Let MaterialApp/CupertinoApp provide default cupertino localization (#22706)

packages/flutter/lib/src/cupertino/app.dart

@@ -8,6 +8,7 @@ import 'package:flutter/widgets.dart';
 import 'button.dart';
 import 'colors.dart';
 import 'icons.dart';
+import 'localizations.dart';
 import 'route.dart';
 
 // Based on specs from https://developer.apple.com/design/resources/ for
@@ -246,6 +247,17 @@ class _CupertinoAppState extends State<CupertinoApp> {
     }
   }
 
+  // Combine the default localization for Cupertino with the ones contributed
+  // by the localizationsDelegates parameter, if any. Only the first delegate
+  // of a particular LocalizationsDelegate.type is loaded so the
+  // localizationsDelegate parameter can be used to override
+  // _CupertinoLocalizationsDelegate.
+  Iterable<LocalizationsDelegate<dynamic>> get _localizationsDelegates sync* {
+    if (widget.localizationsDelegates != null)
+      yield* widget.localizationsDelegates;
+    yield DefaultCupertinoLocalizations.delegate;
+  }
+
   @override
   Widget build(BuildContext context) {
     return ScrollConfiguration(
@@ -269,7 +281,7 @@ class _CupertinoAppState extends State<CupertinoApp> {
         textStyle: _kDefaultTextStyle,
         color: widget.color ?? CupertinoColors.activeBlue,
         locale: widget.locale,
-        localizationsDelegates: widget.localizationsDelegates,
+        localizationsDelegates: _localizationsDelegates,
         localeResolutionCallback: widget.localeResolutionCallback,
         supportedLocales: widget.supportedLocales,
         showPerformanceOverlay: widget.showPerformanceOverlay,

packages/flutter/lib/src/cupertino/date_picker.dart

@@ -397,7 +397,7 @@ class _CupertinoDatePickerDateTimeState extends State<CupertinoDatePicker> {
     super.didChangeDependencies();
 
     textDirectionFactor = Directionality.of(context) == TextDirection.ltr ? 1 : -1;
-    localizations = CupertinoLocalizations.of(context) ?? const DefaultCupertinoLocalizations();
+    localizations = CupertinoLocalizations.of(context);
 
     alignCenterLeft = textDirectionFactor == 1 ? Alignment.centerLeft : Alignment.centerRight;
     alignCenterRight = textDirectionFactor == 1 ? Alignment.centerRight : Alignment.centerLeft;
@@ -694,7 +694,7 @@ class _CupertinoDatePickerDateState extends State<CupertinoDatePicker> {
     super.didChangeDependencies();
 
     textDirectionFactor = Directionality.of(context) == TextDirection.ltr ? 1 : -1;
-    localizations = CupertinoLocalizations.of(context) ?? const DefaultCupertinoLocalizations();
+    localizations = CupertinoLocalizations.of(context);
 
     alignCenterLeft = textDirectionFactor == 1 ? Alignment.centerLeft : Alignment.centerRight;
     alignCenterRight = textDirectionFactor == 1 ? Alignment.centerRight : Alignment.centerLeft;
@@ -1033,7 +1033,7 @@ class _CupertinoTimerPickerState extends State<CupertinoTimerPicker> {
     super.didChangeDependencies();
 
     textDirectionFactor = Directionality.of(context) == TextDirection.ltr ? 1 : -1;
-    localizations = CupertinoLocalizations.of(context) ?? const DefaultCupertinoLocalizations();
+    localizations = CupertinoLocalizations.of(context);
 
     alignCenterLeft = textDirectionFactor == 1 ? Alignment.centerLeft : Alignment.centerRight;
     alignCenterRight = textDirectionFactor == 1 ? Alignment.centerRight : Alignment.centerLeft;

packages/flutter/lib/src/cupertino/dialog.dart

@@ -219,8 +219,7 @@ class CupertinoAlertDialog extends StatelessWidget {
 
   @override
   Widget build(BuildContext context) {
-    final CupertinoLocalizations localizations = CupertinoLocalizations.of(context)
-                                              ?? const DefaultCupertinoLocalizations();
+    final CupertinoLocalizations localizations = CupertinoLocalizations.of(context);
     final bool isInAccessibilityMode = _isInAccessibilityMode(context);
     final double textScaleFactor = MediaQuery.of(context).textScaleFactor;
     return MediaQuery(

