chrome, the first example from the `Curve2D` class, you
+would run it like so, from this [api](.) directory:
+
+```
+% flutter run -d chrome lib/animation/curves/curve2_d.0.dart
+```
+
+These same examples are available on the API docs site. For instance, the
+example above is available on [this
+page](https://api.flutter.dev/flutter/animation/Curve2D-class.html#animation.Curve2D.1).
+Most of them are available as interactive examples in Dartpad, but some just
+don't make sense on the web, and so are available as standalone examples that
+can be run here.
+
+## Naming
+
+The naming scheme for the files is similar to the hierarchy under
+[packages/flutter/lib/src](../../packages/flutter/lib/src), except that the
+files are represented as directories, and each sample in each file as a separate
+file in that directory. So, for the example above, the examples are from the
+[packages/flutter/lib/src/animation/curves.dart](../../packages/flutter/lib/src/animation/curves.dart)
+file, the `Curve2D` class, and the first sample (hence the index "0") for that
+symbol resides in the
+[lib/animation/curves/curve2_d.0.dart](lib/animation/curves/curve2_d.0.dart)
+file.
+
+## Authoring
+
+When authoring these examples, place a block like so in the Dartdoc
+documentation for the symbol you would like to attach it to. Here's what it
+might look like if you wanted to add a new example to the `Curve2D` class. First
+add the stub to the symbol documentation:
+
+```dart
+/// {@tool dartpad --template=material_scaffold}
+/// Write a description of the example here. This description will appear in the
+/// API web documentation to introduce the example.
+///
+/// ```dart
+/// // These are the sections you want to fill out in the template.
+/// // They will be transferred to the example file when you extract it.
+/// ```
+/// {@end-tool}
+```
+
+Then install the `extract_sample` command with:
+
+```
+% pub global activate snippets
+```
+
+And run the `extract_sample` command from the Flutter repo dir:
+
+```
+$ pub global run extract_sample packages/flutter/lib/src/animation/curves.dart
+```
+
+This will create a new file in the `examples/api` directory, in this case it
+would create `examples/api/lib/animation/curves/curve2_d.1.dart`

examples/api/android/.gitignore

+gradle-wrapper.jar
+/.gradle
+/captures/
+/gradlew
+/gradlew.bat
+/local.properties
+GeneratedPluginRegistrant.java
+
+# Remember to never publicly share your keystore.
+# See https://flutter.dev/docs/deployment/android#reference-the-keystore-from-the-app
+key.properties
+**/*.keystore
+**/*.jks

examples/api/android/app/build.gradle

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+def localProperties = new Properties()
+def localPropertiesFile = rootProject.file('local.properties')
+if (localPropertiesFile.exists()) {
+    localPropertiesFile.withReader('UTF-8') { reader ->
+        localProperties.load(reader)
+    }
+}
+
+def flutterRoot = localProperties.getProperty('flutter.sdk')
+if (flutterRoot == null) {
+    throw new GradleException("Flutter SDK not found. Define location with flutter.sdk in the local.properties file.")
+}
+
+def flutterVersionCode = localProperties.getProperty('flutter.versionCode')
+if (flutterVersionCode == null) {
+    flutterVersionCode = '1'
+}
+
+def flutterVersionName = localProperties.getProperty('flutter.versionName')
+if (flutterVersionName == null) {
+    flutterVersionName = '1.0'
+}
+
+apply plugin: 'com.android.application'
+apply plugin: 'kotlin-android'
+apply from: "$flutterRoot/packages/flutter_tools/gradle/flutter.gradle"
+
+android {
+    compileSdkVersion 30
+
+    compileOptions {
+        sourceCompatibility JavaVersion.VERSION_1_8
+        targetCompatibility JavaVersion.VERSION_1_8
+    }
+
+    kotlinOptions {
+        jvmTarget = '1.8'
+    }
+
+    sourceSets {
+        main.java.srcDirs += 'src/main/kotlin'
+    }
+
+    defaultConfig {
+        // TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html).
+        applicationId "dev.flutter.dartpad_curve2_d_0"
+        minSdkVersion 16
+        targetSdkVersion 30
+        versionCode flutterVersionCode.toInteger()
+        versionName flutterVersionName
+    }
+
+    buildTypes {
+        release {
+            // TODO: Add your own signing config for the release build.
+            // Signing with the debug keys for now, so `flutter run --release` works.
+            signingConfig signingConfigs.debug
+        }
+    }
+}
+
+flutter {
+    source '../..'
+}
+
+dependencies {
+    implementation "org.jetbrains.kotlin:kotlin-stdlib-jdk7:$kotlin_version"
+}

examples/api/android/app/src/debug/AndroidManifest.xml

+<!-- Copyright 2014 The Flutter Authors. All rights reserved.
+Use of this source code is governed by a BSD-style license that can be
+found in the LICENSE file. -->
+
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="dev.flutter.dartpad_curve2_d_0">
+    <!-- Flutter needs it to communicate with the running application
+         to allow setting breakpoints, to provide hot reload, etc.
+    -->
+    <uses-permission android:name="android.permission.INTERNET"/>
+</manifest>

examples/api/android/app/src/main/AndroidManifest.xml

+<!-- Copyright 2014 The Flutter Authors. All rights reserved.
+Use of this source code is governed by a BSD-style license that can be
+found in the LICENSE file. -->
+
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="dev.flutter.dartpad_curve2_d_0">
+   <application
+        android:label="dartpad_curve2_d_0"
+        android:icon="@mipmap/ic_launcher">
+        <activity
+            android:name=".MainActivity"
+            android:launchMode="singleTop"
+            android:theme="@style/LaunchTheme"
+            android:configChanges="orientation|keyboardHidden|keyboard|screenSize|smallestScreenSize|locale|layoutDirection|fontScale|screenLayout|density|uiMode"
+            android:hardwareAccelerated="true"
+            android:windowSoftInputMode="adjustResize">
+            <!-- Specifies an Android theme to apply to this Activity as soon as
+                 the Android process has started. This theme is visible to the user
+                 while the Flutter UI initializes. After that, this theme continues
+                 to determine the Window background behind the Flutter UI. -->
+            <meta-data
+              android:name="io.flutter.embedding.android.NormalTheme"
+              android:resource="@style/NormalTheme"
+              />
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN"/>
+                <category android:name="android.intent.category.LAUNCHER"/>
+            </intent-filter>
+        </activity>
+        <!-- Don't delete the meta-data below.
+             This is used by the Flutter tool to generate GeneratedPluginRegistrant.java -->
+        <meta-data
+            android:name="flutterEmbedding"
+            android:value="2" />
+    </application>
+</manifest>

examples/api/android/app/src/main/kotlin/dev/flutter/dartpad_curve2_d_0/MainActivity.kt

+package dev.flutter.dartpad_curve2_d_0
+
+import io.flutter.embedding.android.FlutterActivity
+
+class MainActivity: FlutterActivity() {
+}

examples/api/android/app/src/main/res/color/fab_ripple_color.xml

+<!-- Copyright 2014 The Flutter Authors. All rights reserved.
+Use of this source code is governed by a BSD-style license that can be
+found in the LICENSE file. -->
+
+<selector xmlns:android="http://schemas.android.com/apk/res/android">
+  <item android:state_pressed="true" android:color="@color/grey" />
+  <item android:state_focused="true" android:color="@color/grey" />
+  <item android:color="@color/white"/>
+</selector>

examples/api/android/app/src/main/res/drawable/ic_add_black_24dp.xml

+<!-- Copyright 2014 The Flutter Authors. All rights reserved.
+Use of this source code is governed by a BSD-style license that can be
+found in the LICENSE file. -->
+
+<vector xmlns:android="http://schemas.android.com/apk/res/android"
+        android:width="24dp"
+        android:height="24dp"
+        android:viewportWidth="24.0"
+        android:viewportHeight="24.0">
+    <path
+        android:fillColor="#FF000000"
+        android:pathData="M19,13h-6v6h-2v-6H5v-2h6V5h2v6h6v2z"/>
+</vector>

examples/api/android/app/src/main/res/layout/flutter_view_layout.xml

+<!-- Copyright 2014 The Flutter Authors. All rights reserved.
+Use of this source code is governed by a BSD-style license that can be
+found in the LICENSE file. -->
+
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+  xmlns:app="http://schemas.android.com/apk/res-auto"
+  android:orientation="vertical"
+  android:layout_width="match_parent"
+  android:layout_height="match_parent"
+  >
+
+  <io.flutter.embedding.android.FlutterView
+    android:id="@+id/flutter_view"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:layout_weight="1"
+    />
+
+  <androidx.coordinatorlayout.widget.CoordinatorLayout
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:layout_weight="1"
+    android:background="@color/grey"
+    >
+
+    <LinearLayout
+      android:layout_width="match_parent"
+      android:layout_height="match_parent"
+      android:orientation="vertical"
+      >
+
+      <TextView
+        android:id="@+id/button_tap"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:text="@string/button_tap"
+        android:layout_weight="1"
+        android:gravity="center"
+        android:textSize="@dimen/font_size"
+        />
+
+      <TextView
+        android:layout_width="wrap_content"
+        android:layout_height="wrap_content"
+        android:text="@string/android"
+        android:layout_margin="@dimen/edge_margin"
+        android:textSize="@dimen/platform_label_font_size"
+        android:background="@color/grey"
+        />
+
+    </LinearLayout>
+
+    <com.google.android.material.floatingactionbutton.FloatingActionButton
+      android:id="@+id/button"
+      android:layout_width="wrap_content"
+      android:layout_height="wrap_content"
+      android:layout_gravity="bottom|right"
+      android:elevation="@dimen/fab_elevation_resting"
+      app:pressedTranslationZ="@dimen/fab_elevation_pressed"
+      android:layout_margin="@dimen/edge_margin"
+      android:src="@drawable/ic_add_black_24dp"
+      android:clickable="true"
+      app:rippleColor="@color/grey"
+      app:fabSize="normal"
+      app:backgroundTint="@color/white"
+      />
+
+  </androidx.coordinatorlayout.widget.CoordinatorLayout>
+
+</LinearLayout>

examples/api/android/app/src/main/res/values/colors.xml

+<!-- Copyright 2014 The Flutter Authors. All rights reserved.
+Use of this source code is governed by a BSD-style license that can be
+found in the LICENSE file. -->
+
+<resources>
+  <item name="grey" type="color">#9E9E9E</item>
+  <item name="white" type="color">#FFFFFF</item>
+</resources>

examples/api/android/app/src/main/res/values/dimens.xml

+<!-- Copyright 2014 The Flutter Authors. All rights reserved.
+Use of this source code is governed by a BSD-style license that can be
+found in the LICENSE file. -->
+
+<resources>
+  <dimen name="edge_margin">16dp</dimen>
+  <dimen name="fab_elevation_resting">6dp</dimen>
+  <dimen name="fab_elevation_pressed">12dp</dimen>
+  <dimen name="font_size">17sp</dimen>
+  <dimen name="platform_label_font_size">30sp</dimen>
+</resources>

examples/api/android/app/src/main/res/values/strings.xml

+<!-- Copyright 2014 The Flutter Authors. All rights reserved.
+Use of this source code is governed by a BSD-style license that can be
+found in the LICENSE file. -->
+
+<resources>
+  <string name="app_name">Flutter View</string>
+  <string name="title">Flutter Application</string>
+  <string name="button_tap">Flutter button tapped 0 times.</string>
+  <string name="android">Android</string>
+</resources>

examples/api/android/app/src/profile/AndroidManifest.xml

+<!-- Copyright 2014 The Flutter Authors. All rights reserved.
+Use of this source code is governed by a BSD-style license that can be
+found in the LICENSE file. -->
+
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="dev.flutter.dartpad_curve2_d_0">
+    <!-- Flutter needs it to communicate with the running application
+         to allow setting breakpoints, to provide hot reload, etc.
+    -->
+    <uses-permission android:name="android.permission.INTERNET"/>
+</manifest>

examples/api/android/build.gradle

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+buildscript {
+    ext.kotlin_version = '1.3.50'
+    repositories {
+        google()
+        mavenCentral()
+    }
+
+    dependencies {
+        classpath 'com.android.tools.build:gradle:4.1.0'
+        classpath "org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version"
+    }
+}
+
+allprojects {
+    repositories {
+        google()
+        mavenCentral()
+    }
+}
+
+rootProject.buildDir = '../build'
+subprojects {
+    project.buildDir = "${rootProject.buildDir}/${project.name}"
+    project.evaluationDependsOn(':app')
+}
+
+task clean(type: Delete) {
+    delete rootProject.buildDir
+}

examples/api/android/gradle.properties

+org.gradle.jvmargs=-Xmx1536M
+android.useAndroidX=true
+android.enableJetifier=true

examples/api/android/gradle/wrapper/gradle-wrapper.properties

+#Fri Jun 23 08:50:38 CEST 2017
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-6.7-all.zip

examples/api/android/settings.gradle

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+include ':app'
+
+def localPropertiesFile = new File(rootProject.projectDir, "local.properties")
+def properties = new Properties()
+
+assert localPropertiesFile.exists()
+localPropertiesFile.withReader("UTF-8") { reader -> properties.load(reader) }
+
+def flutterSdkPath = properties.getProperty("flutter.sdk")
+assert flutterSdkPath != null, "flutter.sdk not set in local.properties"
+apply from: "$flutterSdkPath/packages/flutter_tools/gradle/app_plugin_loader.gradle"

examples/api/ios/.gitignore

+*.mode1v3
+*.mode2v3
+*.moved-aside
+*.pbxuser
+*.perspectivev3
+**/*sync/
+.sconsign.dblite
+.tags*
+**/.vagrant/
+**/DerivedData/
+Icon?
+**/Pods/
+**/.symlinks/
+profile
+xcuserdata
+**/.generated/
+Flutter/App.framework
+Flutter/Flutter.framework
+Flutter/Flutter.podspec
+Flutter/Generated.xcconfig
+Flutter/ephemeral/
+Flutter/app.flx
+Flutter/app.zip
+Flutter/flutter_assets/
+Flutter/flutter_export_environment.sh
+ServiceDefinitions.json
+Runner/GeneratedPluginRegistrant.*
+
+# Exceptions to above rules.
+!default.mode1v3
+!default.mode2v3
+!default.pbxuser
+!default.perspectivev3

examples/api/ios/Flutter/AppFrameworkInfo.plist

+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+  <key>CFBundleDevelopmentRegion</key>
+  <string>en</string>
+  <key>CFBundleExecutable</key>
+  <string>App</string>
+  <key>CFBundleIdentifier</key>
+  <string>io.flutter.flutter.app</string>
+  <key>CFBundleInfoDictionaryVersion</key>
+  <string>6.0</string>
+  <key>CFBundleName</key>
+  <string>App</string>
+  <key>CFBundlePackageType</key>
+  <string>FMWK</string>
+  <key>CFBundleShortVersionString</key>
+  <string>1.0</string>
+  <key>CFBundleSignature</key>
+  <string>????</string>
+  <key>CFBundleVersion</key>
+  <string>1.0</string>
+  <key>MinimumOSVersion</key>
+  <string>9.0</string>
+</dict>
+</plist>

examples/api/ios/Flutter/Debug.xcconfig

+#include "Generated.xcconfig"

examples/api/ios/Flutter/Release.xcconfig

+#include "Generated.xcconfig"

examples/api/ios/Runner.xcodeproj/project.xcworkspace/contents.xcworkspacedata

+<?xml version="1.0" encoding="UTF-8"?>
+<Workspace
+   version = "1.0">
+   <FileRef
+      location = "self:">
+   </FileRef>
+</Workspace>

examples/api/ios/Runner.xcodeproj/project.xcworkspace/xcshareddata/IDEWorkspaceChecks.plist

+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>IDEDidComputeMac32BitWarning</key>
+	<true/>
+</dict>
+</plist>

examples/api/ios/Runner.xcodeproj/project.xcworkspace/xcshareddata/WorkspaceSettings.xcsettings

