Adding onEnd callback to implicit animated widgets (#38979)

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

@@ -227,10 +227,11 @@ class AnimatedTheme extends ImplicitlyAnimatedWidget {
     this.isMaterialAppTheme = false,
     Curve curve = Curves.linear,
     Duration duration = kThemeAnimationDuration,
+    VoidCallback onEnd,
     @required this.child,
   }) : assert(child != null),
        assert(data != null),
-       super(key: key, curve: curve, duration: duration);
+       super(key: key, curve: curve, duration: duration, onEnd: onEnd);
 
   /// Specifies the color and typography values for descendant widgets.
   final ThemeData data;

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

@@ -276,6 +276,7 @@ abstract class ImplicitlyAnimatedWidget extends StatefulWidget {
     Key key,
     this.curve = Curves.linear,
     @required this.duration,
+    this.onEnd,
   }) : assert(curve != null),
        assert(duration != null),
        super(key: key);
@@ -286,6 +287,12 @@ abstract class ImplicitlyAnimatedWidget extends StatefulWidget {
   /// The duration over which to animate the parameters of this container.
   final Duration duration;
 
+  /// Called every time an animation completes.
+  ///
+  /// This can be useful to trigger additional actions (e.g. another animation)
+  /// at the end of the current animation.
+  final VoidCallback onEnd;
+
   @override
   ImplicitlyAnimatedWidgetState<ImplicitlyAnimatedWidget> createState();
 
@@ -356,6 +363,17 @@ abstract class ImplicitlyAnimatedWidgetState<T extends ImplicitlyAnimatedWidget>
       debugLabel: kDebugMode ? '${widget.toStringShort()}' : null,
       vsync: this,
     );
+    _controller.addStatusListener((AnimationStatus status) {
+      switch (status) {
+        case AnimationStatus.completed:
+          if (widget.onEnd != null)
+            widget.onEnd();
+          break;
+        case AnimationStatus.dismissed:
+        case AnimationStatus.forward:
+        case AnimationStatus.reverse:
+      }
+    });
     _updateCurve();
     _constructTweens();
     didUpdateTweens();
@@ -624,6 +642,7 @@ class AnimatedContainer extends ImplicitlyAnimatedWidget {
     this.child,
     Curve curve = Curves.linear,
     @required Duration duration,
+    VoidCallback onEnd,
   }) : assert(margin == null || margin.isNonNegative),
        assert(padding == null || padding.isNonNegative),
        assert(decoration == null || decoration.debugAssertIsValid()),
@@ -638,7 +657,7 @@ class AnimatedContainer extends ImplicitlyAnimatedWidget {
           ? constraints?.tighten(width: width, height: height)
             ?? BoxConstraints.tightFor(width: width, height: height)
           : constraints,
-       super(key: key, curve: curve, duration: duration);
+       super(key: key, curve: curve, duration: duration, onEnd: onEnd);
 
   /// The [child] contained by the container.
   ///
@@ -780,9 +799,10 @@ class AnimatedPadding extends ImplicitlyAnimatedWidget {
     this.child,
     Curve curve = Curves.linear,
     @required Duration duration,
+    VoidCallback onEnd,
   }) : assert(padding != null),
        assert(padding.isNonNegative),
-       super(key: key, curve: curve, duration: duration);
+       super(key: key, curve: curve, duration: duration, onEnd: onEnd);
 
   /// The amount of space by which to inset the child.
   final EdgeInsetsGeometry padding;
@@ -859,8 +879,9 @@ class AnimatedAlign extends ImplicitlyAnimatedWidget {
     this.child,
     Curve curve = Curves.linear,
     @required Duration duration,
+    VoidCallback onEnd,
   }) : assert(alignment != null),
-       super(key: key, curve: curve, duration: duration);
+       super(key: key, curve: curve, duration: duration, onEnd: onEnd);
 
   /// How to align the child.
   ///
@@ -967,9 +988,10 @@ class AnimatedPositioned extends ImplicitlyAnimatedWidget {
     this.height,
     Curve curve = Curves.linear,
     @required Duration duration,
+    VoidCallback onEnd,
   }) : assert(left == null || right == null || width == null),
        assert(top == null || bottom == null || height == null),
-       super(key: key, curve: curve, duration: duration);
+       super(key: key, curve: curve, duration: duration, onEnd: onEnd);
 
