Autocomplete dartpad examples fix (#77863)

Fixes the dartpad examples on the docs site.

packages/flutter/lib/src/material/autocomplete.dart

@@ -14,15 +14,33 @@ import 'text_form_field.dart';
 /// This example shows how to create a very basic Autocomplete widget using the
 /// default UI.
 ///
-/// ```dart imports
+/// ```dart main
 /// import 'package:flutter/material.dart';
-/// ```
 ///
-/// ```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 {
-///   AutocompleteBasicExample({Key? key}) : super(key: key);
+///   const AutocompleteBasicExample({Key? key}) : super(key: key);
 ///
-///   final List<String> _kOptions = <String>[
+///   static const List<String> _kOptions = <String>[
 ///     'aardvark',
 ///     'bobcat',
 ///     'chameleon',
@@ -52,11 +70,29 @@ import 'text_form_field.dart';
 /// This example shows how to create an Autocomplete widget with a custom type.
 /// Try searching with text from the name or email field.
 ///
-/// ```dart imports
+/// ```dart main
 /// import 'package:flutter/material.dart';
-/// ```
 ///
-/// ```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({

packages/flutter/lib/src/widgets/autocomplete.dart

@@ -78,12 +78,30 @@ typedef AutocompleteOptionToString<T extends Object> = String Function(T option)
 /// This example shows how to create a very basic autocomplete widget using the
 /// [fieldViewBuilder] and [optionsViewBuilder] parameters.
 ///
-/// ```dart imports
-/// import 'package:flutter/widgets.dart';
+/// ```dart main
 /// import 'package:flutter/material.dart';
-/// ```
+/// import 'package:flutter/widgets.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('RawAutocomplete Basic'),
+///         ),
+///         body: const Center(
+///           child: AutocompleteBasicExample(),
+///         ),
+///       ),
+///     );
+///   }
+/// }
 ///
-/// ```dart
 /// class AutocompleteBasicExample extends StatelessWidget {
 ///   const AutocompleteBasicExample({Key? key}) : super(key: key);
 ///
@@ -152,12 +170,30 @@ typedef AutocompleteOptionToString<T extends Object> = String Function(T option)
 /// This example is similar to the previous example, but it uses a custom T data
 /// type instead of directly using String.
 ///
-/// ```dart imports
-/// import 'package:flutter/widgets.dart';
+/// ```dart main
 /// import 'package:flutter/material.dart';
-/// ```
+/// import 'package:flutter/widgets.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('RawAutocomplete Custom Type'),
+///         ),
+///         body: const Center(
+///           child: AutocompleteCustomTypeExample(),
+///         ),
+///       ),
+///     );
+///   }
+/// }
 ///
-/// ```dart
 /// // An example of a type that someone might want to autocomplete a list of.
 /// @immutable
 /// class User {
@@ -254,26 +290,44 @@ typedef AutocompleteOptionToString<T extends Object> = String Function(T option)
 /// {@tool dartpad --template=freeform}
 /// This example shows the use of RawAutocomplete in a form.
 ///
-/// ```dart imports
-/// import 'package:flutter/widgets.dart';
+/// ```dart main
 /// import 'package:flutter/material.dart';
-/// ```
+/// import 'package:flutter/widgets.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('RawAutocomplete Form'),
+///         ),
+///         body: const Center(
+///           child: AutocompleteFormExample(),
+///         ),
+///       ),
+///     );
+///   }
+/// }
 ///
-/// ```dart
-/// class AutocompleteFormExamplePage extends StatefulWidget {
-///   const AutocompleteFormExamplePage({Key? key}) : super(key: key);
+/// class AutocompleteFormExample extends StatefulWidget {
+///   const AutocompleteFormExample({Key? key}) : super(key: key);
 ///
 ///   @override
-///   AutocompleteFormExample createState() => AutocompleteFormExample();
+///   AutocompleteFormExampleState createState() => AutocompleteFormExampleState();
 /// }
 ///
-/// class AutocompleteFormExample extends State<AutocompleteFormExamplePage> {
+/// class AutocompleteFormExampleState extends State<AutocompleteFormExample> {