+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>PreviewsEnabled</key>
+	<false/>
+</dict>
+</plist>

examples/api/ios/Runner.xcodeproj/xcshareddata/xcschemes/Runner.xcscheme

+<?xml version="1.0" encoding="UTF-8"?>
+<Scheme
+   LastUpgradeVersion = "1020"
+   version = "1.3">
+   <BuildAction
+      parallelizeBuildables = "YES"
+      buildImplicitDependencies = "YES">
+      <BuildActionEntries>
+         <BuildActionEntry
+            buildForTesting = "YES"
+            buildForRunning = "YES"
+            buildForProfiling = "YES"
+            buildForArchiving = "YES"
+            buildForAnalyzing = "YES">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "97C146ED1CF9000F007C117D"
+               BuildableName = "Runner.app"
+               BlueprintName = "Runner"
+               ReferencedContainer = "container:Runner.xcodeproj">
+            </BuildableReference>
+         </BuildActionEntry>
+      </BuildActionEntries>
+   </BuildAction>
+   <TestAction
+      buildConfiguration = "Debug"
+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      shouldUseLaunchSchemeArgsEnv = "YES">
+      <Testables>
+      </Testables>
+      <MacroExpansion>
+         <BuildableReference
+            BuildableIdentifier = "primary"
+            BlueprintIdentifier = "97C146ED1CF9000F007C117D"
+            BuildableName = "Runner.app"
+            BlueprintName = "Runner"
+            ReferencedContainer = "container:Runner.xcodeproj">
+         </BuildableReference>
+      </MacroExpansion>
+      <AdditionalOptions>
+      </AdditionalOptions>
+   </TestAction>
+   <LaunchAction
+      buildConfiguration = "Debug"
+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      launchStyle = "0"
+      useCustomWorkingDirectory = "NO"
+      ignoresPersistentStateOnLaunch = "NO"
+      debugDocumentVersioning = "YES"
+      debugServiceExtension = "internal"
+      allowLocationSimulation = "YES">
+      <BuildableProductRunnable
+         runnableDebuggingMode = "0">
+         <BuildableReference
+            BuildableIdentifier = "primary"
+            BlueprintIdentifier = "97C146ED1CF9000F007C117D"
+            BuildableName = "Runner.app"
+            BlueprintName = "Runner"
+            ReferencedContainer = "container:Runner.xcodeproj">
+         </BuildableReference>
+      </BuildableProductRunnable>
+      <AdditionalOptions>
+      </AdditionalOptions>
+   </LaunchAction>
+   <ProfileAction
+      buildConfiguration = "Profile"
+      shouldUseLaunchSchemeArgsEnv = "YES"
+      savedToolIdentifier = ""
+      useCustomWorkingDirectory = "NO"
+      debugDocumentVersioning = "YES">
+      <BuildableProductRunnable
+         runnableDebuggingMode = "0">
+         <BuildableReference
+            BuildableIdentifier = "primary"
+            BlueprintIdentifier = "97C146ED1CF9000F007C117D"
+            BuildableName = "Runner.app"
+            BlueprintName = "Runner"
+            ReferencedContainer = "container:Runner.xcodeproj">
+         </BuildableReference>
+      </BuildableProductRunnable>
+   </ProfileAction>
+   <AnalyzeAction
+      buildConfiguration = "Debug">
+   </AnalyzeAction>
+   <ArchiveAction
+      buildConfiguration = "Release"
+      revealArchiveInOrganizer = "YES">
+   </ArchiveAction>
+</Scheme>

examples/api/ios/Runner.xcworkspace/contents.xcworkspacedata

+<?xml version="1.0" encoding="UTF-8"?>
+<Workspace
+   version = "1.0">
+   <FileRef
+      location = "group:Runner.xcodeproj">
+   </FileRef>
+</Workspace>

examples/api/ios/Runner.xcworkspace/xcshareddata/IDEWorkspaceChecks.plist

+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>IDEDidComputeMac32BitWarning</key>
+	<true/>
+</dict>
+</plist>

examples/api/ios/Runner.xcworkspace/xcshareddata/WorkspaceSettings.xcsettings

+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>PreviewsEnabled</key>
+	<false/>
+</dict>
+</plist>

examples/api/ios/Runner/AppDelegate.swift

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import UIKit
+import Flutter
+
+@UIApplicationMain
+@objc class AppDelegate: FlutterAppDelegate {
+  override func application(
+    _ application: UIApplication,
+    didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
+  ) -> Bool {
+    GeneratedPluginRegistrant.register(with: self)
+    return super.application(application, didFinishLaunchingWithOptions: launchOptions)
+  }
+}

examples/api/ios/Runner/Assets.xcassets/AppIcon.appiconset/Contents.json

+{
+  "images" : [
+    {
+      "idiom" : "iphone",
+      "size" : "20x20",
+      "scale" : "2x"
+    },
+    {
+      "idiom" : "iphone",
+      "size" : "20x20",
+      "scale" : "3x"
+    },
+    {
+      "size" : "29x29",
+      "idiom" : "iphone",
+      "filename" : "Icon-App-29x29@1x.png",
+      "scale" : "1x"
+    },
+    {
+      "size" : "29x29",
+      "idiom" : "iphone",
+      "filename" : "Icon-App-29x29@2x.png",
+      "scale" : "2x"
+    },
+    {
+      "size" : "29x29",
+      "idiom" : "iphone",
+      "filename" : "Icon-App-29x29@3x.png",
+      "scale" : "3x"
+    },
+    {
+      "size" : "40x40",
+      "idiom" : "iphone",
+      "filename" : "Icon-App-40x40@2x.png",
+      "scale" : "2x"
+    },
+    {
+      "size" : "40x40",
+      "idiom" : "iphone",
+      "filename" : "Icon-App-40x40@3x.png",
+      "scale" : "3x"
+    },
+    {
+      "size" : "60x60",
+      "idiom" : "iphone",
+      "filename" : "Icon-App-60x60@2x.png",
+      "scale" : "2x"
+    },
+    {
+      "size" : "60x60",
+      "idiom" : "iphone",
+      "filename" : "Icon-App-60x60@3x.png",
+      "scale" : "3x"
+    },
+    {
+      "idiom" : "ipad",
+      "size" : "20x20",
+      "scale" : "1x"
+    },
+    {
+      "idiom" : "ipad",
+      "size" : "20x20",
+      "scale" : "2x"
+    },
+    {
+      "size" : "29x29",
+      "idiom" : "ipad",
+      "filename" : "Icon-App-29x29@1x.png",
+      "scale" : "1x"
+    },
+    {
+      "size" : "29x29",
+      "idiom" : "ipad",
+      "filename" : "Icon-App-29x29@2x.png",
+      "scale" : "2x"
+    },
+    {
+      "size" : "40x40",
+      "idiom" : "ipad",
+      "filename" : "Icon-App-40x40@1x.png",
+      "scale" : "1x"
+    },
+    {
+      "size" : "40x40",
+      "idiom" : "ipad",
+      "filename" : "Icon-App-40x40@2x.png",
+      "scale" : "2x"
+    },
+    {
+      "size" : "76x76",
+      "idiom" : "ipad",
+      "filename" : "Icon-App-76x76@1x.png",
+      "scale" : "1x"
+    },
+    {
+      "size" : "76x76",
+      "idiom" : "ipad",
+      "filename" : "Icon-App-76x76@2x.png",
+      "scale" : "2x"
+    },
+    {
+      "size" : "83.5x83.5",
+      "idiom" : "ipad",
+      "filename" : "Icon-App-83.5x83.5@2x.png",
+      "scale" : "2x"
+    },
+    {
+      "size" : "40x40",
+      "idiom" : "iphone",
+      "filename" : "Icon-App-40x40@1x.png",
+      "scale" : "1x"
+    },
+    {
+      "size" : "60x60",
+      "idiom" : "iphone",
+      "filename" : "Icon-App-60x60@1x.png",
+      "scale" : "1x"
+    },
+    {
+      "size" : "76x76",
+      "idiom" : "ipad",
+      "filename" : "Icon-App-76x76@3x.png",
+      "scale" : "3x"
+    }
+  ],
+  "info" : {
+    "version" : 1,
+    "author" : "xcode"
+  }
+}
\ No newline at end of file

examples/api/ios/Runner/Base.lproj/LaunchScreen.storyboard

+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<document type="com.apple.InterfaceBuilder3.CocoaTouch.Storyboard.XIB" version="3.0" toolsVersion="12121" systemVersion="16G29" targetRuntime="iOS.CocoaTouch" propertyAccessControl="none" useAutolayout="YES" launchScreen="YES" colorMatched="YES" initialViewController="01J-lp-oVM">
+    <dependencies>
+        <deployment identifier="iOS"/>
+        <plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="12089"/>
+    </dependencies>
+    <scenes>
+        <!--View Controller-->
+        <scene sceneID="EHf-IW-A2E">
+            <objects>
+                <viewController id="01J-lp-oVM" sceneMemberID="viewController">
+                    <layoutGuides>
+                        <viewControllerLayoutGuide type="top" id="Ydg-fD-yQy"/>
+                        <viewControllerLayoutGuide type="bottom" id="xbc-2k-c8Z"/>
+                    </layoutGuides>
+                    <view key="view" contentMode="scaleToFill" id="Ze5-6b-2t3">
+                        <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
+                        <subviews>
+                            <imageView opaque="NO" clipsSubviews="YES" multipleTouchEnabled="YES" contentMode="center" image="LaunchImage" translatesAutoresizingMaskIntoConstraints="NO" id="YRO-k0-Ey4">
+                            </imageView>
+                        </subviews>
+                        <color key="backgroundColor" red="1" green="1" blue="1" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
+                        <constraints>
+                            <constraint firstItem="YRO-k0-Ey4" firstAttribute="centerX" secondItem="Ze5-6b-2t3" secondAttribute="centerX" id="1a2-6s-vTC"/>
+                            <constraint firstItem="YRO-k0-Ey4" firstAttribute="centerY" secondItem="Ze5-6b-2t3" secondAttribute="centerY" id="4X2-HB-R7a"/>
+                        </constraints>
+                    </view>
+                </viewController>
+                <placeholder placeholderIdentifier="IBFirstResponder" id="iYj-Kq-Ea1" userLabel="First Responder" sceneMemberID="firstResponder"/>
+            </objects>
+            <point key="canvasLocation" x="53" y="375"/>
+        </scene>
+    </scenes>
+    <resources>
+        <image name="LaunchImage" width="168" height="185"/>
+    </resources>
+</document>

examples/api/ios/Runner/Base.lproj/Main.storyboard

+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<document type="com.apple.InterfaceBuilder3.CocoaTouch.Storyboard.XIB" version="3.0" toolsVersion="10117" systemVersion="15F34" targetRuntime="iOS.CocoaTouch" propertyAccessControl="none" useAutolayout="YES" useTraitCollections="YES" initialViewController="BYZ-38-t0r">
+    <dependencies>
+        <deployment identifier="iOS"/>
+        <plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="10085"/>
+    </dependencies>
+    <scenes>
+        <!--Flutter View Controller-->
+        <scene sceneID="tne-QT-ifu">
+            <objects>
+                <viewController id="BYZ-38-t0r" customClass="FlutterViewController" sceneMemberID="viewController">
+                    <layoutGuides>
+                        <viewControllerLayoutGuide type="top" id="y3c-jy-aDJ"/>
+                        <viewControllerLayoutGuide type="bottom" id="wfy-db-euE"/>
+                    </layoutGuides>
+                    <view key="view" contentMode="scaleToFill" id="8bC-Xf-vdC">
+                        <rect key="frame" x="0.0" y="0.0" width="600" height="600"/>
+                        <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
+                        <color key="backgroundColor" white="1" alpha="1" colorSpace="custom" customColorSpace="calibratedWhite"/>
+                    </view>
+                </viewController>
+                <placeholder placeholderIdentifier="IBFirstResponder" id="dkx-z0-nzr" sceneMemberID="firstResponder"/>
+            </objects>
+        </scene>
+    </scenes>
+</document>

examples/api/ios/Runner/Info.plist

+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>CFBundleDevelopmentRegion</key>
+	<string>$(DEVELOPMENT_LANGUAGE)</string>
+	<key>CFBundleExecutable</key>
+	<string>$(EXECUTABLE_NAME)</string>
+	<key>CFBundleIdentifier</key>
+	<string>$(PRODUCT_BUNDLE_IDENTIFIER)</string>
+	<key>CFBundleInfoDictionaryVersion</key>
+	<string>6.0</string>
+	<key>CFBundleName</key>
+	<string>dartpad_curve2_d_0</string>
+	<key>CFBundlePackageType</key>
+	<string>APPL</string>
+	<key>CFBundleShortVersionString</key>
+	<string>$(FLUTTER_BUILD_NAME)</string>
+	<key>CFBundleSignature</key>
+	<string>????</string>
+	<key>CFBundleVersion</key>
+	<string>$(FLUTTER_BUILD_NUMBER)</string>
+	<key>LSRequiresIPhoneOS</key>
+	<true/>
+	<key>UILaunchStoryboardName</key>
+	<string>LaunchScreen</string>
+	<key>UIMainStoryboardFile</key>
+	<string>Main</string>
+	<key>UISupportedInterfaceOrientations</key>
+	<array>
+		<string>UIInterfaceOrientationPortrait</string>
+		<string>UIInterfaceOrientationLandscapeLeft</string>
+		<string>UIInterfaceOrientationLandscapeRight</string>
+	</array>
+	<key>UISupportedInterfaceOrientations~ipad</key>
+	<array>
+		<string>UIInterfaceOrientationPortrait</string>
+		<string>UIInterfaceOrientationPortraitUpsideDown</string>
+		<string>UIInterfaceOrientationLandscapeLeft</string>
+		<string>UIInterfaceOrientationLandscapeRight</string>
+	</array>
+	<key>UIViewControllerBasedStatusBarAppearance</key>
+	<false/>
+</dict>
+</plist>

examples/api/ios/Runner/Runner-Bridging-Header.h

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#import "GeneratedPluginRegistrant.h"

examples/api/lib/animation/curves/curve2_d.0.dart

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Template: dev/snippets/config/templates/stateless_widget_material.tmpl
+//
+// Comment lines marked with "▼▼▼" and "▲▲▲" are used for authoring
+// of samples, and may be ignored if you are just exploring the sample.
+
+// Flutter code sample for Curve2D
+//
+//***************************************************************************
+//* ▼▼▼▼▼▼▼▼ description ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+// This example shows how to use a [Curve2D] to modify the position of a widget
+// so that it can follow an arbitrary path.
+
+//* ▲▲▲▲▲▲▲▲ description ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//***************************************************************************
+
+import 'package:flutter/material.dart';
+
+void main() => runApp(const MyApp());
+
+/// This is the main application widget.
+class MyApp extends StatelessWidget {
+  const MyApp({Key? key}) : super(key: key);
+
+  static const String _title = 'Flutter Code Sample';
+
+  @override
+  Widget build(BuildContext context) {
+    return const MaterialApp(
+      title: _title,
+      home: MyStatelessWidget(),
+    );
+  }
+}
+
+//*****************************************************************************
+//* ▼▼▼▼▼▼▼▼ code-preamble ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+// This is the path that the child will follow. It's a CatmullRomSpline so
+// that the coordinates can be specified that it must pass through. If the
+// tension is set to 1.0, it will linearly interpolate between those points,
+// instead of interpolating smoothly.
+final CatmullRomSpline path = CatmullRomSpline(
+  const <Offset>[
+    Offset(0.05, 0.75),
+    Offset(0.18, 0.23),
+    Offset(0.32, 0.04),
+    Offset(0.73, 0.5),
+    Offset(0.42, 0.74),
+    Offset(0.73, 0.01),
+    Offset(0.93, 0.93),
+    Offset(0.05, 0.75),
+  ],
+  startHandle: const Offset(0.93, 0.93),
+  endHandle: const Offset(0.18, 0.23),
+  tension: 0.0,
+);
+
+class FollowCurve2D extends StatefulWidget {
+  const FollowCurve2D({
+    Key? key,
+    required this.path,
+    this.curve = Curves.easeInOut,
+    required this.child,
+    this.duration = const Duration(seconds: 1),
+  }) : super(key: key);
+
+  final Curve2D path;
+  final Curve curve;
+  final Duration duration;
+  final Widget child;
+
+  @override
+  State<FollowCurve2D> createState() => _FollowCurve2DState();
+}
+
+class _FollowCurve2DState extends State<FollowCurve2D>
+    with TickerProviderStateMixin {
+  // The animation controller for this animation.
+  late AnimationController controller;
+  // The animation that will be used to apply the widget's animation curve.
+  late Animation<double> animation;
+
+  @override
+  void initState() {
+    super.initState();
+    controller = AnimationController(duration: widget.duration, vsync: this);
+    animation = CurvedAnimation(parent: controller, curve: widget.curve);
+    // Have the controller repeat indefinitely.  If you want it to "bounce" back
+    // and forth, set the reverse parameter to true.
+    controller.repeat(reverse: false);
+    controller.addListener(() => setState(() {}));
+  }
+
+  @override
+  void dispose() {
+    super.dispose();
+    // Always have to dispose of animation controllers when done.
+    controller.dispose();
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    // Scale the path values to match the -1.0 to 1.0 domain of the Alignment widget.
+    final Offset position =
+        widget.path.transform(animation.value) * 2.0 - const Offset(1.0, 1.0);
+    return Align(
+      alignment: Alignment(position.dx, position.dy),
+      child: widget.child,
+    );
+  }
+}
+
+//* ▲▲▲▲▲▲▲▲ code-preamble ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//*****************************************************************************
+
+/// This is the stateless widget that the main application instantiates.
+class MyStatelessWidget extends StatelessWidget {
+  const MyStatelessWidget({Key? key}) : super(key: key);
+
+  @override
+//********************************************************************
+//* ▼▼▼▼▼▼▼▼ code ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+  Widget build(BuildContext context) {
+    return Container(
+      color: Colors.white,
+      alignment: Alignment.center,
+      child: FollowCurve2D(
+        path: path,
+        curve: Curves.easeInOut,
+        duration: const Duration(seconds: 3),
+        child: CircleAvatar(
+          backgroundColor: Colors.yellow,
+          child: DefaultTextStyle(
+            style: Theme.of(context).textTheme.headline6!,
+            child: const Text('B'), // Buzz, buzz!
+          ),
+        ),
+      ),
+    );
+  }
+
+//* ▲▲▲▲▲▲▲▲ code ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//********************************************************************
+
+}