   /// Creates a widget that animates the rectangle it occupies implicitly.
   ///
@@ -980,13 +1002,14 @@ class AnimatedPositioned extends ImplicitlyAnimatedWidget {
     Rect rect,
     Curve curve = Curves.linear,
     @required Duration duration,
+    VoidCallback onEnd,
   }) : left = rect.left,
        top = rect.top,
        width = rect.width,
        height = rect.height,
        right = null,
        bottom = null,
-       super(key: key, curve: curve, duration: duration);
+       super(key: key, curve: curve, duration: duration, onEnd: onEnd);
 
   /// The widget below this widget in the tree.
   ///
@@ -1118,9 +1141,10 @@ class AnimatedPositionedDirectional extends ImplicitlyAnimatedWidget {
     this.height,
     Curve curve = Curves.linear,
     @required Duration duration,
+    VoidCallback onEnd,
   }) : assert(start == null || end == null || width == null),
        assert(top == null || bottom == null || height == null),
-       super(key: key, curve: curve, duration: duration);
+       super(key: key, curve: curve, duration: duration, onEnd: onEnd);
 
   /// The widget below this widget in the tree.
   ///
@@ -1274,9 +1298,10 @@ class AnimatedOpacity extends ImplicitlyAnimatedWidget {
     @required this.opacity,
     Curve curve = Curves.linear,
     @required Duration duration,
+    VoidCallback onEnd,
     this.alwaysIncludeSemantics = false,
   }) : assert(opacity != null && opacity >= 0.0 && opacity <= 1.0),
-       super(key: key, curve: curve, duration: duration);
+       super(key: key, curve: curve, duration: duration, onEnd: onEnd);
 
   /// The widget below this widget in the tree.
   ///
@@ -1369,12 +1394,13 @@ class AnimatedDefaultTextStyle extends ImplicitlyAnimatedWidget {
     this.maxLines,
     Curve curve = Curves.linear,
     @required Duration duration,
+    VoidCallback onEnd,
   }) : assert(style != null),
        assert(child != null),
        assert(softWrap != null),
        assert(overflow != null),
        assert(maxLines == null || maxLines > 0),
-       super(key: key, curve: curve, duration: duration);
+       super(key: key, curve: curve, duration: duration, onEnd: onEnd);
 
   /// The widget below this widget in the tree.
   ///
@@ -1484,6 +1510,7 @@ class AnimatedPhysicalModel extends ImplicitlyAnimatedWidget {
     this.animateShadowColor = true,
     Curve curve = Curves.linear,
     @required Duration duration,
+    VoidCallback onEnd,
   }) : assert(child != null),
        assert(shape != null),
        assert(clipBehavior != null),
@@ -1493,7 +1520,7 @@ class AnimatedPhysicalModel extends ImplicitlyAnimatedWidget {
        assert(shadowColor != null),
        assert(animateColor != null),
        assert(animateShadowColor != null),
-       super(key: key, curve: curve, duration: duration);
+       super(key: key, curve: curve, duration: duration, onEnd: onEnd);
 
   /// The widget below this widget in the tree.
   ///

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

@@ -127,12 +127,12 @@ class TweenAnimationBuilder<T> extends ImplicitlyAnimatedWidget {
     @required Duration duration,
     Curve curve = Curves.linear,
     @required this.builder,
-    this.onEnd,
+    VoidCallback onEnd,
     this.child,
   }) : assert(tween != null),
        assert(curve != null),
        assert(builder != null),
-       super(key: key, duration: duration, curve: curve);
+       super(key: key, duration: duration, curve: curve, onEnd: onEnd);
 
   /// Defines the target value for the animation.
   ///
@@ -186,12 +186,6 @@ class TweenAnimationBuilder<T> extends ImplicitlyAnimatedWidget {
   /// performance significantly in some cases and is therefore a good practice.
   final Widget child;
 
-  /// Called every time an animation completes.
-  ///
-  /// This can be useful to trigger additional actions (e.g. another animation)
-  /// at the end of the current animation.
-  final VoidCallback onEnd;
-
   @override
   ImplicitlyAnimatedWidgetState<ImplicitlyAnimatedWidget> createState() {
     return _TweenAnimationBuilderState<T>();
@@ -206,27 +200,11 @@ class _TweenAnimationBuilderState<T> extends AnimatedWidgetBaseState<TweenAnimat
     _currentTween = widget.tween;
     _currentTween.begin ??= _currentTween.end;
     super.initState();
-    // The statusListener is removed when the superclass disposes the controller.
-    controller.addStatusListener(_onAnimationStatusChanged);
     if (_currentTween.begin != _currentTween.end) {
       controller.forward();
     }
   }
 