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

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+import 'package:flutter/cupertino.dart';
 import 'package:flutter/rendering.dart';
 import 'package:flutter/widgets.dart';
 
@@ -366,6 +367,7 @@ class _MaterialAppState extends State<MaterialApp> {
     if (widget.localizationsDelegates != null)
       yield* widget.localizationsDelegates;
     yield DefaultMaterialLocalizations.delegate;
+    yield DefaultCupertinoLocalizations.delegate;
   }
 
   @override

packages/flutter/test/cupertino/app_test.dart

@@ -40,4 +40,26 @@ void main() {
     expect(find.widgetWithText(CupertinoPageRoute, 'foo'), findsNothing);
     expect(find.widgetWithText(Navigator, 'foo'), findsOneWidget);
   });
+
+  testWidgets('Has default cupertino localizations', (WidgetTester tester) async {
+    await tester.pumpWidget(
+      CupertinoApp(
+        home: Builder(
+          builder: (BuildContext context) {
+            return Column(
+              children: <Widget>[
+                Text(CupertinoLocalizations.of(context).selectAllButtonLabel),
+                Text(CupertinoLocalizations.of(context).datePickerMediumDate(
+                  DateTime(2018, 10, 4),
+                )),
+              ],
+            );
+          },
+        ),
+      ),
+    );
+
+    expect(find.text('Select All'), findsOneWidget);
+    expect(find.text('Thu Oct 4 '), findsOneWidget);
+  });
 }

packages/flutter/test/cupertino/date_picker_test.dart

@@ -99,9 +99,8 @@ void main() {
 
     testWidgets('columns are ordered correctly when text direction is ltr', (WidgetTester tester) async {
       await tester.pumpWidget(
-        Directionality(
-          textDirection: TextDirection.ltr,
-          child: CupertinoTimerPicker(
+        CupertinoApp(
+          home: CupertinoTimerPicker(
             onTimerDurationChanged: (_) {},
             initialTimerDuration: const Duration(hours: 12, minutes: 30, seconds: 59),
           ),
@@ -127,13 +126,15 @@ void main() {
 
     testWidgets('columns are ordered correctly when text direction is rtl', (WidgetTester tester) async {
       await tester.pumpWidget(
-        Directionality(
+        CupertinoApp(
+          home: Directionality(
             textDirection: TextDirection.rtl,
             child: CupertinoTimerPicker(
               onTimerDurationChanged: (_) {},
               initialTimerDuration: const Duration(hours: 12, minutes: 30, seconds: 59),
             ),
           ),
+        ),
       );
 
       Offset lastOffset = tester.getTopLeft(find.text('12'));
@@ -155,11 +156,10 @@ void main() {
 
     testWidgets('width of picker is consistent', (WidgetTester tester) async {
       await tester.pumpWidget(
-        SizedBox(
+        CupertinoApp(
+          home: SizedBox(
             height: 400.0,
             width: 400.0,
-          child: Directionality(
-            textDirection: TextDirection.ltr,
             child: CupertinoTimerPicker(
               onTimerDurationChanged: (_) {},
               initialTimerDuration: const Duration(hours: 12, minutes: 30, seconds: 59),
@@ -173,11 +173,10 @@ void main() {
         tester.getCenter(find.text('sec')).dx - tester.getCenter(find.text('12')).dx;
 