examples/api/lib/cupertino/context_menu/cupertino_context_menu.0.dart

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Template: dev/snippets/config/templates/stateless_widget_material.tmpl
+//
+// Comment lines marked with "▼▼▼" and "▲▲▲" are used for authoring
+// of samples, and may be ignored if you are just exploring the sample.
+
+// Flutter code sample for CupertinoContextMenu
+//
+//***************************************************************************
+//* ▼▼▼▼▼▼▼▼ description ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+// This sample shows a very simple CupertinoContextMenu for an empty red
+// 100x100 Container. Simply long press on it to open.
+
+//* ▲▲▲▲▲▲▲▲ description ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//***************************************************************************
+
+//****************************************************************************
+//* ▼▼▼▼▼▼▼▼ code-imports ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+import 'package:flutter/cupertino.dart';
+
+//* ▲▲▲▲▲▲▲▲ code-imports ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//****************************************************************************
+
+import 'package:flutter/material.dart';
+
+void main() => runApp(const MyApp());
+
+/// This is the main application widget.
+class MyApp extends StatelessWidget {
+  const MyApp({Key? key}) : super(key: key);
+
+  static const String _title = 'Flutter Code Sample';
+
+  @override
+  Widget build(BuildContext context) {
+    return const MaterialApp(
+      title: _title,
+      home: MyStatelessWidget(),
+    );
+  }
+}
+
+/// This is the stateless widget that the main application instantiates.
+class MyStatelessWidget extends StatelessWidget {
+  const MyStatelessWidget({Key? key}) : super(key: key);
+
+  @override
+//********************************************************************
+//* ▼▼▼▼▼▼▼▼ code ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+  Widget build(BuildContext context) {
+    return Scaffold(
+      body: Center(
+        child: SizedBox(
+          width: 100,
+          height: 100,
+          child: CupertinoContextMenu(
+            child: Container(
+              color: Colors.red,
+            ),
+            actions: <Widget>[
+              CupertinoContextMenuAction(
+                child: const Text('Action one'),
+                onPressed: () {
+                  Navigator.pop(context);
+                },
+              ),
+              CupertinoContextMenuAction(
+                child: const Text('Action two'),
+                onPressed: () {
+                  Navigator.pop(context);
+                },
+              ),
+            ],
+          ),
+        ),
+      ),
+    );
+  }
+
+//* ▲▲▲▲▲▲▲▲ code ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//********************************************************************
+
+}

examples/api/lib/cupertino/nav_bar/cupertino_navigation_bar.0.dart

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Template: dev/snippets/config/templates/stateful_widget_cupertino.tmpl
+//
+// Comment lines marked with "▼▼▼" and "▲▲▲" are used for authoring
+// of samples, and may be ignored if you are just exploring the sample.
+
+// Flutter code sample for CupertinoNavigationBar
+//
+//***************************************************************************
+//* ▼▼▼▼▼▼▼▼ description ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+// This example shows a [CupertinoNavigationBar] placed in a [CupertinoPageScaffold].
+// Since [backgroundColor]'s opacity is not 1.0, there is a blur effect and
+// content slides underneath.
+
+//* ▲▲▲▲▲▲▲▲ description ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//***************************************************************************
+
+import 'package:flutter/cupertino.dart';
+
+void main() => runApp(const MyApp());
+
+/// This is the main application widget.
+class MyApp extends StatelessWidget {
+  const MyApp({Key? key}) : super(key: key);
+
+  static const String _title = 'Flutter Code Sample';
+
+  @override
+  Widget build(BuildContext context) {
+    return const CupertinoApp(
+      title: _title,
+      home: MyStatefulWidget(),
+    );
+  }
+}
+
+/// This is the stateful widget that the main application instantiates.
+class MyStatefulWidget extends StatefulWidget {
+  const MyStatefulWidget({Key? key}) : super(key: key);
+
+  @override
+  State<MyStatefulWidget> createState() => _MyStatefulWidgetState();
+}
+
+/// This is the private State class that goes with MyStatefulWidget.
+class _MyStatefulWidgetState extends State<MyStatefulWidget> {
+//********************************************************************
+//* ▼▼▼▼▼▼▼▼ code ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+  @override
+  Widget build(BuildContext context) {
+    return CupertinoPageScaffold(
+      navigationBar: CupertinoNavigationBar(
+        // Try removing opacity to observe the lack of a blur effect and of sliding content.
+        backgroundColor: CupertinoColors.systemGrey.withOpacity(0.5),
+        middle: const Text('Sample Code'),
+      ),
+      child: Column(
+        children: <Widget>[
+          Container(height: 50, color: CupertinoColors.systemRed),
+          Container(height: 50, color: CupertinoColors.systemGreen),
+          Container(height: 50, color: CupertinoColors.systemBlue),
+          Container(height: 50, color: CupertinoColors.systemYellow),
+        ],
+      ),
+    );
+  }
+
+//* ▲▲▲▲▲▲▲▲ code ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//********************************************************************
+
+}

examples/api/lib/cupertino/page_scaffold/cupertino_page_scaffold.0.dart

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Template: dev/snippets/config/templates/stateful_widget_cupertino.tmpl
+//
+// Comment lines marked with "▼▼▼" and "▲▲▲" are used for authoring
+// of samples, and may be ignored if you are just exploring the sample.
+
+// Flutter code sample for CupertinoPageScaffold
+//
+//***************************************************************************
+//* ▼▼▼▼▼▼▼▼ description ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+// This example shows a [CupertinoPageScaffold] with a [ListView] as a [child].
+// The [CupertinoButton] is connected to a callback that increments a counter.
+// The [backgroundColor] can be changed.
+
+//* ▲▲▲▲▲▲▲▲ description ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//***************************************************************************
+
+import 'package:flutter/cupertino.dart';
+
+void main() => runApp(const MyApp());
+
+/// This is the main application widget.
+class MyApp extends StatelessWidget {
+  const MyApp({Key? key}) : super(key: key);
+
+  static const String _title = 'Flutter Code Sample';
+
+  @override
+  Widget build(BuildContext context) {
+    return const CupertinoApp(
+      title: _title,
+      home: MyStatefulWidget(),
+    );
+  }
+}
+
+/// This is the stateful widget that the main application instantiates.
+class MyStatefulWidget extends StatefulWidget {
+  const MyStatefulWidget({Key? key}) : super(key: key);
+
+  @override
+  State<MyStatefulWidget> createState() => _MyStatefulWidgetState();
+}
+
+/// This is the private State class that goes with MyStatefulWidget.
+class _MyStatefulWidgetState extends State<MyStatefulWidget> {
+//********************************************************************
+//* ▼▼▼▼▼▼▼▼ code ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+  int _count = 0;
+
+  @override
+  Widget build(BuildContext context) {
+    return CupertinoPageScaffold(
+      // Uncomment to change the background color
+      // backgroundColor: CupertinoColors.systemPink,
+      navigationBar: const CupertinoNavigationBar(
+        middle: Text('Sample Code'),
+      ),
+      child: ListView(
+        children: <Widget>[
+          CupertinoButton(
+            onPressed: () => setState(() => _count++),
+            child: const Icon(CupertinoIcons.add),
+          ),
+          Center(
+            child: Text('You have pressed the button $_count times.'),
+          ),
+        ],
+      ),
+    );
+  }
+
+//* ▲▲▲▲▲▲▲▲ code ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//********************************************************************
+
+}

examples/api/lib/cupertino/refresh/cupertino_sliver_refresh_control.0.dart

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Template: dev/snippets/config/templates/stateful_widget_cupertino.tmpl
+//
+// Comment lines marked with "▼▼▼" and "▲▲▲" are used for authoring
+// of samples, and may be ignored if you are just exploring the sample.
+
+// Flutter code sample for CupertinoSliverRefreshControl
+//
+//***************************************************************************
+//* ▼▼▼▼▼▼▼▼ description ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+// When the user scrolls past [refreshTriggerPullDistance],
+// this sample shows the default iOS pull to refresh indicator for 1 second and
+// adds a new item to the top of the list view.
+
+//* ▲▲▲▲▲▲▲▲ description ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//***************************************************************************
+
+import 'package:flutter/cupertino.dart';
+
+void main() => runApp(const MyApp());
+
+/// This is the main application widget.
+class MyApp extends StatelessWidget {
+  const MyApp({Key? key}) : super(key: key);
+
+  static const String _title = 'Flutter Code Sample';
+
+  @override
+  Widget build(BuildContext context) {
+    return const CupertinoApp(
+      title: _title,
+      home: MyStatefulWidget(),
+    );
+  }
+}
+
+/// This is the stateful widget that the main application instantiates.
+class MyStatefulWidget extends StatefulWidget {
+  const MyStatefulWidget({Key? key}) : super(key: key);
+
+  @override
+  State<MyStatefulWidget> createState() => _MyStatefulWidgetState();
+}
+
+/// This is the private State class that goes with MyStatefulWidget.
+class _MyStatefulWidgetState extends State<MyStatefulWidget> {
+//********************************************************************
+//* ▼▼▼▼▼▼▼▼ code ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+  List<Color> colors = <Color>[
+    CupertinoColors.systemYellow,
+    CupertinoColors.systemOrange,
+    CupertinoColors.systemPink
+  ];
+  List<Widget> items = <Widget>[
+    Container(color: CupertinoColors.systemPink, height: 100.0),
+    Container(color: CupertinoColors.systemOrange, height: 100.0),
+    Container(color: CupertinoColors.systemYellow, height: 100.0),
+  ];
+
+  @override
+  Widget build(BuildContext context) {
+    return CupertinoApp(
+        home: CupertinoPageScaffold(
+            child: CustomScrollView(
+      physics:
+          const BouncingScrollPhysics(parent: AlwaysScrollableScrollPhysics()),
+      slivers: <Widget>[
+        const CupertinoSliverNavigationBar(largeTitle: Text('Scroll down')),
+        CupertinoSliverRefreshControl(
+          refreshTriggerPullDistance: 100.0,
+          refreshIndicatorExtent: 60.0,
+          onRefresh: () async {
+            await Future<void>.delayed(const Duration(milliseconds: 1000));
+            setState(() {
+              items.insert(
+                  0, Container(color: colors[items.length % 3], height: 100.0));
+            });
+          },
+        ),
+        SliverList(
+          delegate: SliverChildBuilderDelegate(
+            (BuildContext context, int index) => items[index],
+            childCount: items.length,
+          ),
+        ),
+      ],
+    )));
+  }
+
+//* ▲▲▲▲▲▲▲▲ code ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//********************************************************************
+
+}

examples/api/lib/cupertino/route/show_cupertino_dialog.0.dart

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Template: dev/snippets/config/templates/stateless_widget_restoration_cupertino.tmpl
+//
+// Comment lines marked with "▼▼▼" and "▲▲▲" are used for authoring
+// of samples, and may be ignored if you are just exploring the sample.
+
+// Flutter code sample for showCupertinoDialog
+//
+//***************************************************************************
+//* ▼▼▼▼▼▼▼▼ description ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+// This sample demonstrates how to create a restorable Cupertino dialog. This is
+// accomplished by enabling state restoration by specifying
+// [CupertinoApp.restorationScopeId] and using [Navigator.restorablePush] to
+// push [CupertinoDialogRoute] when the [CupertinoButton] is tapped.
+//
+// {@macro flutter.widgets.RestorationManager}
+
+//* ▲▲▲▲▲▲▲▲ description ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//***************************************************************************
+
+import 'package:flutter/cupertino.dart';
+
+void main() => runApp(const MyApp());
+
+/// This is the main application widget.
+class MyApp extends StatelessWidget {
+  const MyApp({Key? key}) : super(key: key);
+
+  static const String _title = 'Flutter Code Sample';
+
+  @override
+  Widget build(BuildContext context) {
+    return const CupertinoApp(
+      restorationScopeId: 'app',
+      title: _title,
+      home: MyStatelessWidget(),
+    );
+  }
+}
+
+/// This is the stateless widget that the main application instantiates.
+class MyStatelessWidget extends StatelessWidget {
+  const MyStatelessWidget({Key? key}) : super(key: key);
+
+  @override
+//********************************************************************
+//* ▼▼▼▼▼▼▼▼ code ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+  Widget build(BuildContext context) {
+    return CupertinoPageScaffold(
+      navigationBar: const CupertinoNavigationBar(
+        middle: Text('Home'),
+      ),
+      child: Center(
+          child: CupertinoButton(
+        onPressed: () {
+          Navigator.of(context).restorablePush(_dialogBuilder);
+        },
+        child: const Text('Open Dialog'),
+      )),
+    );
+  }
+
+  static Route<Object?> _dialogBuilder(
+      BuildContext context, Object? arguments) {
+    return CupertinoDialogRoute<void>(
+      context: context,
+      builder: (BuildContext context) {
+        return const CupertinoAlertDialog(
+          title: Text('Title'),
+          content: Text('Content'),
+          actions: <Widget>[
+            CupertinoDialogAction(child: Text('Yes')),
+            CupertinoDialogAction(child: Text('No')),
+          ],
+        );
+      },
+    );
+  }
+
+//* ▲▲▲▲▲▲▲▲ code ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//********************************************************************
+
+}

examples/api/lib/cupertino/route/show_cupertino_modal_popup.0.dart

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Template: dev/snippets/config/templates/stateless_widget_restoration_cupertino.tmpl
+//
+// Comment lines marked with "▼▼▼" and "▲▲▲" are used for authoring
+// of samples, and may be ignored if you are just exploring the sample.
+
+// Flutter code sample for showCupertinoModalPopup
+//
+//***************************************************************************
+//* ▼▼▼▼▼▼▼▼ description ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+// This sample demonstrates how to create a restorable Cupertino modal route.
+// This is accomplished by enabling state restoration by specifying
+// [CupertinoApp.restorationScopeId] and using [Navigator.restorablePush] to
+// push [CupertinoModalPopupRoute] when the [CupertinoButton] is tapped.
+//
+// {@macro flutter.widgets.RestorationManager}
+
+//* ▲▲▲▲▲▲▲▲ description ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//***************************************************************************
+
+import 'package:flutter/cupertino.dart';
+
+void main() => runApp(const MyApp());
+
+/// This is the main application widget.
+class MyApp extends StatelessWidget {
+  const MyApp({Key? key}) : super(key: key);
+
+  static const String _title = 'Flutter Code Sample';
+
+  @override
+  Widget build(BuildContext context) {
+    return const CupertinoApp(
+      restorationScopeId: 'app',
+      title: _title,
+      home: MyStatelessWidget(),
+    );
+  }
+}
+
+/// This is the stateless widget that the main application instantiates.
+class MyStatelessWidget extends StatelessWidget {
+  const MyStatelessWidget({Key? key}) : super(key: key);
+
+  @override
+//********************************************************************
+//* ▼▼▼▼▼▼▼▼ code ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+  Widget build(BuildContext context) {
+    return CupertinoPageScaffold(
+      navigationBar: const CupertinoNavigationBar(
+        middle: Text('Home'),
+      ),
+      child: Center(
+          child: CupertinoButton(
+        onPressed: () {
+          Navigator.of(context).restorablePush(_modalBuilder);
+        },
+        child: const Text('Open Modal'),
+      )),
+    );
+  }
+
+  static Route<void> _modalBuilder(BuildContext context, Object? arguments) {
+    return CupertinoModalPopupRoute<void>(
+      builder: (BuildContext context) {
+        return CupertinoActionSheet(
+          title: const Text('Title'),
+          message: const Text('Message'),
+          actions: <CupertinoActionSheetAction>[
+            CupertinoActionSheetAction(
+              child: const Text('Action One'),
+              onPressed: () {
+                Navigator.pop(context);
+              },
+            ),
+            CupertinoActionSheetAction(
+              child: const Text('Action Two'),
+              onPressed: () {
+                Navigator.pop(context);
+              },
+            ),
+          ],
+        );
+      },
+    );
+  }
+
+//* ▲▲▲▲▲▲▲▲ code ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//********************************************************************
+
+}