-  void _onAnimationStatusChanged(AnimationStatus status) {
-    switch (status) {
-      case AnimationStatus.dismissed:
-      case AnimationStatus.forward:
-      case AnimationStatus.reverse:
-        break;
-      case AnimationStatus.completed:
-        if (widget.onEnd != null) {
-          widget.onEnd();
-        }
-        break;
-    }
-  }
-
   @override
   void forEachTween(TweenVisitor<dynamic> visitor) {
     assert(

packages/flutter/test/widgets/implicit_animations_test.dart

@@ -2,10 +2,29 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+import 'package:flutter/material.dart';
 import 'package:flutter_test/flutter_test.dart';
 import 'package:flutter/widgets.dart';
 
+class MockOnEndFunction implements Function {
+  int called = 0;
+
+  void call() {
+    called++;
+  }
+}
+
+const Duration animationDuration = Duration(milliseconds:1000);
+const Duration additionalDelay = Duration(milliseconds:1);
+
 void main() {
+  MockOnEndFunction mockOnEndFunction;
+  const Key switchKey = Key('switchKey');
+
+  setUp(() {
+    mockOnEndFunction = MockOnEndFunction();
+  });
+
   testWidgets('BoxConstraintsTween control test', (WidgetTester tester) async {
     final BoxConstraintsTween tween = BoxConstraintsTween(
       begin: BoxConstraints.tight(const Size(20.0, 50.0)),
@@ -47,4 +66,355 @@ void main() {
     final Matrix4 result = tween.lerp(0.25);
     expect(result, equals(Matrix4.translationValues(11.0, 21.0, 31.0)));
   });
+
+  testWidgets('AnimatedContainer onEnd callback test', (WidgetTester tester) async {
+    await tester.pumpWidget(wrap(
+        child: TestAnimatedWidget(callback: mockOnEndFunction, switchKey: switchKey, state: _TestAnimatedContainerWidgetState(),)
+    ));
+
+    final Finder widgetFinder = find.byKey(switchKey);
+
+    await tester.tap(widgetFinder);
+
+    await tester.pump();
+    expect(mockOnEndFunction.called, 0);
+    await tester.pump(animationDuration);
+    expect(mockOnEndFunction.called, 0);
+    await tester.pump(additionalDelay);
+    expect(mockOnEndFunction.called, 1);
+  });
+
+  testWidgets('AnimatedPadding onEnd callback test', (WidgetTester tester) async {
+    await tester.pumpWidget(wrap(
+        child: TestAnimatedWidget(callback: mockOnEndFunction, switchKey: switchKey, state: _TestAnimatedPaddingWidgetState(),)
+    ));
+
+    final Finder widgetFinder = find.byKey(switchKey);
+
+    await tester.tap(widgetFinder);
+
+    await tester.pump();
+    expect(mockOnEndFunction.called, 0);
+    await tester.pump(animationDuration);
+    expect(mockOnEndFunction.called, 0);
+    await tester.pump(additionalDelay);
+    expect(mockOnEndFunction.called, 1);
+  });
+
+  testWidgets('AnimatedAlign onEnd callback test', (WidgetTester tester) async {
+    await tester.pumpWidget(wrap(
+        child: TestAnimatedWidget(callback: mockOnEndFunction, switchKey: switchKey, state: _TestAnimatedAlignWidgetState(),)
+    ));
+
+    final Finder widgetFinder = find.byKey(switchKey);
+
+    await tester.tap(widgetFinder);
+
+    await tester.pump();
+    expect(mockOnEndFunction.called, 0);
+    await tester.pump(animationDuration);
+    expect(mockOnEndFunction.called, 0);
+    await tester.pump(additionalDelay);
+    expect(mockOnEndFunction.called, 1);
+  });
+
+  testWidgets('AnimatedPositioned onEnd callback test', (WidgetTester tester) async {
+    await tester.pumpWidget(wrap(
+        child: TestAnimatedWidget(callback: mockOnEndFunction, switchKey: switchKey, state: _TestAnimatedPositionedWidgetState(),)
+    ));
+
+    final Finder widgetFinder = find.byKey(switchKey);
+
+    await tester.tap(widgetFinder);
+
+    await tester.pump();
+    expect(mockOnEndFunction.called, 0);
+    await tester.pump(animationDuration);
+    expect(mockOnEndFunction.called, 0);
+    await tester.pump(additionalDelay);