       await tester.pumpWidget(
-        SizedBox(
+        CupertinoApp(
+          home: SizedBox(
             height: 400.0,
             width: 800.0,
-          child: Directionality(
-            textDirection: TextDirection.ltr,
             child: CupertinoTimerPicker(
               onTimerDurationChanged: (_) {},
               initialTimerDuration: const Duration(hours: 12, minutes: 30, seconds: 59),
@@ -246,11 +245,10 @@ void main() {
     testWidgets('changing initialDateTime after first build does not do anything', (WidgetTester tester) async {
       DateTime selectedDateTime;
       await tester.pumpWidget(
-        SizedBox(
+        CupertinoApp(
+          home: SizedBox(
             height: 400.0,
             width: 400.0,
-          child: Directionality(
-            textDirection: TextDirection.ltr,
             child: CupertinoDatePicker(
               mode: CupertinoDatePickerMode.dateAndTime,
               onDateTimeChanged: (DateTime dateTime) => selectedDateTime = dateTime,
@@ -267,11 +265,10 @@ void main() {
       expect(selectedDateTime, DateTime(2018, 1, 1, 9, 30));
 
       await tester.pumpWidget(
-        SizedBox(
+        CupertinoApp(
+          home: SizedBox(
             height: 400.0,
             width: 400.0,
-          child: Directionality(
-            textDirection: TextDirection.ltr,
             child: CupertinoDatePicker(
               mode: CupertinoDatePickerMode.dateAndTime,
               onDateTimeChanged: (DateTime dateTime) => selectedDateTime = dateTime,
@@ -292,11 +289,10 @@ void main() {
 
     testWidgets('date picker has expected string', (WidgetTester tester) async {
       await tester.pumpWidget(
-        SizedBox(
+        CupertinoApp(
+          home: SizedBox(
             height: 400.0,
             width: 400.0,
-          child: Directionality(
-            textDirection: TextDirection.ltr,
             child: CupertinoDatePicker(
               mode: CupertinoDatePickerMode.date,
               onDateTimeChanged: (_) {},
@@ -313,11 +309,10 @@ void main() {
 
     testWidgets('datetime picker has expected string', (WidgetTester tester) async {
       await tester.pumpWidget(
-        SizedBox(
+        CupertinoApp(
+          home: SizedBox(
             height: 400.0,
             width: 400.0,
-          child: Directionality(
-            textDirection: TextDirection.ltr,
             child: CupertinoDatePicker(
               mode: CupertinoDatePickerMode.dateAndTime,
               onDateTimeChanged: (_) {},
@@ -335,10 +330,8 @@ void main() {
 
     testWidgets('width of picker in date and time mode is consistent', (WidgetTester tester) async {
       await tester.pumpWidget(
-        SizedBox(
-          height: 400.0,
-          width: 400.0,
-          child: Directionality(
+        CupertinoApp(
+          home: Directionality(
             textDirection: TextDirection.ltr,
             child: CupertinoDatePicker(
               mode: CupertinoDatePickerMode.dateAndTime,
@@ -354,11 +347,10 @@ void main() {
           tester.getCenter(find.text('Mon Jan 1 ')).dx - tester.getCenter(find.text('AM')).dx;
 
       await tester.pumpWidget(
-        SizedBox(
+        CupertinoApp(
+          home: SizedBox(
             height: 400.0,
             width: 800.0,
-          child: Directionality(
-            textDirection: TextDirection.ltr,
             child: CupertinoDatePicker(
               mode: CupertinoDatePickerMode.dateAndTime,
               onDateTimeChanged: (_) {},
@@ -377,11 +369,10 @@ void main() {
 
     testWidgets('width of picker in date mode is consistent', (WidgetTester tester) async {
       await tester.pumpWidget(
-        SizedBox(
+        CupertinoApp(
+          home: SizedBox(
             height: 400.0,
             width: 400.0,
-          child: Directionality(
-            textDirection: TextDirection.ltr,
             child: CupertinoDatePicker(
               mode: CupertinoDatePickerMode.date,
               onDateTimeChanged: (_) {},
@@ -396,11 +387,10 @@ void main() {
           tester.getCenter(find.text('January')).dx - tester.getCenter(find.text('2018')).dx;
 