examples/api/lib/cupertino/scrollbar/cupertino_scrollbar.0.dart

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Template: dev/snippets/config/templates/stateless_widget_scaffold.tmpl
+//
+// Comment lines marked with "▼▼▼" and "▲▲▲" are used for authoring
+// of samples, and may be ignored if you are just exploring the sample.
+
+// Flutter code sample for CupertinoScrollbar
+//
+//***************************************************************************
+//* ▼▼▼▼▼▼▼▼ description ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+// This sample shows a [CupertinoScrollbar] that fades in and out of view as scrolling occurs.
+// The scrollbar will fade into view as the user scrolls, and fade out when scrolling stops.
+// The `thickness` of the scrollbar will animate from 6 pixels to the `thicknessWhileDragging` of 10
+// when it is dragged by the user. The `radius` of the scrollbar thumb corners will animate from 34
+// to the `radiusWhileDragging` of 0 when the scrollbar is being dragged by the user.
+
+//* ▲▲▲▲▲▲▲▲ description ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//***************************************************************************
+
+//****************************************************************************
+//* ▼▼▼▼▼▼▼▼ code-imports ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+import 'package:flutter/cupertino.dart';
+
+//* ▲▲▲▲▲▲▲▲ code-imports ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//****************************************************************************
+
+import 'package:flutter/material.dart';
+
+void main() => runApp(const MyApp());
+
+/// This is the main application widget.
+class MyApp extends StatelessWidget {
+  const MyApp({Key? key}) : super(key: key);
+
+  static const String _title = 'Flutter Code Sample';
+
+  @override
+  Widget build(BuildContext context) {
+    return MaterialApp(
+      title: _title,
+      home: Scaffold(
+        appBar: AppBar(title: const Text(_title)),
+        body: const MyStatelessWidget(),
+      ),
+    );
+  }
+}
+
+/// This is the stateless widget that the main application instantiates.
+class MyStatelessWidget extends StatelessWidget {
+  const MyStatelessWidget({Key? key}) : super(key: key);
+
+  @override
+//********************************************************************
+//* ▼▼▼▼▼▼▼▼ code ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+  @override
+  Widget build(BuildContext context) {
+    return CupertinoScrollbar(
+      thickness: 6.0,
+      thicknessWhileDragging: 10.0,
+      radius: const Radius.circular(34.0),
+      radiusWhileDragging: Radius.zero,
+      child: ListView.builder(
+        itemCount: 120,
+        itemBuilder: (BuildContext context, int index) {
+          return Center(
+            child: Text('item $index'),
+          );
+        },
+      ),
+    );
+  }
+
+//* ▲▲▲▲▲▲▲▲ code ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//********************************************************************
+
+}

examples/api/lib/cupertino/scrollbar/cupertino_scrollbar.1.dart

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Template: dev/snippets/config/templates/stateful_widget_scaffold.tmpl
+//
+// Comment lines marked with "▼▼▼" and "▲▲▲" are used for authoring
+// of samples, and may be ignored if you are just exploring the sample.
+
+// Flutter code sample for CupertinoScrollbar
+//
+//***************************************************************************
+//* ▼▼▼▼▼▼▼▼ description ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+// When `isAlwaysShown` is true, the scrollbar thumb will remain visible without the
+// fade animation. This requires that a [ScrollController] is provided to controller,
+// or that the [PrimaryScrollController] is available.
+
+//* ▲▲▲▲▲▲▲▲ description ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//***************************************************************************
+
+//****************************************************************************
+//* ▼▼▼▼▼▼▼▼ code-imports ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+import 'package:flutter/cupertino.dart';
+
+//* ▲▲▲▲▲▲▲▲ code-imports ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//****************************************************************************
+
+import 'package:flutter/material.dart';
+
+void main() => runApp(const MyApp());
+
+/// This is the main application widget.
+class MyApp extends StatelessWidget {
+  const MyApp({Key? key}) : super(key: key);
+
+  static const String _title = 'Flutter Code Sample';
+
+  @override
+  Widget build(BuildContext context) {
+    return MaterialApp(
+      title: _title,
+      home: Scaffold(
+        appBar: AppBar(title: const Text(_title)),
+        body: const MyStatefulWidget(),
+      ),
+    );
+  }
+}
+
+/// This is the stateful widget that the main application instantiates.
+class MyStatefulWidget extends StatefulWidget {
+  const MyStatefulWidget({Key? key}) : super(key: key);
+
+  @override
+  State<MyStatefulWidget> createState() => _MyStatefulWidgetState();
+}
+
+/// This is the private State class that goes with MyStatefulWidget.
+class _MyStatefulWidgetState extends State<MyStatefulWidget> {
+//********************************************************************
+//* ▼▼▼▼▼▼▼▼ code ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+  final ScrollController _controllerOne = ScrollController();
+
+  @override
+  Widget build(BuildContext context) {
+    return CupertinoScrollbar(
+      thickness: 6.0,
+      thicknessWhileDragging: 10.0,
+      radius: const Radius.circular(34.0),
+      radiusWhileDragging: Radius.zero,
+      controller: _controllerOne,
+      isAlwaysShown: true,
+      child: ListView.builder(
+        controller: _controllerOne,
+        itemCount: 120,
+        itemBuilder: (BuildContext context, int index) {
+          return Center(
+            child: Text('item $index'),
+          );
+        },
+      ),
+    );
+  }
+
+//* ▲▲▲▲▲▲▲▲ code ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//********************************************************************
+
+}

examples/api/lib/cupertino/text_form_field_row/cupertino_text_form_field_row.1.dart

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Template: dev/snippets/config/templates/stateful_widget_material.tmpl
+//
+// Comment lines marked with "▼▼▼" and "▲▲▲" are used for authoring
+// of samples, and may be ignored if you are just exploring the sample.
+
+// Flutter code sample for CupertinoTextFormFieldRow
+//
+//***************************************************************************
+//* ▼▼▼▼▼▼▼▼ description ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+// This example shows how to move the focus to the next field when the user
+// presses the SPACE key.
+
+//* ▲▲▲▲▲▲▲▲ description ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//***************************************************************************
+
+//****************************************************************************
+//* ▼▼▼▼▼▼▼▼ code-imports ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+import 'package:flutter/cupertino.dart';
+
+//* ▲▲▲▲▲▲▲▲ code-imports ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//****************************************************************************
+
+import 'package:flutter/material.dart';
+
+void main() => runApp(const MyApp());
+
+/// This is the main application widget.
+class MyApp extends StatelessWidget {
+  const MyApp({Key? key}) : super(key: key);
+
+  static const String _title = 'Flutter Code Sample';
+
+  @override
+  Widget build(BuildContext context) {
+    return const MaterialApp(
+      title: _title,
+      home: MyStatefulWidget(),
+    );
+  }
+}
+
+/// This is the stateful widget that the main application instantiates.
+class MyStatefulWidget extends StatefulWidget {
+  const MyStatefulWidget({Key? key}) : super(key: key);
+
+  @override
+  State<MyStatefulWidget> createState() => _MyStatefulWidgetState();
+}
+
+/// This is the private State class that goes with MyStatefulWidget.
+class _MyStatefulWidgetState extends State<MyStatefulWidget> {
+//********************************************************************
+//* ▼▼▼▼▼▼▼▼ code ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+  @override
+  Widget build(BuildContext context) {
+    return CupertinoPageScaffold(
+      child: Center(
+        child: Form(
+          autovalidateMode: AutovalidateMode.always,
+          onChanged: () {
+            Form.of(primaryFocus!.context!)?.save();
+          },
+          child: CupertinoFormSection.insetGrouped(
+            header: const Text('SECTION 1'),
+            children: List<Widget>.generate(5, (int index) {
+              return CupertinoTextFormFieldRow(
+                prefix: const Text('Enter text'),
+                placeholder: 'Enter text',
+                validator: (String? value) {
+                  if (value == null || value.isEmpty) {
+                    return 'Please enter a value';
+                  }
+                  return null;
+                },
+              );
+            }),
+          ),
+        ),
+      ),
+    );
+  }
+
+//* ▲▲▲▲▲▲▲▲ code ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//********************************************************************
+
+}

examples/api/lib/gestures/pointer_signal_resolver/pointer_signal_resolver.0.dart

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Template: dev/snippets/config/templates/stateful_widget_material.tmpl
+//
+// Comment lines marked with "▼▼▼" and "▲▲▲" are used for authoring
+// of samples, and may be ignored if you are just exploring the sample.
+
+// Flutter code sample for PointerSignalResolver
+//
+//***************************************************************************
+//* ▼▼▼▼▼▼▼▼ description ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+// Here is an example that demonstrates the effect of not using the resolver
+// versus using it.
+//
+// When this example is set to _not_ use the resolver, then triggering the
+// mouse wheel over the outer box will cause only the outer box to change
+// color, but triggering the mouse wheel over the inner box will cause _both_
+// the outer and the inner boxes to change color (because they're both
+// receiving the event).
+//
+// When this example is set to _use_ the resolver, then only the box located
+// directly under the cursor will change color when the mouse wheel is
+// triggered.
+
+//* ▲▲▲▲▲▲▲▲ description ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//***************************************************************************
+
+//****************************************************************************
+//* ▼▼▼▼▼▼▼▼ code-imports ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+import 'package:flutter/gestures.dart';
+
+//* ▲▲▲▲▲▲▲▲ code-imports ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//****************************************************************************
+
+import 'package:flutter/material.dart';
+
+void main() => runApp(const MyApp());
+
+/// This is the main application widget.
+class MyApp extends StatelessWidget {
+  const MyApp({Key? key}) : super(key: key);
+
+  static const String _title = 'Flutter Code Sample';
+
+  @override
+  Widget build(BuildContext context) {
+    return const MaterialApp(
+      title: _title,
+      home: MyStatefulWidget(),
+    );
+  }
+}
+
+//*****************************************************************************
+//* ▼▼▼▼▼▼▼▼ code-preamble ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+class ColorChanger extends StatefulWidget {
+  const ColorChanger({
+    Key? key,
+    required this.initialColor,
+    required this.useResolver,
+    this.child,
+  }) : super(key: key);
+
+  final HSVColor initialColor;
+  final bool useResolver;
+  final Widget? child;
+
+  @override
+  State<ColorChanger> createState() => _ColorChangerState();
+}
+
+class _ColorChangerState extends State<ColorChanger> {
+  late HSVColor color;
+
+  void rotateColor() {
+    setState(() {
+      color = color.withHue((color.hue + 3) % 360.0);
+    });
+  }
+
+  @override
+  void initState() {
+    super.initState();
+    color = widget.initialColor;
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return DecoratedBox(
+      decoration: BoxDecoration(
+        border: const Border.fromBorderSide(BorderSide()),
+        color: color.toColor(),
+      ),
+      child: Listener(
+        onPointerSignal: (PointerSignalEvent event) {
+          if (widget.useResolver) {
+            GestureBinding.instance!.pointerSignalResolver.register(event,
+                (PointerSignalEvent event) {
+              rotateColor();
+            });
+          } else {
+            rotateColor();
+          }
+        },
+        child: Stack(
+          fit: StackFit.expand,
+          children: <Widget>[
+            const AbsorbPointer(),
+            if (widget.child != null) widget.child!,
+          ],
+        ),
+      ),
+    );
+  }
+}
+
+//* ▲▲▲▲▲▲▲▲ code-preamble ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//*****************************************************************************
+
+/// This is the stateful widget that the main application instantiates.
+class MyStatefulWidget extends StatefulWidget {
+  const MyStatefulWidget({Key? key}) : super(key: key);
+
+  @override
+  State<MyStatefulWidget> createState() => _MyStatefulWidgetState();
+}
+
+/// This is the private State class that goes with MyStatefulWidget.
+class _MyStatefulWidgetState extends State<MyStatefulWidget> {
+//********************************************************************
+//* ▼▼▼▼▼▼▼▼ code ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+  bool useResolver = false;
+
+  @override
+  Widget build(BuildContext context) {
+    return Material(
+      child: Stack(
+        fit: StackFit.expand,
+        children: <Widget>[
+          ColorChanger(
+            initialColor: const HSVColor.fromAHSV(0.2, 120.0, 1, 1),
+            useResolver: useResolver,
+            child: FractionallySizedBox(
+              widthFactor: 0.5,
+              heightFactor: 0.5,
+              child: ColorChanger(
+                initialColor: const HSVColor.fromAHSV(1, 60.0, 1, 1),
+                useResolver: useResolver,
+              ),
+            ),
+          ),
+          Align(
+            alignment: Alignment.topLeft,
+            child: Row(
+              crossAxisAlignment: CrossAxisAlignment.center,
+              children: <Widget>[
+                Switch(
+                  value: useResolver,
+                  onChanged: (bool value) {
+                    setState(() {
+                      useResolver = value;
+                    });
+                  },
+                ),
+                const Text(
+                  'Use the PointerSignalResolver?',
+                  style: TextStyle(fontWeight: FontWeight.bold),
+                ),
+              ],
+            ),
+          ),
+        ],
+      ),
+    );
+  }
+
+//* ▲▲▲▲▲▲▲▲ code ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//********************************************************************
+
+}

examples/api/lib/material/about/about_list_tile.0.dart

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Template: dev/snippets/config/templates/stateless_widget_material.tmpl
+//
+// Comment lines marked with "▼▼▼" and "▲▲▲" are used for authoring
+// of samples, and may be ignored if you are just exploring the sample.
+
+// Flutter code sample for AboutListTile
+//
+//***************************************************************************
+//* ▼▼▼▼▼▼▼▼ description ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+// This sample shows two ways to open [AboutDialog]. The first one
+// uses an [AboutListTile], and the second uses the [showAboutDialog] function.
+
+//* ▲▲▲▲▲▲▲▲ description ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//***************************************************************************
+
+import 'package:flutter/material.dart';
+
+void main() => runApp(const MyApp());
+
+/// This is the main application widget.
+class MyApp extends StatelessWidget {
+  const MyApp({Key? key}) : super(key: key);
+
+  static const String _title = 'Flutter Code Sample';
+
+  @override
+  Widget build(BuildContext context) {
+    return const MaterialApp(
+      title: _title,
+      home: MyStatelessWidget(),
+    );
+  }
+}
+
+/// This is the stateless widget that the main application instantiates.
+class MyStatelessWidget extends StatelessWidget {
+  const MyStatelessWidget({Key? key}) : super(key: key);
+
+  @override
+//********************************************************************
+//* ▼▼▼▼▼▼▼▼ code ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+  Widget build(BuildContext context) {
+    final ThemeData theme = Theme.of(context);
+    final TextStyle textStyle = theme.textTheme.bodyText2!;
+    final List<Widget> aboutBoxChildren = <Widget>[
+      const SizedBox(height: 24),
+      RichText(
+        text: TextSpan(
+          children: <TextSpan>[
+            TextSpan(
+                style: textStyle,
+                text: "Flutter is Google's UI toolkit for building beautiful, "
+                    'natively compiled applications for mobile, web, and desktop '
+                    'from a single codebase. Learn more about Flutter at '),
+            TextSpan(
+                style: textStyle.copyWith(color: theme.colorScheme.primary),
+                text: 'https://flutter.dev'),
+            TextSpan(style: textStyle, text: '.'),
+          ],
+        ),
+      ),
+    ];
+
+    return Scaffold(
+      appBar: AppBar(
+        title: const Text('Show About Example'),
+      ),
+      drawer: Drawer(
+        child: SingleChildScrollView(
+          child: SafeArea(
+            child: AboutListTile(
+              icon: const Icon(Icons.info),
+              applicationIcon: const FlutterLogo(),
+              applicationName: 'Show About Example',
+              applicationVersion: 'August 2019',
+              applicationLegalese: '\u{a9} 2014 The Flutter Authors',
+              aboutBoxChildren: aboutBoxChildren,
+            ),
+          ),
+        ),
+      ),
+      body: Center(
+        child: ElevatedButton(
+          child: const Text('Show About Example'),
+          onPressed: () {
+            showAboutDialog(
+              context: context,
+              applicationIcon: const FlutterLogo(),
+              applicationName: 'Show About Example',
+              applicationVersion: 'August 2019',
+              applicationLegalese: '\u{a9} 2014 The Flutter Authors',
+              children: aboutBoxChildren,
+            );
+          },
+        ),
+      ),
+    );
+  }
+
+//* ▲▲▲▲▲▲▲▲ code ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//********************************************************************
+
+}