+    expect(mockOnEndFunction.called, 1);
+  });
+
+  testWidgets('AnimatedPositionedDirectional onEnd callback test', (WidgetTester tester) async {
+    await tester.pumpWidget(wrap(
+        child: TestAnimatedWidget(callback: mockOnEndFunction, switchKey: switchKey, state: _TestAnimatedPositionedDirectionalWidgetState(),)
+    ));
+
+    final Finder widgetFinder = find.byKey(switchKey);
+
+    await tester.tap(widgetFinder);
+
+    await tester.pump();
+    expect(mockOnEndFunction.called, 0);
+    await tester.pump(animationDuration);
+    expect(mockOnEndFunction.called, 0);
+    await tester.pump(additionalDelay);
+    expect(mockOnEndFunction.called, 1);
+  });
+
+  testWidgets('AnimatedOpacity onEnd callback test', (WidgetTester tester) async {
+    await tester.pumpWidget(wrap(
+        child: TestAnimatedWidget(callback: mockOnEndFunction, switchKey: switchKey, state: _TestAnimatedOpacityWidgetState(),)
+    ));
+
+    final Finder widgetFinder = find.byKey(switchKey);
+
+    await tester.tap(widgetFinder);
+
+    await tester.pump();
+    expect(mockOnEndFunction.called, 0);
+    await tester.pump(animationDuration);
+    expect(mockOnEndFunction.called, 0);
+    await tester.pump(additionalDelay);
+    expect(mockOnEndFunction.called, 1);
+  });
+
+  testWidgets('AnimatedDefaultTextStyle onEnd callback test', (WidgetTester tester) async {
+    await tester.pumpWidget(wrap(
+        child: TestAnimatedWidget(callback: mockOnEndFunction, switchKey: switchKey, state: _TestAnimatedDefaultTextStyleWidgetState(),)
+    ));
+
+    final Finder widgetFinder = find.byKey(switchKey);
+
+    await tester.tap(widgetFinder);
+
+    await tester.pump();
+    expect(mockOnEndFunction.called, 0);
+    await tester.pump(animationDuration);
+    expect(mockOnEndFunction.called, 0);
+    await tester.pump(additionalDelay);
+    expect(mockOnEndFunction.called, 1);
+  });
+
+  testWidgets('AnimatedPhysicalModel onEnd callback test', (WidgetTester tester) async {
+    await tester.pumpWidget(wrap(
+        child: TestAnimatedWidget(callback: mockOnEndFunction, switchKey: switchKey, state: _TestAnimatedPhysicalModelWidgetState(),)
+    ));
+
+    final Finder widgetFinder = find.byKey(switchKey);
+
+    await tester.tap(widgetFinder);
+
+    await tester.pump();
+    expect(mockOnEndFunction.called, 0);
+    await tester.pump(animationDuration);
+    expect(mockOnEndFunction.called, 0);
+    await tester.pump(additionalDelay);
+    expect(mockOnEndFunction.called, 1);
+  });
+
+  testWidgets('TweenAnimationBuilder onEnd callback test', (WidgetTester tester) async {
+    await tester.pumpWidget(wrap(
+        child: TestAnimatedWidget(callback: mockOnEndFunction, switchKey: switchKey, state: _TestTweenAnimationBuilderWidgetState(),)
+    ));
+
+    final Finder widgetFinder = find.byKey(switchKey);
+
+    await tester.tap(widgetFinder);
+
+    await tester.pump();
+    expect(mockOnEndFunction.called, 0);
+    await tester.pump(animationDuration);
+    expect(mockOnEndFunction.called, 0);
+    await tester.pump(additionalDelay);
+    expect(mockOnEndFunction.called, 1);
+  });
+
+  testWidgets('AnimatedTheme onEnd callback test', (WidgetTester tester) async {
+    await tester.pumpWidget(wrap(
+        child: TestAnimatedWidget(callback: mockOnEndFunction, switchKey: switchKey, state: _TestAnimatedThemeWidgetState(),)
+    ));
+
+    final Finder widgetFinder = find.byKey(switchKey);
+
+    await tester.tap(widgetFinder);
+
+    await tester.pump();
+    expect(mockOnEndFunction.called, 0);
+    await tester.pump(animationDuration);
+    expect(mockOnEndFunction.called, 0);
+    await tester.pump(additionalDelay);
+    expect(mockOnEndFunction.called, 1);
+  });
+}
+
+Widget wrap({Widget child}) {
+  return Directionality(
+    textDirection: TextDirection.ltr,
+    child: Material(