       await tester.pumpWidget(
-        SizedBox(
+        CupertinoApp(
+          home: SizedBox(
             height: 400.0,
             width: 800.0,
-          child: Directionality(
-            textDirection: TextDirection.ltr,
             child: CupertinoDatePicker(
               mode: CupertinoDatePickerMode.date,
               onDateTimeChanged: (_) {},
@@ -419,11 +409,10 @@ void main() {
 
     testWidgets('width of picker in time mode is consistent', (WidgetTester tester) async {
       await tester.pumpWidget(
-        SizedBox(
+        CupertinoApp(
+          home: SizedBox(
             height: 400.0,
             width: 400.0,
-          child: Directionality(
-            textDirection: TextDirection.ltr,
             child: CupertinoDatePicker(
               mode: CupertinoDatePickerMode.time,
               onDateTimeChanged: (_) {},
@@ -438,11 +427,10 @@ void main() {
           tester.getCenter(find.text('10')).dx - tester.getCenter(find.text('AM')).dx;
 
       await tester.pumpWidget(
-        SizedBox(
+        CupertinoApp(
+          home: SizedBox(
             height: 400.0,
             width: 800.0,
-          child: Directionality(
-            textDirection: TextDirection.ltr,
             child: CupertinoDatePicker(
               mode: CupertinoDatePickerMode.time,
               onDateTimeChanged: (_) {},
@@ -462,11 +450,10 @@ void main() {
     testWidgets('picker automatically scrolls away from invalid date on month change', (WidgetTester tester) async {
       DateTime date;
       await tester.pumpWidget(
-        SizedBox(
+        CupertinoApp(
+          home: SizedBox(
             height: 400.0,
             width: 400.0,
-          child: Directionality(
-            textDirection: TextDirection.ltr,
             child: CupertinoDatePicker(
               mode: CupertinoDatePickerMode.date,
               onDateTimeChanged: (DateTime newDate) {
@@ -501,11 +488,10 @@ void main() {
     testWidgets('picker automatically scrolls away from invalid date on day change', (WidgetTester tester) async {
       DateTime date;
       await tester.pumpWidget(
-        SizedBox(
+        CupertinoApp(
+          home: SizedBox(
             height: 400.0,
             width: 400.0,
-          child: Directionality(
-            textDirection: TextDirection.ltr,
             child: CupertinoDatePicker(
               mode: CupertinoDatePickerMode.date,
               onDateTimeChanged: (DateTime newDate) {
@@ -555,11 +541,10 @@ void main() {
     testWidgets('picker automatically scrolls the am/pm column when the hour column changes enough', (WidgetTester tester) async {
       DateTime date;
       await tester.pumpWidget(
-        SizedBox(
+        CupertinoApp(
+          home: SizedBox(
             height: 400.0,
             width: 400.0,
-          child: Directionality(
-            textDirection: TextDirection.ltr,
             child: CupertinoDatePicker(
               mode: CupertinoDatePickerMode.time,
               onDateTimeChanged: (DateTime newDate) {

packages/flutter/test/material/app_test.dart

@@ -3,6 +3,7 @@
 // found in the LICENSE file.
 
 import 'package:flutter_test/flutter_test.dart';
+import 'package:flutter/cupertino.dart';
 import 'package:flutter/material.dart';
 
 class StateMarker extends StatefulWidget {
@@ -412,4 +413,26 @@ void main() {
     ));
     expect(key.currentState, isInstanceOf<NavigatorState>());
   });
+
+  testWidgets('Has default material and cupertino localizations', (WidgetTester tester) async {
+    await tester.pumpWidget(
+      MaterialApp(
+        home: Builder(
+          builder: (BuildContext context) {
+            return Column(
+              children: <Widget>[
+                Text(MaterialLocalizations.of(context).selectAllButtonLabel),
+                Text(CupertinoLocalizations.of(context).selectAllButtonLabel),
+              ],
+            );
+          },
+        ),
+      ),
+    );
+
+    // Default US "select all" text.
+    expect(find.text('SELECT ALL'), findsOneWidget);
+    // Default Cupertino US "select all" text.
+    expect(find.text('Select All'), findsOneWidget);
+  });
 }