examples/api/lib/material/app_bar/app_bar.0.dart

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Template: dev/snippets/config/templates/stateless_widget_material.tmpl
+//
+// Comment lines marked with "▼▼▼" and "▲▲▲" are used for authoring
+// of samples, and may be ignored if you are just exploring the sample.
+
+// Flutter code sample for AppBar
+//
+//***************************************************************************
+//* ▼▼▼▼▼▼▼▼ description ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+// This sample shows an [AppBar] with two simple actions. The first action
+// opens a [SnackBar], while the second action navigates to a new page.
+
+//* ▲▲▲▲▲▲▲▲ description ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//***************************************************************************
+
+import 'package:flutter/material.dart';
+
+void main() => runApp(const MyApp());
+
+/// This is the main application widget.
+class MyApp extends StatelessWidget {
+  const MyApp({Key? key}) : super(key: key);
+
+  static const String _title = 'Flutter Code Sample';
+
+  @override
+  Widget build(BuildContext context) {
+    return const MaterialApp(
+      title: _title,
+      home: MyStatelessWidget(),
+    );
+  }
+}
+
+/// This is the stateless widget that the main application instantiates.
+class MyStatelessWidget extends StatelessWidget {
+  const MyStatelessWidget({Key? key}) : super(key: key);
+
+  @override
+//********************************************************************
+//* ▼▼▼▼▼▼▼▼ code ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+  Widget build(BuildContext context) {
+    return Scaffold(
+      appBar: AppBar(
+        title: const Text('AppBar Demo'),
+        actions: <Widget>[
+          IconButton(
+            icon: const Icon(Icons.add_alert),
+            tooltip: 'Show Snackbar',
+            onPressed: () {
+              ScaffoldMessenger.of(context).showSnackBar(
+                  const SnackBar(content: Text('This is a snackbar')));
+            },
+          ),
+          IconButton(
+            icon: const Icon(Icons.navigate_next),
+            tooltip: 'Go to the next page',
+            onPressed: () {
+              Navigator.push(context, MaterialPageRoute<void>(
+                builder: (BuildContext context) {
+                  return Scaffold(
+                    appBar: AppBar(
+                      title: const Text('Next page'),
+                    ),
+                    body: const Center(
+                      child: Text(
+                        'This is the next page',
+                        style: TextStyle(fontSize: 24),
+                      ),
+                    ),
+                  );
+                },
+              ));
+            },
+          ),
+        ],
+      ),
+      body: const Center(
+        child: Text(
+          'This is the home page',
+          style: TextStyle(fontSize: 24),
+        ),
+      ),
+    );
+  }
+
+//* ▲▲▲▲▲▲▲▲ code ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//********************************************************************
+
+}

examples/api/lib/material/app_bar/app_bar.1.dart

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Template: dev/snippets/config/templates/stateless_widget_material.tmpl
+//
+// Comment lines marked with "▼▼▼" and "▲▲▲" are used for authoring
+// of samples, and may be ignored if you are just exploring the sample.
+
+// Flutter code sample for AppBar
+//
+//***************************************************************************
+//* ▼▼▼▼▼▼▼▼ description ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+//
+
+//* ▲▲▲▲▲▲▲▲ description ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//***************************************************************************
+
+import 'package:flutter/material.dart';
+
+void main() => runApp(const MyApp());
+
+/// This is the main application widget.
+class MyApp extends StatelessWidget {
+  const MyApp({Key? key}) : super(key: key);
+
+  static const String _title = 'Flutter Code Sample';
+
+  @override
+  Widget build(BuildContext context) {
+    return const MaterialApp(
+      title: _title,
+      home: MyStatelessWidget(),
+    );
+  }
+}
+
+/// This is the stateless widget that the main application instantiates.
+class MyStatelessWidget extends StatelessWidget {
+  const MyStatelessWidget({Key? key}) : super(key: key);
+
+  @override
+//********************************************************************
+//* ▼▼▼▼▼▼▼▼ code ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+  Widget build(BuildContext context) {
+    final ButtonStyle style =
+        TextButton.styleFrom(primary: Theme.of(context).colorScheme.onPrimary);
+    return Scaffold(
+      appBar: AppBar(
+        actions: <Widget>[
+          TextButton(
+            style: style,
+            onPressed: () {},
+            child: const Text('Action 1'),
+          ),
+          TextButton(
+            style: style,
+            onPressed: () {},
+            child: const Text('Action 2'),
+          )
+        ],
+      ),
+    );
+  }
+
+//* ▲▲▲▲▲▲▲▲ code ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//********************************************************************
+
+}

examples/api/lib/material/app_bar/sliver_app_bar.1.dart

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Template: dev/snippets/config/templates/stateful_widget_material.tmpl
+//
+// Comment lines marked with "▼▼▼" and "▲▲▲" are used for authoring
+// of samples, and may be ignored if you are just exploring the sample.
+
+// Flutter code sample for SliverAppBar
+//
+//***************************************************************************
+//* ▼▼▼▼▼▼▼▼ description ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+// This sample shows a [SliverAppBar] and it's behavior when using the
+// [pinned], [snap] and [floating] parameters.
+
+//* ▲▲▲▲▲▲▲▲ description ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//***************************************************************************
+
+import 'package:flutter/material.dart';
+
+void main() => runApp(const MyApp());
+
+/// This is the main application widget.
+class MyApp extends StatelessWidget {
+  const MyApp({Key? key}) : super(key: key);
+
+  static const String _title = 'Flutter Code Sample';
+
+  @override
+  Widget build(BuildContext context) {
+    return const MaterialApp(
+      title: _title,
+      home: MyStatefulWidget(),
+    );
+  }
+}
+
+/// This is the stateful widget that the main application instantiates.
+class MyStatefulWidget extends StatefulWidget {
+  const MyStatefulWidget({Key? key}) : super(key: key);
+
+  @override
+  State<MyStatefulWidget> createState() => _MyStatefulWidgetState();
+}
+
+/// This is the private State class that goes with MyStatefulWidget.
+class _MyStatefulWidgetState extends State<MyStatefulWidget> {
+//********************************************************************
+//* ▼▼▼▼▼▼▼▼ code ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+  bool _pinned = true;
+  bool _snap = false;
+  bool _floating = false;
+
+// [SliverAppBar]s are typically used in [CustomScrollView.slivers], which in
+// turn can be placed in a [Scaffold.body].
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      body: CustomScrollView(
+        slivers: <Widget>[
+          SliverAppBar(
+            pinned: _pinned,
+            snap: _snap,
+            floating: _floating,
+            expandedHeight: 160.0,
+            flexibleSpace: const FlexibleSpaceBar(
+              title: Text('SliverAppBar'),
+              background: FlutterLogo(),
+            ),
+          ),
+          const SliverToBoxAdapter(
+            child: SizedBox(
+              height: 20,
+              child: Center(
+                child: Text('Scroll to see the SliverAppBar in effect.'),
+              ),
+            ),
+          ),
+          SliverList(
+            delegate: SliverChildBuilderDelegate(
+              (BuildContext context, int index) {
+                return Container(
+                  color: index.isOdd ? Colors.white : Colors.black12,
+                  height: 100.0,
+                  child: Center(
+                    child: Text('$index', textScaleFactor: 5),
+                  ),
+                );
+              },
+              childCount: 20,
+            ),
+          ),
+        ],
+      ),
+      bottomNavigationBar: BottomAppBar(
+        child: Padding(
+          padding: const EdgeInsets.all(8),
+          child: OverflowBar(
+            overflowAlignment: OverflowBarAlignment.center,
+            children: <Widget>[
+              Row(
+                mainAxisSize: MainAxisSize.min,
+                children: <Widget>[
+                  const Text('pinned'),
+                  Switch(
+                    onChanged: (bool val) {
+                      setState(() {
+                        _pinned = val;
+                      });
+                    },
+                    value: _pinned,
+                  ),
+                ],
+              ),
+              Row(
+                mainAxisSize: MainAxisSize.min,
+                children: <Widget>[
+                  const Text('snap'),
+                  Switch(
+                    onChanged: (bool val) {
+                      setState(() {
+                        _snap = val;
+                        // Snapping only applies when the app bar is floating.
+                        _floating = _floating || _snap;
+                      });
+                    },
+                    value: _snap,
+                  ),
+                ],
+              ),
+              Row(
+                mainAxisSize: MainAxisSize.min,
+                children: <Widget>[
+                  const Text('floating'),
+                  Switch(
+                    onChanged: (bool val) {
+                      setState(() {
+                        _floating = val;
+                        _snap = _snap && _floating;
+                      });
+                    },
+                    value: _floating,
+                  ),
+                ],
+              ),
+            ],
+          ),
+        ),
+      ),
+    );
+  }
+
+//* ▲▲▲▲▲▲▲▲ code ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//********************************************************************
+
+}

examples/api/lib/material/autocomplete/autocomplete.0.dart

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Template: dev/snippets/config/templates/freeform.tmpl
+//
+// Comment lines marked with "▼▼▼" and "▲▲▲" are used for authoring
+// of samples, and may be ignored if you are just exploring the sample.
+
+// Flutter code sample for Autocomplete
+//
+//***************************************************************************
+//* ▼▼▼▼▼▼▼▼ description ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+// This example shows how to create a very basic Autocomplete widget using the
+// default UI.
+
+//* ▲▲▲▲▲▲▲▲ description ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//***************************************************************************
+
+//*************************************************************************
+//* ▼▼▼▼▼▼▼▼ code-main ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+import 'package:flutter/material.dart';
+
+void main() => runApp(const AutocompleteExampleApp());
+
+class AutocompleteExampleApp extends StatelessWidget {
+  const AutocompleteExampleApp({Key? key}) : super(key: key);
+
+  @override
+  Widget build(BuildContext context) {
+    return MaterialApp(
+      home: Scaffold(
+        appBar: AppBar(
+          title: const Text('Autocomplete Basic'),
+        ),
+        body: const Center(
+          child: AutocompleteBasicExample(),
+        ),
+      ),
+    );
+  }
+}
+
+class AutocompleteBasicExample extends StatelessWidget {
+  const AutocompleteBasicExample({Key? key}) : super(key: key);
+
+  static const List<String> _kOptions = <String>[
+    'aardvark',
+    'bobcat',
+    'chameleon',
+  ];
+
+  @override
+  Widget build(BuildContext context) {
+    return Autocomplete<String>(
+      optionsBuilder: (TextEditingValue textEditingValue) {
+        if (textEditingValue.text == '') {
+          return const Iterable<String>.empty();
+        }
+        return _kOptions.where((String option) {
+          return option.contains(textEditingValue.text.toLowerCase());
+        });
+      },
+      onSelected: (String selection) {
+        print('You just selected $selection');
+      },
+    );
+  }
+}
+
+//* ▲▲▲▲▲▲▲▲ code-main ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//*************************************************************************

examples/api/lib/material/autocomplete/autocomplete.1.dart

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Template: dev/snippets/config/templates/freeform.tmpl
+//
+// Comment lines marked with "▼▼▼" and "▲▲▲" are used for authoring
+// of samples, and may be ignored if you are just exploring the sample.
+
+// Flutter code sample for Autocomplete
+//
+//***************************************************************************
+//* ▼▼▼▼▼▼▼▼ description ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+// This example shows how to create an Autocomplete widget with a custom type.
+// Try searching with text from the name or email field.
+
+//* ▲▲▲▲▲▲▲▲ description ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//***************************************************************************
+
+//*************************************************************************
+//* ▼▼▼▼▼▼▼▼ code-main ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+import 'package:flutter/material.dart';
+
+void main() => runApp(const AutocompleteExampleApp());
+
+class AutocompleteExampleApp extends StatelessWidget {
+  const AutocompleteExampleApp({Key? key}) : super(key: key);
+
+  @override
+  Widget build(BuildContext context) {
+    return MaterialApp(
+      home: Scaffold(
+        appBar: AppBar(
+          title: const Text('Autocomplete Basic User'),
+        ),
+        body: const Center(
+          child: AutocompleteBasicUserExample(),
+        ),
+      ),
+    );
+  }
+}
+
+@immutable
+class User {
+  const User({
+    required this.email,
+    required this.name,
+  });
+
+  final String email;
+  final String name;
+
+  @override
+  String toString() {
+    return '$name, $email';
+  }
+
+  @override
+  bool operator ==(Object other) {
+    if (other.runtimeType != runtimeType) {
+      return false;
+    }
+    return other is User && other.name == name && other.email == email;
+  }
+
+  @override
+  int get hashCode => hashValues(email, name);
+}
+
+class AutocompleteBasicUserExample extends StatelessWidget {
+  const AutocompleteBasicUserExample({Key? key}) : super(key: key);
+
+  static const List<User> _userOptions = <User>[
+    User(name: 'Alice', email: 'alice@example.com'),
+    User(name: 'Bob', email: 'bob@example.com'),
+    User(name: 'Charlie', email: 'charlie123@gmail.com'),
+  ];
+
+  static String _displayStringForOption(User option) => option.name;
+
+  @override
+  Widget build(BuildContext context) {
+    return Autocomplete<User>(
+      displayStringForOption: _displayStringForOption,
+      optionsBuilder: (TextEditingValue textEditingValue) {
+        if (textEditingValue.text == '') {
+          return const Iterable<User>.empty();
+        }
+        return _userOptions.where((User option) {
+          return option
+              .toString()
+              .contains(textEditingValue.text.toLowerCase());
+        });
+      },
+      onSelected: (User selection) {
+        print('You just selected ${_displayStringForOption(selection)}');
+      },
+    );
+  }
+}
+
+//* ▲▲▲▲▲▲▲▲ code-main ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//*************************************************************************

examples/api/lib/material/banner/material_banner.0.dart

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Template: dev/snippets/config/templates/stateless_widget_material.tmpl
+//
+// Comment lines marked with "▼▼▼" and "▲▲▲" are used for authoring
+// of samples, and may be ignored if you are just exploring the sample.
+
+// Flutter code sample for MaterialBanner
+//
+//***************************************************************************
+//* ▼▼▼▼▼▼▼▼ description ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+// Banners placed directly into the widget tree are static.
+
+//* ▲▲▲▲▲▲▲▲ description ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//***************************************************************************
+
+import 'package:flutter/material.dart';
+
+void main() => runApp(const MyApp());
+
+/// This is the main application widget.
+class MyApp extends StatelessWidget {
+  const MyApp({Key? key}) : super(key: key);
+
+  static const String _title = 'Flutter Code Sample';
+
+  @override
+  Widget build(BuildContext context) {
+    return const MaterialApp(
+      title: _title,
+      home: MyStatelessWidget(),
+    );
+  }
+}
+
+/// This is the stateless widget that the main application instantiates.
+class MyStatelessWidget extends StatelessWidget {
+  const MyStatelessWidget({Key? key}) : super(key: key);
+
+  @override
+//********************************************************************
+//* ▼▼▼▼▼▼▼▼ code ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+  Widget build(BuildContext context) {
+    return Scaffold(
+      appBar: AppBar(
+        title: const Text('The MaterialBanner is below'),
+      ),
+      body: const MaterialBanner(
+        padding: EdgeInsets.all(20),
+        content: Text('Hello, I am a Material Banner'),
+        leading: Icon(Icons.agriculture_outlined),
+        backgroundColor: Color(0xFFE0E0E0),
+        actions: <Widget>[
+          TextButton(
+            child: Text('OPEN'),
+            onPressed: null,
+          ),
+          TextButton(
+            child: Text('DISMISS'),
+            onPressed: null,
+          ),
+        ],
+      ),
+    );
+  }
+
+//* ▲▲▲▲▲▲▲▲ code ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//********************************************************************
+
+}