 ///   final GlobalKey<FormState> _formKey = GlobalKey<FormState>();
 ///   final TextEditingController _textEditingController = TextEditingController();
 ///   String? _dropdownValue;
 ///   String? _autocompleteSelection;
 ///
-///   final List<String> _options = <String>[
+///   static const List<String> _options = <String>[
 ///     'aardvark',
 ///     'bobcat',
 ///     'chameleon',
@@ -281,12 +335,7 @@ typedef AutocompleteOptionToString<T extends Object> = String Function(T option)
 ///
 ///   @override
 ///   Widget build(BuildContext context) {
-///     return Scaffold(
-///       appBar: AppBar(
-///         title: const Text('Autocomplete Form Example'),
-///       ),
-///       body: Center(
-///         child: Form(
+///     return Form(
 ///       key: _formKey,
 ///       child: Column(
 ///         children: <Widget>[
@@ -343,7 +392,7 @@ typedef AutocompleteOptionToString<T extends Object> = String Function(T option)
 ///               return TextFormField(
 ///                 controller: textEditingController,
 ///                 decoration: const InputDecoration(
-///                       hintText: 'This is an RawAutocomplete!',
+///                   hintText: 'This is a RawAutocomplete!',
 ///                 ),
 ///                 focusNode: focusNode,
 ///                 onFieldSubmitted: (String value) {
@@ -420,8 +469,6 @@ typedef AutocompleteOptionToString<T extends Object> = String Function(T option)
 ///           ),
 ///         ],
 ///       ),
-///         ),
-///       ),
 ///     );
 ///   }
 /// }
@@ -483,38 +530,44 @@ class RawAutocomplete<T extends Object> extends StatefulWidget {
   /// This examples shows how to create an autocomplete widget with the text
   /// field in the AppBar and the results in the main body of the app.
   ///
-  /// ```dart imports
-  /// import 'package:flutter/widgets.dart';
+  /// ```dart main
   /// import 'package:flutter/material.dart';
-  /// ```
+  /// import 'package:flutter/widgets.dart';
+  ///
+  /// void main() => runApp(const AutocompleteExampleApp());
   ///
-  /// ```dart
-  /// final List<String> _options = <String>[
+  /// class AutocompleteExampleApp extends StatelessWidget {
+  ///   const AutocompleteExampleApp({Key? key}) : super(key: key);
+  ///
+  ///   @override
+  ///   Widget build(BuildContext context) {
+  ///     return const MaterialApp(
+  ///       home: RawAutocompleteSplit(),
+  ///     );
+  ///   }
+  /// }
+  ///
+  /// const List<String> _options = <String>[
   ///   'aardvark',
   ///   'bobcat',
   ///   'chameleon',
   /// ];
   ///
-  /// class RawAutocompleteSplitPage extends StatefulWidget {
-  ///   const RawAutocompleteSplitPage({Key? key}) : super(key: key);
+  /// class RawAutocompleteSplit extends StatefulWidget {
+  ///   const RawAutocompleteSplit({Key? key}) : super(key: key);
   ///
   ///   @override
-  ///   RawAutocompleteSplitPageState createState() => RawAutocompleteSplitPageState();
+  ///   RawAutocompleteSplitState createState() => RawAutocompleteSplitState();
   /// }
   ///
-  /// class RawAutocompleteSplitPageState extends State<RawAutocompleteSplitPage> {
+  /// class RawAutocompleteSplitState extends State<RawAutocompleteSplit> {
   ///   final TextEditingController _textEditingController = TextEditingController();
   ///   final FocusNode _focusNode = FocusNode();
   ///   final GlobalKey _autocompleteKey = GlobalKey();
   ///
   ///   @override
   ///   Widget build(BuildContext context) {
-  ///     return MaterialApp(
-  ///       theme: ThemeData(
-  ///         primarySwatch: Colors.blue,
-  ///       ),
-  ///       title: 'Split RawAutocomplete App',
-  ///       home: Scaffold(
+  ///     return Scaffold(
   ///       appBar: AppBar(
   ///         // This is where the real field is being built.
   ///         title: TextFormField(
@@ -556,7 +609,6 @@ class RawAutocomplete<T extends Object> extends StatefulWidget {
   ///           },
   ///         ),
   ///       ),
-  ///       ),
   ///     );
   ///   }
   /// }