examples/api/lib/material/banner/material_banner.1.dart

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Template: dev/snippets/config/templates/stateless_widget_material.tmpl
+//
+// Comment lines marked with "▼▼▼" and "▲▲▲" are used for authoring
+// of samples, and may be ignored if you are just exploring the sample.
+
+// Flutter code sample for MaterialBanner
+//
+//***************************************************************************
+//* ▼▼▼▼▼▼▼▼ description ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+// MaterialBanner's can also be presented through a [ScaffoldMessenger].
+// Here is an example where ScaffoldMessengerState.showMaterialBanner() is used to show the MaterialBanner.
+
+//* ▲▲▲▲▲▲▲▲ description ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//***************************************************************************
+
+import 'package:flutter/material.dart';
+
+void main() => runApp(const MyApp());
+
+/// This is the main application widget.
+class MyApp extends StatelessWidget {
+  const MyApp({Key? key}) : super(key: key);
+
+  static const String _title = 'Flutter Code Sample';
+
+  @override
+  Widget build(BuildContext context) {
+    return const MaterialApp(
+      title: _title,
+      home: MyStatelessWidget(),
+    );
+  }
+}
+
+/// This is the stateless widget that the main application instantiates.
+class MyStatelessWidget extends StatelessWidget {
+  const MyStatelessWidget({Key? key}) : super(key: key);
+
+  @override
+//********************************************************************
+//* ▼▼▼▼▼▼▼▼ code ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+  Widget build(BuildContext context) {
+    return Scaffold(
+      appBar: AppBar(
+        title: const Text('The MaterialBanner is below'),
+      ),
+      body: Center(
+        child: ElevatedButton(
+          child: const Text('Show MaterialBanner'),
+          onPressed: () => ScaffoldMessenger.of(context).showMaterialBanner(
+            const MaterialBanner(
+              padding: EdgeInsets.all(20),
+              content: Text('Hello, I am a Material Banner'),
+              leading: Icon(Icons.agriculture_outlined),
+              backgroundColor: Colors.green,
+              actions: <Widget>[
+                TextButton(
+                  child: Text('DISMISS'),
+                  onPressed: null,
+                ),
+              ],
+            ),
+          ),
+        ),
+      ),
+    );
+  }
+
+//* ▲▲▲▲▲▲▲▲ code ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//********************************************************************
+
+}

examples/api/lib/material/bottom_app_bar/bottom_app_bar.1.dart

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Template: dev/snippets/config/templates/freeform.tmpl
+//
+// Comment lines marked with "▼▼▼" and "▲▲▲" are used for authoring
+// of samples, and may be ignored if you are just exploring the sample.
+
+// Flutter code sample for BottomAppBar
+//
+//***************************************************************************
+//* ▼▼▼▼▼▼▼▼ description ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+// This example shows the [BottomAppBar], which can be configured to have a notch using the
+// [BottomAppBar.shape] property. This also includes an optional [FloatingActionButton], which illustrates
+// the [FloatingActionButtonLocation]s in relation to the [BottomAppBar].
+
+//* ▲▲▲▲▲▲▲▲ description ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//***************************************************************************
+
+//****************************************************************************
+//* ▼▼▼▼▼▼▼▼ code-imports ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+import 'package:flutter/material.dart';
+
+//* ▲▲▲▲▲▲▲▲ code-imports ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//****************************************************************************
+
+//********************************************************************
+//* ▼▼▼▼▼▼▼▼ code ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+void main() {
+  runApp(const BottomAppBarDemo());
+}
+
+class BottomAppBarDemo extends StatefulWidget {
+  const BottomAppBarDemo({Key? key}) : super(key: key);
+
+  @override
+  State createState() => _BottomAppBarDemoState();
+}
+
+class _BottomAppBarDemoState extends State<BottomAppBarDemo> {
+  bool _showFab = true;
+  bool _showNotch = true;
+  FloatingActionButtonLocation _fabLocation =
+      FloatingActionButtonLocation.endDocked;
+
+  void _onShowNotchChanged(bool value) {
+    setState(() {
+      _showNotch = value;
+    });
+  }
+
+  void _onShowFabChanged(bool value) {
+    setState(() {
+      _showFab = value;
+    });
+  }
+
+  void _onFabLocationChanged(FloatingActionButtonLocation? value) {
+    setState(() {
+      _fabLocation = value ?? FloatingActionButtonLocation.endDocked;
+    });
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return MaterialApp(
+      home: Scaffold(
+        appBar: AppBar(
+          automaticallyImplyLeading: false,
+          title: const Text('Bottom App Bar Demo'),
+        ),
+        body: ListView(
+          padding: const EdgeInsets.only(bottom: 88),
+          children: <Widget>[
+            SwitchListTile(
+              title: const Text(
+                'Floating Action Button',
+              ),
+              value: _showFab,
+              onChanged: _onShowFabChanged,
+            ),
+            SwitchListTile(
+              title: const Text('Notch'),
+              value: _showNotch,
+              onChanged: _onShowNotchChanged,
+            ),
+            const Padding(
+              padding: EdgeInsets.all(16),
+              child: Text('Floating action button position'),
+            ),
+            RadioListTile<FloatingActionButtonLocation>(
+              title: const Text('Docked - End'),
+              value: FloatingActionButtonLocation.endDocked,
+              groupValue: _fabLocation,
+              onChanged: _onFabLocationChanged,
+            ),
+            RadioListTile<FloatingActionButtonLocation>(
+              title: const Text('Docked - Center'),
+              value: FloatingActionButtonLocation.centerDocked,
+              groupValue: _fabLocation,
+              onChanged: _onFabLocationChanged,
+            ),
+            RadioListTile<FloatingActionButtonLocation>(
+              title: const Text('Floating - End'),
+              value: FloatingActionButtonLocation.endFloat,
+              groupValue: _fabLocation,
+              onChanged: _onFabLocationChanged,
+            ),
+            RadioListTile<FloatingActionButtonLocation>(
+              title: const Text('Floating - Center'),
+              value: FloatingActionButtonLocation.centerFloat,
+              groupValue: _fabLocation,
+              onChanged: _onFabLocationChanged,
+            ),
+          ],
+        ),
+        floatingActionButton: _showFab
+            ? FloatingActionButton(
+                onPressed: () {},
+                child: const Icon(Icons.add),
+                tooltip: 'Create',
+              )
+            : null,
+        floatingActionButtonLocation: _fabLocation,
+        bottomNavigationBar: _DemoBottomAppBar(
+          fabLocation: _fabLocation,
+          shape: _showNotch ? const CircularNotchedRectangle() : null,
+        ),
+      ),
+    );
+  }
+}
+
+class _DemoBottomAppBar extends StatelessWidget {
+  const _DemoBottomAppBar({
+    this.fabLocation = FloatingActionButtonLocation.endDocked,
+    this.shape = const CircularNotchedRectangle(),
+  });
+
+  final FloatingActionButtonLocation fabLocation;
+  final NotchedShape? shape;
+
+  static final List<FloatingActionButtonLocation> centerLocations =
+      <FloatingActionButtonLocation>[
+    FloatingActionButtonLocation.centerDocked,
+    FloatingActionButtonLocation.centerFloat,
+  ];
+
+  @override
+  Widget build(BuildContext context) {
+    return BottomAppBar(
+      shape: shape,
+      color: Colors.blue,
+      child: IconTheme(
+        data: IconThemeData(color: Theme.of(context).colorScheme.onPrimary),
+        child: Row(
+          children: <Widget>[
+            IconButton(
+              tooltip: 'Open navigation menu',
+              icon: const Icon(Icons.menu),
+              onPressed: () {},
+            ),
+            if (centerLocations.contains(fabLocation)) const Spacer(),
+            IconButton(
+              tooltip: 'Search',
+              icon: const Icon(Icons.search),
+              onPressed: () {},
+            ),
+            IconButton(
+              tooltip: 'Favorite',
+              icon: const Icon(Icons.favorite),
+              onPressed: () {},
+            ),
+          ],
+        ),
+      ),
+    );
+  }
+}
+
+//* ▲▲▲▲▲▲▲▲ code ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//********************************************************************

examples/api/lib/material/bottom_navigation_bar/bottom_navigation_bar.0.dart

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Template: dev/snippets/config/templates/stateful_widget_material.tmpl
+//
+// Comment lines marked with "▼▼▼" and "▲▲▲" are used for authoring
+// of samples, and may be ignored if you are just exploring the sample.
+
+// Flutter code sample for BottomNavigationBar
+//
+//***************************************************************************
+//* ▼▼▼▼▼▼▼▼ description ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+// This example shows a [BottomNavigationBar] as it is used within a [Scaffold]
+// widget. The [BottomNavigationBar] has three [BottomNavigationBarItem]
+// widgets, which means it defaults to [BottomNavigationBarType.fixed], and
+// the [currentIndex] is set to index 0. The selected item is
+// amber. The `_onItemTapped` function changes the selected item's index
+// and displays a corresponding message in the center of the [Scaffold].
+
+//* ▲▲▲▲▲▲▲▲ description ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//***************************************************************************
+
+import 'package:flutter/material.dart';
+
+void main() => runApp(const MyApp());
+
+/// This is the main application widget.
+class MyApp extends StatelessWidget {
+  const MyApp({Key? key}) : super(key: key);
+
+  static const String _title = 'Flutter Code Sample';
+
+  @override
+  Widget build(BuildContext context) {
+    return const MaterialApp(
+      title: _title,
+      home: MyStatefulWidget(),
+    );
+  }
+}
+
+/// This is the stateful widget that the main application instantiates.
+class MyStatefulWidget extends StatefulWidget {
+  const MyStatefulWidget({Key? key}) : super(key: key);
+
+  @override
+  State<MyStatefulWidget> createState() => _MyStatefulWidgetState();
+}
+
+/// This is the private State class that goes with MyStatefulWidget.
+class _MyStatefulWidgetState extends State<MyStatefulWidget> {
+//********************************************************************
+//* ▼▼▼▼▼▼▼▼ code ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+  int _selectedIndex = 0;
+  static const TextStyle optionStyle =
+      TextStyle(fontSize: 30, fontWeight: FontWeight.bold);
+  static const List<Widget> _widgetOptions = <Widget>[
+    Text(
+      'Index 0: Home',
+      style: optionStyle,
+    ),
+    Text(
+      'Index 1: Business',
+      style: optionStyle,
+    ),
+    Text(
+      'Index 2: School',
+      style: optionStyle,
+    ),
+  ];
+
+  void _onItemTapped(int index) {
+    setState(() {
+      _selectedIndex = index;
+    });
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      appBar: AppBar(
+        title: const Text('BottomNavigationBar Sample'),
+      ),
+      body: Center(
+        child: _widgetOptions.elementAt(_selectedIndex),
+      ),
+      bottomNavigationBar: BottomNavigationBar(
+        items: const <BottomNavigationBarItem>[
+          BottomNavigationBarItem(
+            icon: Icon(Icons.home),
+            label: 'Home',
+          ),
+          BottomNavigationBarItem(
+            icon: Icon(Icons.business),
+            label: 'Business',
+          ),
+          BottomNavigationBarItem(
+            icon: Icon(Icons.school),
+            label: 'School',
+          ),
+        ],
+        currentIndex: _selectedIndex,
+        selectedItemColor: Colors.amber[800],
+        onTap: _onItemTapped,
+      ),
+    );
+  }
+
+//* ▲▲▲▲▲▲▲▲ code ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//********************************************************************
+
+}

examples/api/lib/material/bottom_navigation_bar/bottom_navigation_bar.1.dart

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Template: dev/snippets/config/templates/stateful_widget_material.tmpl
+//
+// Comment lines marked with "▼▼▼" and "▲▲▲" are used for authoring
+// of samples, and may be ignored if you are just exploring the sample.
+
+// Flutter code sample for BottomNavigationBar
+//
+//***************************************************************************
+//* ▼▼▼▼▼▼▼▼ description ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+// This example shows a [BottomNavigationBar] as it is used within a [Scaffold]
+// widget. The [BottomNavigationBar] has four [BottomNavigationBarItem]
+// widgets, which means it defaults to [BottomNavigationBarType.shifting], and
+// the [currentIndex] is set to index 0. The selected item is amber in color.
+// With each [BottomNavigationBarItem] widget, backgroundColor property is
+// also defined, which changes the background color of [BottomNavigationBar],
+// when that item is selected. The `_onItemTapped` function changes the
+// selected item's index and displays a corresponding message in the center of
+// the [Scaffold].
+
+//* ▲▲▲▲▲▲▲▲ description ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//***************************************************************************
+
+import 'package:flutter/material.dart';
+
+void main() => runApp(const MyApp());
+
+/// This is the main application widget.
+class MyApp extends StatelessWidget {
+  const MyApp({Key? key}) : super(key: key);
+
+  static const String _title = 'Flutter Code Sample';
+
+  @override
+  Widget build(BuildContext context) {
+    return const MaterialApp(
+      title: _title,
+      home: MyStatefulWidget(),
+    );
+  }
+}
+
+/// This is the stateful widget that the main application instantiates.
+class MyStatefulWidget extends StatefulWidget {
+  const MyStatefulWidget({Key? key}) : super(key: key);
+
+  @override
+  State<MyStatefulWidget> createState() => _MyStatefulWidgetState();
+}
+
+/// This is the private State class that goes with MyStatefulWidget.
+class _MyStatefulWidgetState extends State<MyStatefulWidget> {
+//********************************************************************
+//* ▼▼▼▼▼▼▼▼ code ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+  int _selectedIndex = 0;
+  static const TextStyle optionStyle =
+      TextStyle(fontSize: 30, fontWeight: FontWeight.bold);
+  static const List<Widget> _widgetOptions = <Widget>[
+    Text(
+      'Index 0: Home',
+      style: optionStyle,
+    ),
+    Text(
+      'Index 1: Business',
+      style: optionStyle,
+    ),
+    Text(
+      'Index 2: School',
+      style: optionStyle,
+    ),
+    Text(
+      'Index 3: Settings',
+      style: optionStyle,
+    ),
+  ];
+
+  void _onItemTapped(int index) {
+    setState(() {
+      _selectedIndex = index;
+    });
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      appBar: AppBar(
+        title: const Text('BottomNavigationBar Sample'),
+      ),
+      body: Center(
+        child: _widgetOptions.elementAt(_selectedIndex),
+      ),
+      bottomNavigationBar: BottomNavigationBar(
+        items: const <BottomNavigationBarItem>[
+          BottomNavigationBarItem(
+            icon: Icon(Icons.home),
+            label: 'Home',
+            backgroundColor: Colors.red,
+          ),
+          BottomNavigationBarItem(
+            icon: Icon(Icons.business),
+            label: 'Business',
+            backgroundColor: Colors.green,
+          ),
+          BottomNavigationBarItem(
+            icon: Icon(Icons.school),
+            label: 'School',
+            backgroundColor: Colors.purple,
+          ),
+          BottomNavigationBarItem(
+            icon: Icon(Icons.settings),
+            label: 'Settings',
+            backgroundColor: Colors.pink,
+          ),
+        ],
+        currentIndex: _selectedIndex,
+        selectedItemColor: Colors.amber[800],
+        onTap: _onItemTapped,
+      ),
+    );
+  }
+
+//* ▲▲▲▲▲▲▲▲ code ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//********************************************************************
+
+}

examples/api/lib/material/bottom_sheet/show_modal_bottom_sheet.0.dart

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Template: dev/snippets/config/templates/stateless_widget_scaffold.tmpl
+//
+// Comment lines marked with "▼▼▼" and "▲▲▲" are used for authoring
+// of samples, and may be ignored if you are just exploring the sample.
+
+// Flutter code sample for showModalBottomSheet
+//
+//***************************************************************************
+//* ▼▼▼▼▼▼▼▼ description ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+// This example demonstrates how to use `showModalBottomSheet` to display a
+// bottom sheet that obscures the content behind it when a user taps a button.
+// It also demonstrates how to close the bottom sheet using the [Navigator]
+// when a user taps on a button inside the bottom sheet.
+
+//* ▲▲▲▲▲▲▲▲ description ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//***************************************************************************
+
+import 'package:flutter/material.dart';
+
+void main() => runApp(const MyApp());
+
+/// This is the main application widget.
+class MyApp extends StatelessWidget {
+  const MyApp({Key? key}) : super(key: key);
+
+  static const String _title = 'Flutter Code Sample';
+
+  @override
+  Widget build(BuildContext context) {
+    return MaterialApp(
+      title: _title,
+      home: Scaffold(
+        appBar: AppBar(title: const Text(_title)),
+        body: const MyStatelessWidget(),
+      ),
+    );
+  }
+}
+
+/// This is the stateless widget that the main application instantiates.
+class MyStatelessWidget extends StatelessWidget {
+  const MyStatelessWidget({Key? key}) : super(key: key);
+
+  @override
+//********************************************************************
+//* ▼▼▼▼▼▼▼▼ code ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+  Widget build(BuildContext context) {
+    return Center(
+      child: ElevatedButton(
+        child: const Text('showModalBottomSheet'),
+        onPressed: () {
+          showModalBottomSheet<void>(
+            context: context,
+            builder: (BuildContext context) {
+              return Container(
+                height: 200,
+                color: Colors.amber,
+                child: Center(
+                  child: Column(
+                    mainAxisAlignment: MainAxisAlignment.center,
+                    mainAxisSize: MainAxisSize.min,
+                    children: <Widget>[
+                      const Text('Modal BottomSheet'),
+                      ElevatedButton(
+                        child: const Text('Close BottomSheet'),
+                        onPressed: () => Navigator.pop(context),
+                      )
+                    ],
+                  ),
+                ),
+              );
+            },
+          );
+        },
+      ),
+    );
+  }
+
+//* ▲▲▲▲▲▲▲▲ code ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//********************************************************************
+
+}

examples/api/lib/material/card/card.0.dart

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Template: dev/snippets/config/templates/stateless_widget_scaffold.tmpl
+//
+// Comment lines marked with "▼▼▼" and "▲▲▲" are used for authoring
+// of samples, and may be ignored if you are just exploring the sample.
+
+// Flutter code sample for Card
+//
+//***************************************************************************
+//* ▼▼▼▼▼▼▼▼ description ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+// This sample shows creation of a [Card] widget that shows album information
+// and two actions.
+
+//* ▲▲▲▲▲▲▲▲ description ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//***************************************************************************
+
+import 'package:flutter/material.dart';
+
+void main() => runApp(const MyApp());
+
+/// This is the main application widget.
+class MyApp extends StatelessWidget {
+  const MyApp({Key? key}) : super(key: key);
+
+  static const String _title = 'Flutter Code Sample';
+
+  @override
+  Widget build(BuildContext context) {
+    return MaterialApp(
+      title: _title,
+      home: Scaffold(
+        appBar: AppBar(title: const Text(_title)),
+        body: const MyStatelessWidget(),
+      ),
+    );
+  }
+}
+
+/// This is the stateless widget that the main application instantiates.
+class MyStatelessWidget extends StatelessWidget {
+  const MyStatelessWidget({Key? key}) : super(key: key);
+
+  @override
+//********************************************************************
+//* ▼▼▼▼▼▼▼▼ code ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+  Widget build(BuildContext context) {
+    return Center(
+      child: Card(
+        child: Column(
+          mainAxisSize: MainAxisSize.min,
+          children: <Widget>[
+            const ListTile(
+              leading: Icon(Icons.album),
+              title: Text('The Enchanted Nightingale'),
+              subtitle: Text('Music by Julie Gable. Lyrics by Sidney Stein.'),
+            ),
+            Row(
+              mainAxisAlignment: MainAxisAlignment.end,
+              children: <Widget>[
+                TextButton(
+                  child: const Text('BUY TICKETS'),
+                  onPressed: () {/* ... */},
+                ),
+                const SizedBox(width: 8),
+                TextButton(
+                  child: const Text('LISTEN'),
+                  onPressed: () {/* ... */},
+                ),
+                const SizedBox(width: 8),
+              ],
+            ),
+          ],
+        ),
+      ),
+    );
+  }
+
+//* ▲▲▲▲▲▲▲▲ code ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//********************************************************************
+
+}

examples/api/lib/material/card/card.1.dart

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Template: dev/snippets/config/templates/stateless_widget_scaffold.tmpl
+//
+// Comment lines marked with "▼▼▼" and "▲▲▲" are used for authoring
+// of samples, and may be ignored if you are just exploring the sample.
+
+// Flutter code sample for Card
+//
+//***************************************************************************
+//* ▼▼▼▼▼▼▼▼ description ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+// This sample shows creation of a [Card] widget that can be tapped. When
+// tapped this [Card]'s [InkWell] displays an "ink splash" that fills the
+// entire card.
+
+//* ▲▲▲▲▲▲▲▲ description ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//***************************************************************************
+
+import 'package:flutter/material.dart';
+
+void main() => runApp(const MyApp());
+
+/// This is the main application widget.
+class MyApp extends StatelessWidget {
+  const MyApp({Key? key}) : super(key: key);
+
+  static const String _title = 'Flutter Code Sample';
+
+  @override
+  Widget build(BuildContext context) {
+    return MaterialApp(
+      title: _title,
+      home: Scaffold(
+        appBar: AppBar(title: const Text(_title)),
+        body: const MyStatelessWidget(),
+      ),
+    );
+  }
+}
+
+/// This is the stateless widget that the main application instantiates.
+class MyStatelessWidget extends StatelessWidget {
+  const MyStatelessWidget({Key? key}) : super(key: key);
+
+  @override
+//********************************************************************
+//* ▼▼▼▼▼▼▼▼ code ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+  Widget build(BuildContext context) {
+    return Center(
+      child: Card(
+        child: InkWell(
+          splashColor: Colors.blue.withAlpha(30),
+          onTap: () {
+            print('Card tapped.');
+          },
+          child: const SizedBox(
+            width: 300,
+            height: 100,
+            child: Text('A card that can be tapped'),
+          ),
+        ),
+      ),
+    );
+  }
+
+//* ▲▲▲▲▲▲▲▲ code ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//********************************************************************
+
+}

examples/api/lib/material/checkbox/checkbox.0.dart

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Template: dev/snippets/config/templates/stateful_widget_scaffold_center.tmpl
+//
+// Comment lines marked with "▼▼▼" and "▲▲▲" are used for authoring
+// of samples, and may be ignored if you are just exploring the sample.
+
+// Flutter code sample for Checkbox
+//
+//***************************************************************************
+//* ▼▼▼▼▼▼▼▼ description ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+// This example shows how you can override the default theme of
+// of a [Checkbox] with a [MaterialStateProperty].
+// In this example, the checkbox's color will be `Colors.blue` when the [Checkbox]
+// is being pressed, hovered, or focused. Otherwise, the checkbox's color will
+// be `Colors.red`.
+
+//* ▲▲▲▲▲▲▲▲ description ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//***************************************************************************
+
+import 'package:flutter/material.dart';
+
+void main() => runApp(const MyApp());
+
+/// This is the main application widget.
+class MyApp extends StatelessWidget {
+  const MyApp({Key? key}) : super(key: key);
+
+  static const String _title = 'Flutter Code Sample';
+
+  @override
+  Widget build(BuildContext context) {
+    return MaterialApp(
+      title: _title,
+      home: Scaffold(
+        appBar: AppBar(title: const Text(_title)),
+        body: const Center(
+          child: MyStatefulWidget(),
+        ),
+      ),
+    );
+  }
+}
+
+/// This is the stateful widget that the main application instantiates.
+class MyStatefulWidget extends StatefulWidget {
+  const MyStatefulWidget({Key? key}) : super(key: key);
+
+  @override
+  State<MyStatefulWidget> createState() => _MyStatefulWidgetState();
+}
+
+/// This is the private State class that goes with MyStatefulWidget.
+class _MyStatefulWidgetState extends State<MyStatefulWidget> {
+//********************************************************************
+//* ▼▼▼▼▼▼▼▼ code ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+  bool isChecked = false;
+
+  @override
+  Widget build(BuildContext context) {
+    Color getColor(Set<MaterialState> states) {
+      const Set<MaterialState> interactiveStates = <MaterialState>{
+        MaterialState.pressed,
+        MaterialState.hovered,
+        MaterialState.focused,
+      };
+      if (states.any(interactiveStates.contains)) {
+        return Colors.blue;
+      }
+      return Colors.red;
+    }
+
+    return Checkbox(
+      checkColor: Colors.white,
+      fillColor: MaterialStateProperty.resolveWith(getColor),
+      value: isChecked,
+      onChanged: (bool? value) {
+        setState(() {
+          isChecked = value!;
+        });
+      },
+    );
+  }
+
+//* ▲▲▲▲▲▲▲▲ code ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//********************************************************************
+
+}

examples/api/lib/material/checkbox_list_tile/checkbox_list_tile.0.dart

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Template: dev/snippets/config/templates/stateful_widget_scaffold_center.tmpl
+//
+// Comment lines marked with "▼▼▼" and "▲▲▲" are used for authoring
+// of samples, and may be ignored if you are just exploring the sample.
+
+// Flutter code sample for CheckboxListTile
+//
+//***************************************************************************
+//* ▼▼▼▼▼▼▼▼ description ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+// ![CheckboxListTile sample](https://flutter.github.io/assets-for-api-docs/assets/material/checkbox_list_tile.png)
+//
+// This widget shows a checkbox that, when checked, slows down all animations
+// (including the animation of the checkbox itself getting checked!).
+//
+// This sample requires that you also import 'package:flutter/scheduler.dart',
+// so that you can reference [timeDilation].
+
+//* ▲▲▲▲▲▲▲▲ description ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//***************************************************************************
+
+import 'package:flutter/material.dart';
+//****************************************************************************
+//* ▼▼▼▼▼▼▼▼ code-imports ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+import 'package:flutter/scheduler.dart' show timeDilation;
+
+//* ▲▲▲▲▲▲▲▲ code-imports ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//****************************************************************************
+
+void main() => runApp(const MyApp());
+
+/// This is the main application widget.
+class MyApp extends StatelessWidget {
+  const MyApp({Key? key}) : super(key: key);
+
+  static const String _title = 'Flutter Code Sample';
+
+  @override
+  Widget build(BuildContext context) {
+    return MaterialApp(
+      title: _title,
+      home: Scaffold(
+        appBar: AppBar(title: const Text(_title)),
+        body: const Center(
+          child: MyStatefulWidget(),
+        ),
+      ),
+    );
+  }
+}
+
+/// This is the stateful widget that the main application instantiates.
+class MyStatefulWidget extends StatefulWidget {
+  const MyStatefulWidget({Key? key}) : super(key: key);
+
+  @override
+  State<MyStatefulWidget> createState() => _MyStatefulWidgetState();
+}
+
+/// This is the private State class that goes with MyStatefulWidget.
+class _MyStatefulWidgetState extends State<MyStatefulWidget> {
+//********************************************************************
+//* ▼▼▼▼▼▼▼▼ code ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+  @override
+  Widget build(BuildContext context) {
+    return CheckboxListTile(
+      title: const Text('Animate Slowly'),
+      value: timeDilation != 1.0,
+      onChanged: (bool? value) {
+        setState(() {
+          timeDilation = value! ? 10.0 : 1.0;
+        });
+      },
+      secondary: const Icon(Icons.hourglass_empty),
+    );
+  }
+
+//* ▲▲▲▲▲▲▲▲ code ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//********************************************************************
+
+}

examples/api/lib/material/checkbox_list_tile/checkbox_list_tile.1.dart

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Template: dev/snippets/config/templates/stateful_widget_scaffold_center.tmpl
+//
+// Comment lines marked with "▼▼▼" and "▲▲▲" are used for authoring
+// of samples, and may be ignored if you are just exploring the sample.
+
+// Flutter code sample for CheckboxListTile
+//
+//***************************************************************************
+//* ▼▼▼▼▼▼▼▼ description ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+// ![Checkbox list tile semantics sample](https://flutter.github.io/assets-for-api-docs/assets/material/checkbox_list_tile_semantics.png)
+//
+// Here is an example of a custom labeled checkbox widget, called
+// LinkedLabelCheckbox, that includes an interactive [RichText] widget that
+// handles tap gestures.
+
+//* ▲▲▲▲▲▲▲▲ description ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//***************************************************************************
+
+//****************************************************************************
+//* ▼▼▼▼▼▼▼▼ code-imports ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+import 'package:flutter/gestures.dart';
+
+//* ▲▲▲▲▲▲▲▲ code-imports ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//****************************************************************************
+
+import 'package:flutter/material.dart';
+
+void main() => runApp(const MyApp());
+
+/// This is the main application widget.
+class MyApp extends StatelessWidget {
+  const MyApp({Key? key}) : super(key: key);
+
+  static const String _title = 'Flutter Code Sample';
+
+  @override
+  Widget build(BuildContext context) {
+    return MaterialApp(
+      title: _title,
+      home: Scaffold(
+        appBar: AppBar(title: const Text(_title)),
+        body: const Center(
+          child: MyStatefulWidget(),
+        ),
+      ),
+    );
+  }
+}
+
+//*****************************************************************************
+//* ▼▼▼▼▼▼▼▼ code-preamble ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+class LinkedLabelCheckbox extends StatelessWidget {
+  const LinkedLabelCheckbox({
+    Key? key,
+    required this.label,
+    required this.padding,
+    required this.value,
+    required this.onChanged,
+  }) : super(key: key);
+
+  final String label;
+  final EdgeInsets padding;
+  final bool value;
+  final ValueChanged<bool> onChanged;
+
+  @override
+  Widget build(BuildContext context) {
+    return Padding(
+      padding: padding,
+      child: Row(
+        children: <Widget>[
+          Expanded(
+            child: RichText(
+              text: TextSpan(
+                text: label,
+                style: const TextStyle(
+                  color: Colors.blueAccent,
+                  decoration: TextDecoration.underline,
+                ),
+                recognizer: TapGestureRecognizer()
+                  ..onTap = () {
+                    print('Label has been tapped.');
+                  },
+              ),
+            ),
+          ),
+          Checkbox(
+            value: value,
+            onChanged: (bool? newValue) {
+              onChanged(newValue!);
+            },
+          ),
+        ],
+      ),
+    );
+  }
+}
+
+//* ▲▲▲▲▲▲▲▲ code-preamble ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//*****************************************************************************
+
+/// This is the stateful widget that the main application instantiates.
+class MyStatefulWidget extends StatefulWidget {
+  const MyStatefulWidget({Key? key}) : super(key: key);
+
+  @override
+  State<MyStatefulWidget> createState() => _MyStatefulWidgetState();
+}
+
+/// This is the private State class that goes with MyStatefulWidget.
+class _MyStatefulWidgetState extends State<MyStatefulWidget> {
+//********************************************************************
+//* ▼▼▼▼▼▼▼▼ code ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+  bool _isSelected = false;
+
+  @override
+  Widget build(BuildContext context) {
+    return LinkedLabelCheckbox(
+      label: 'Linked, tappable label text',
+      padding: const EdgeInsets.symmetric(horizontal: 20.0),
+      value: _isSelected,
+      onChanged: (bool newValue) {
+        setState(() {
+          _isSelected = newValue;
+        });
+      },
+    );
+  }
+
+//* ▲▲▲▲▲▲▲▲ code ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//********************************************************************
+
+}

examples/api/lib/material/checkbox_list_tile/checkbox_list_tile.2.dart

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Template: dev/snippets/config/templates/stateful_widget_scaffold_center.tmpl
+//
+// Comment lines marked with "▼▼▼" and "▲▲▲" are used for authoring
+// of samples, and may be ignored if you are just exploring the sample.
+
+// Flutter code sample for CheckboxListTile
+//
+//***************************************************************************
+//* ▼▼▼▼▼▼▼▼ description ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+// ![Custom checkbox list tile sample](https://flutter.github.io/assets-for-api-docs/assets/material/checkbox_list_tile_custom.png)
+//
+// Here is an example of a custom LabeledCheckbox widget, but you can easily
+// make your own configurable widget.
+
+//* ▲▲▲▲▲▲▲▲ description ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//***************************************************************************
+
+import 'package:flutter/material.dart';
+
+void main() => runApp(const MyApp());
+
+/// This is the main application widget.
+class MyApp extends StatelessWidget {
+  const MyApp({Key? key}) : super(key: key);
+
+  static const String _title = 'Flutter Code Sample';
+
+  @override
+  Widget build(BuildContext context) {
+    return MaterialApp(
+      title: _title,
+      home: Scaffold(
+        appBar: AppBar(title: const Text(_title)),
+        body: const Center(
+          child: MyStatefulWidget(),
+        ),
+      ),
+    );
+  }
+}
+
+//*****************************************************************************
+//* ▼▼▼▼▼▼▼▼ code-preamble ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+class LabeledCheckbox extends StatelessWidget {
+  const LabeledCheckbox({
+    Key? key,
+    required this.label,
+    required this.padding,
+    required this.value,
+    required this.onChanged,
+  }) : super(key: key);
+
+  final String label;
+  final EdgeInsets padding;
+  final bool value;
+  final ValueChanged<bool> onChanged;
+
+  @override
+  Widget build(BuildContext context) {
+    return InkWell(
+      onTap: () {
+        onChanged(!value);
+      },
+      child: Padding(
+        padding: padding,
+        child: Row(
+          children: <Widget>[
+            Expanded(child: Text(label)),
+            Checkbox(
+              value: value,
+              onChanged: (bool? newValue) {
+                onChanged(newValue!);
+              },
+            ),
+          ],
+        ),
+      ),
+    );
+  }
+}
+
+//* ▲▲▲▲▲▲▲▲ code-preamble ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//*****************************************************************************
+
+/// This is the stateful widget that the main application instantiates.
+class MyStatefulWidget extends StatefulWidget {
+  const MyStatefulWidget({Key? key}) : super(key: key);
+
+  @override
+  State<MyStatefulWidget> createState() => _MyStatefulWidgetState();
+}
+
+/// This is the private State class that goes with MyStatefulWidget.
+class _MyStatefulWidgetState extends State<MyStatefulWidget> {
+//********************************************************************
+//* ▼▼▼▼▼▼▼▼ code ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+  bool _isSelected = false;
+
+  @override
+  Widget build(BuildContext context) {
+    return LabeledCheckbox(
+      label: 'This is the label text',
+      padding: const EdgeInsets.symmetric(horizontal: 20.0),
+      value: _isSelected,
+      onChanged: (bool newValue) {
+        setState(() {
+          _isSelected = newValue;
+        });
+      },
+    );
+  }
+
+//* ▲▲▲▲▲▲▲▲ code ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//********************************************************************
+
+}

examples/api/lib/material/chip/deletable_chip_attributes.on_deleted.0.dart

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Template: dev/snippets/config/templates/stateful_widget_scaffold_center.tmpl
+//
+// Comment lines marked with "▼▼▼" and "▲▲▲" are used for authoring
+// of samples, and may be ignored if you are just exploring the sample.
+
+// Flutter code sample for DeletableChipAttributes.onDeleted
+//
+//***************************************************************************
+//* ▼▼▼▼▼▼▼▼ description ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+// This sample shows how to use [onDeleted] to remove an entry when the
+// delete button is tapped.
+
+//* ▲▲▲▲▲▲▲▲ description ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//***************************************************************************
+
+import 'package:flutter/material.dart';
+
+void main() => runApp(const MyApp());
+
+/// This is the main application widget.
+class MyApp extends StatelessWidget {
+  const MyApp({Key? key}) : super(key: key);
+
+  static const String _title = 'Flutter Code Sample';
+
+  @override
+  Widget build(BuildContext context) {
+    return MaterialApp(
+      title: _title,
+      home: Scaffold(
+        appBar: AppBar(title: const Text(_title)),
+        body: const Center(
+          child: MyStatefulWidget(),
+        ),
+      ),
+    );
+  }
+}
+
+//*****************************************************************************
+//* ▼▼▼▼▼▼▼▼ code-preamble ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+class Actor {
+  const Actor(this.name, this.initials);
+  final String name;
+  final String initials;
+}
+
+class CastList extends StatefulWidget {
+  const CastList({Key? key}) : super(key: key);
+
+  @override
+  State createState() => CastListState();
+}
+
+class CastListState extends State<CastList> {
+  final List<Actor> _cast = <Actor>[
+    const Actor('Aaron Burr', 'AB'),
+    const Actor('Alexander Hamilton', 'AH'),
+    const Actor('Eliza Hamilton', 'EH'),
+    const Actor('James Madison', 'JM'),
+  ];
+
+  Iterable<Widget> get actorWidgets sync* {
+    for (final Actor actor in _cast) {
+      yield Padding(
+        padding: const EdgeInsets.all(4.0),
+        child: Chip(
+          avatar: CircleAvatar(child: Text(actor.initials)),
+          label: Text(actor.name),
+          onDeleted: () {
+            setState(() {
+              _cast.removeWhere((Actor entry) {
+                return entry.name == actor.name;
+              });
+            });
+          },
+        ),
+      );
+    }
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return Wrap(
+      children: actorWidgets.toList(),
+    );
+  }
+}
+
+//* ▲▲▲▲▲▲▲▲ code-preamble ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//*****************************************************************************
+
+/// This is the stateful widget that the main application instantiates.
+class MyStatefulWidget extends StatefulWidget {
+  const MyStatefulWidget({Key? key}) : super(key: key);
+
+  @override
+  State<MyStatefulWidget> createState() => _MyStatefulWidgetState();
+}
+
+/// This is the private State class that goes with MyStatefulWidget.
+class _MyStatefulWidgetState extends State<MyStatefulWidget> {
+//********************************************************************
+//* ▼▼▼▼▼▼▼▼ code ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+  @override
+  Widget build(BuildContext context) {
+    return const CastList();
+  }
+
+//* ▲▲▲▲▲▲▲▲ code ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//********************************************************************
+
+}

examples/api/lib/material/data_table/data_table.0.dart

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Template: dev/snippets/config/templates/stateless_widget_scaffold.tmpl
+//
+// Comment lines marked with "▼▼▼" and "▲▲▲" are used for authoring
+// of samples, and may be ignored if you are just exploring the sample.
+
+// Flutter code sample for DataTable
+//
+//***************************************************************************
+//* ▼▼▼▼▼▼▼▼ description ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+// This sample shows how to display a [DataTable] with three columns: name, age, and
+// role. The columns are defined by three [DataColumn] objects. The table
+// contains three rows of data for three example users, the data for which
+// is defined by three [DataRow] objects.
+//
+// ![](https://flutter.github.io/assets-for-api-docs/assets/material/data_table.png)
+
+//* ▲▲▲▲▲▲▲▲ description ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//***************************************************************************
+
+import 'package:flutter/material.dart';
+
+void main() => runApp(const MyApp());
+
+/// This is the main application widget.
+class MyApp extends StatelessWidget {
+  const MyApp({Key? key}) : super(key: key);
+
+  static const String _title = 'Flutter Code Sample';
+
+  @override
+  Widget build(BuildContext context) {
+    return MaterialApp(
+      title: _title,
+      home: Scaffold(
+        appBar: AppBar(title: const Text(_title)),
+        body: const MyStatelessWidget(),
+      ),
+    );
+  }
+}
+
+/// This is the stateless widget that the main application instantiates.
+class MyStatelessWidget extends StatelessWidget {
+  const MyStatelessWidget({Key? key}) : super(key: key);
+
+  @override
+//********************************************************************
+//* ▼▼▼▼▼▼▼▼ code ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+  Widget build(BuildContext context) {
+    return DataTable(
+      columns: const <DataColumn>[
+        DataColumn(
+          label: Text(
+            'Name',
+            style: TextStyle(fontStyle: FontStyle.italic),
+          ),
+        ),
+        DataColumn(
+          label: Text(
+            'Age',
+            style: TextStyle(fontStyle: FontStyle.italic),
+          ),
+        ),
+        DataColumn(
+          label: Text(
+            'Role',
+            style: TextStyle(fontStyle: FontStyle.italic),
+          ),
+        ),
+      ],
+      rows: const <DataRow>[
+        DataRow(
+          cells: <DataCell>[
+            DataCell(Text('Sarah')),
+            DataCell(Text('19')),
+            DataCell(Text('Student')),
+          ],
+        ),
+        DataRow(
+          cells: <DataCell>[
+            DataCell(Text('Janine')),
+            DataCell(Text('43')),
+            DataCell(Text('Professor')),
+          ],
+        ),
+        DataRow(
+          cells: <DataCell>[
+            DataCell(Text('William')),
+            DataCell(Text('27')),
+            DataCell(Text('Associate Professor')),
+          ],
+        ),
+      ],
+    );
+  }
+
+//* ▲▲▲▲▲▲▲▲ code ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//********************************************************************
+
+}

examples/api/lib/material/data_table/data_table.1.dart

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Template: dev/snippets/config/templates/stateful_widget_scaffold.tmpl
+//
+// Comment lines marked with "▼▼▼" and "▲▲▲" are used for authoring
+// of samples, and may be ignored if you are just exploring the sample.
+
+// Flutter code sample for DataTable
+//
+//***************************************************************************
+//* ▼▼▼▼▼▼▼▼ description ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+// This sample shows how to display a [DataTable] with alternate colors per
+// row, and a custom color for when the row is selected.
+
+//* ▲▲▲▲▲▲▲▲ description ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//***************************************************************************
+
+import 'package:flutter/material.dart';
+
+void main() => runApp(const MyApp());
+
+/// This is the main application widget.
+class MyApp extends StatelessWidget {
+  const MyApp({Key? key}) : super(key: key);
+
+  static const String _title = 'Flutter Code Sample';
+
+  @override
+  Widget build(BuildContext context) {
+    return MaterialApp(
+      title: _title,
+      home: Scaffold(
+        appBar: AppBar(title: const Text(_title)),
+        body: const MyStatefulWidget(),
+      ),
+    );
+  }
+}
+
+/// This is the stateful widget that the main application instantiates.
+class MyStatefulWidget extends StatefulWidget {
+  const MyStatefulWidget({Key? key}) : super(key: key);
+
+  @override
+  State<MyStatefulWidget> createState() => _MyStatefulWidgetState();
+}
+
+/// This is the private State class that goes with MyStatefulWidget.
+class _MyStatefulWidgetState extends State<MyStatefulWidget> {
+//********************************************************************
+//* ▼▼▼▼▼▼▼▼ code ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+  static const int numItems = 10;
+  List<bool> selected = List<bool>.generate(numItems, (int index) => false);
+
+  @override
+  Widget build(BuildContext context) {
+    return SizedBox(
+      width: double.infinity,
+      child: DataTable(
+        columns: const <DataColumn>[
+          DataColumn(
+            label: Text('Number'),
+          ),
+        ],
+        rows: List<DataRow>.generate(
+          numItems,
+          (int index) => DataRow(
+            color: MaterialStateProperty.resolveWith<Color?>(
+                (Set<MaterialState> states) {
+              // All rows will have the same selected color.
+              if (states.contains(MaterialState.selected)) {
+                return Theme.of(context).colorScheme.primary.withOpacity(0.08);
+              }
+              // Even rows will have a grey color.
+              if (index.isEven) {
+                return Colors.grey.withOpacity(0.3);
+              }
+              return null; // Use default value for other states and odd rows.
+            }),
+            cells: <DataCell>[DataCell(Text('Row $index'))],
+            selected: selected[index],
+            onSelectChanged: (bool? value) {
+              setState(() {
+                selected[index] = value!;
+              });
+            },
+          ),
+        ),
+      ),
+    );
+  }
+
+//* ▲▲▲▲▲▲▲▲ code ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//********************************************************************
+
+}

examples/api/lib/material/date_picker/show_date_picker.0.dart

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Template: dev/snippets/config/templates/stateful_widget_restoration_material.tmpl
+//
+// Comment lines marked with "▼▼▼" and "▲▲▲" are used for authoring
+// of samples, and may be ignored if you are just exploring the sample.
+
+// Flutter code sample for showDatePicker
+//
+//***************************************************************************
+//* ▼▼▼▼▼▼▼▼ description ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+// This sample demonstrates how to create a restorable Material date picker.
+// This is accomplished by enabling state restoration by specifying
+// [MaterialApp.restorationScopeId] and using [Navigator.restorablePush] to
+// push [DatePickerDialog] when the button is tapped.
+
+//* ▲▲▲▲▲▲▲▲ description ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//***************************************************************************
+
+import 'package:flutter/material.dart';
+
+void main() => runApp(const MyApp());
+
+/// This is the main application widget.
+class MyApp extends StatelessWidget {
+  const MyApp({Key? key}) : super(key: key);
+
+  static const String _title = 'Flutter Code Sample';
+
+  @override
+  Widget build(BuildContext context) {
+    return const MaterialApp(
+      restorationScopeId: 'app',
+      title: _title,
+      home: MyStatefulWidget(restorationId: 'main'),
+    );
+  }
+}
+
+/// This is the stateful widget that the main application instantiates.
+class MyStatefulWidget extends StatefulWidget {
+  const MyStatefulWidget({Key? key, this.restorationId}) : super(key: key);
+
+  final String? restorationId;
+
+  @override
+  State<MyStatefulWidget> createState() => _MyStatefulWidgetState();
+}
+
+/// This is the private State class that goes with MyStatefulWidget.
+/// RestorationProperty objects can be used because of RestorationMixin.
+class _MyStatefulWidgetState extends State<MyStatefulWidget>
+    with RestorationMixin {
+  // In this example, the restoration ID for the mixin is passed in through
+  // the [StatefulWidget]'s constructor.
+  @override
+  String? get restorationId => widget.restorationId;
+
+//********************************************************************
+//* ▼▼▼▼▼▼▼▼ code ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+  final RestorableDateTime _selectedDate =
+      RestorableDateTime(DateTime(2021, 7, 25));
+  late final RestorableRouteFuture<DateTime?> _restorableDatePickerRouteFuture =
+      RestorableRouteFuture<DateTime?>(
+    onComplete: _selectDate,
+    onPresent: (NavigatorState navigator, Object? arguments) {
+      return navigator.restorablePush(
+        _datePickerRoute,
+        arguments: _selectedDate.value.millisecondsSinceEpoch,
+      );
+    },
+  );
+
+  static Route<DateTime> _datePickerRoute(
+    BuildContext context,
+    Object? arguments,
+  ) {
+    return DialogRoute<DateTime>(
+      context: context,
+      builder: (BuildContext context) {
+        return DatePickerDialog(
+          restorationId: 'date_picker_dialog',
+          initialEntryMode: DatePickerEntryMode.calendarOnly,
+          initialDate: DateTime.fromMillisecondsSinceEpoch(arguments! as int),
+          firstDate: DateTime(2021, 1, 1),
+          lastDate: DateTime(2022, 1, 1),
+        );
+      },
+    );
+  }
+
+  @override
+  void restoreState(RestorationBucket? oldBucket, bool initialRestore) {
+    registerForRestoration(_selectedDate, 'selected_date');
+    registerForRestoration(
+        _restorableDatePickerRouteFuture, 'date_picker_route_future');
+  }
+
+  void _selectDate(DateTime? newSelectedDate) {
+    if (newSelectedDate != null) {
+      setState(() {
+        _selectedDate.value = newSelectedDate;
+        ScaffoldMessenger.of(context).showSnackBar(SnackBar(
+          content: Text(
+              'Selected: ${_selectedDate.value.day}/${_selectedDate.value.month}/${_selectedDate.value.year}'),
+        ));
+      });
+    }
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      body: Center(
+        child: OutlinedButton(
+          onPressed: () {
+            _restorableDatePickerRouteFuture.present();
+          },
+          child: const Text('Open Date Picker'),
+        ),
+      ),
+    );
+  }
+
+//* ▲▲▲▲▲▲▲▲ code ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//********************************************************************
+
+}

examples/api/lib/material/dialog/alert_dialog.1.dart

+// Copyright 2014 The Flutter Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// Template: dev/snippets/config/templates/stateless_widget_scaffold_center.tmpl
+//
+// Comment lines marked with "▼▼▼" and "▲▲▲" are used for authoring
+// of samples, and may be ignored if you are just exploring the sample.
+
+// Flutter code sample for AlertDialog
+//
+//***************************************************************************
+//* ▼▼▼▼▼▼▼▼ description ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+// This demo shows a [TextButton] which when pressed, calls [showDialog]. When called, this method
+// displays a Material dialog above the current contents of the app and returns
+// a [Future] that completes when the dialog is dismissed.
+
+//* ▲▲▲▲▲▲▲▲ description ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//***************************************************************************
+
+import 'package:flutter/material.dart';
+
+void main() => runApp(const MyApp());
+
+/// This is the main application widget.
+class MyApp extends StatelessWidget {
+  const MyApp({Key? key}) : super(key: key);
+
+  static const String _title = 'Flutter Code Sample';
+
+  @override
+  Widget build(BuildContext context) {
+    return MaterialApp(
+      title: _title,
+      home: Scaffold(
+        appBar: AppBar(title: const Text(_title)),
+        body: const Center(
+          child: MyStatelessWidget(),
+        ),
+      ),
+    );
+  }
+}
+
+/// This is the stateless widget that the main application instantiates.
+class MyStatelessWidget extends StatelessWidget {
+  const MyStatelessWidget({Key? key}) : super(key: key);
+
+  @override
+//********************************************************************
+//* ▼▼▼▼▼▼▼▼ code ▼▼▼▼▼▼▼▼ (do not modify or remove section marker)
+
+  Widget build(BuildContext context) {
+    return TextButton(
+      onPressed: () => showDialog<String>(
+        context: context,
+        builder: (BuildContext context) => AlertDialog(
+          title: const Text('AlertDialog Title'),
+          content: const Text('AlertDialog description'),
+          actions: <Widget>[
+            TextButton(
+              onPressed: () => Navigator.pop(context, 'Cancel'),
+              child: const Text('Cancel'),
+            ),
+            TextButton(
+              onPressed: () => Navigator.pop(context, 'OK'),
+              child: const Text('OK'),
+            ),
+          ],
+        ),
+      ),
+      child: const Text('Show Dialog'),
+    );
+  }
+
+//* ▲▲▲▲▲▲▲▲ code ▲▲▲▲▲▲▲▲ (do not modify or remove section marker)
+//********************************************************************
+
+}