+      child: Center(child: child),
+    ),
+  );
+}
+
+class TestAnimatedWidget extends StatefulWidget {
+  const TestAnimatedWidget({this.callback, this.switchKey, this.state});
+  @required
+  final VoidCallback callback;
+  @required
+  final Key switchKey;
+  @required
+  final State<StatefulWidget> state;
+
+  @override
+  State<StatefulWidget> createState() => state;
+}
+
+abstract class _TestAnimatedWidgetState extends State<TestAnimatedWidget> {
+  bool toggle = false;
+  final Widget child = const Placeholder();
+  final Duration duration = animationDuration;
+
+  void onChanged(bool v) {
+    setState(() {
+      toggle = v;
+    });
+  }
+
+  Widget getAnimatedWidget();
+
+  @override
+  Widget build(BuildContext context) {
+    final Widget animatedWidget = getAnimatedWidget();
+
+    return Stack(
+      children: <Widget>[
+        animatedWidget,
+        Switch(key: widget.switchKey, value: toggle, onChanged: onChanged),
+      ],
+    );
+  }
+}
+
+
+class _TestAnimatedContainerWidgetState extends _TestAnimatedWidgetState {
+  @override
+  Widget getAnimatedWidget() {
+    return AnimatedContainer(
+      child: child,
+      duration: duration,
+      onEnd: widget.callback,
+      width: toggle ? 10 : 20,
+    );
+  }
+}
+
+class _TestAnimatedPaddingWidgetState extends _TestAnimatedWidgetState {
+  @override
+  Widget getAnimatedWidget() {
+    return AnimatedPadding(
+      child: child,
+      duration: duration,
+      onEnd: widget.callback,
+      padding:
+      toggle ? const EdgeInsets.all(8.0) : const EdgeInsets.all(16.0),
+    );
+  }
+}
+
+class _TestAnimatedAlignWidgetState extends _TestAnimatedWidgetState {
+  @override
+  Widget getAnimatedWidget() {
+    return AnimatedAlign(
+      child: child,
+      duration: duration,
+      onEnd: widget.callback,
+      alignment: toggle ? Alignment.topLeft : Alignment.bottomRight,
+    );
+  }
+}
+
+class _TestAnimatedPositionedWidgetState extends _TestAnimatedWidgetState {
+  @override
+  Widget getAnimatedWidget() {
+    return AnimatedPositioned(
+      child: child,
+      duration: duration,
+      onEnd: widget.callback,
+      left: toggle ? 10 : 20,
+    );
+  }
+}
+
+class _TestAnimatedPositionedDirectionalWidgetState extends _TestAnimatedWidgetState {
+  @override
+  Widget getAnimatedWidget() {
+    return AnimatedPositionedDirectional(
+      child: child,
+      duration: duration,
+      onEnd: widget.callback,
+      start: toggle ? 10 : 20,
+    );
+  }
+}
+
+class _TestAnimatedOpacityWidgetState extends _TestAnimatedWidgetState {
+  @override
+  Widget getAnimatedWidget() {
+    return AnimatedOpacity(
+      child: child,
+      duration: duration,
+      onEnd: widget.callback,
+      opacity: toggle ? 0.1 : 0.9,
+    );
+  }
+}
+
+class _TestAnimatedDefaultTextStyleWidgetState extends _TestAnimatedWidgetState {
+  @override
+  Widget getAnimatedWidget() {
+    return AnimatedDefaultTextStyle(
+        child: child,
+        duration: duration,
+        onEnd: widget.callback,
+        style: toggle
+            ? const TextStyle(fontStyle: FontStyle.italic)
+            : const TextStyle(fontStyle: FontStyle.normal));
+  }
+}
+
+class _TestAnimatedPhysicalModelWidgetState extends _TestAnimatedWidgetState {
+  @override
+  Widget getAnimatedWidget() {
+    return AnimatedPhysicalModel(
+      child: child,
+      duration: duration,
+      onEnd: widget.callback,
+      color: toggle ? Colors.red : Colors.green,
+      elevation: 0,
+      shadowColor: Colors.blue,
+      shape: BoxShape.rectangle,
+    );
+  }
+}
+
+class _TestTweenAnimationBuilderWidgetState extends _TestAnimatedWidgetState {
+  @override
+  Widget getAnimatedWidget() {
+    return TweenAnimationBuilder<double>(
+        child: child,
+        tween: Tween<double>(begin: 1, end: 2),
+        duration: duration,
+        onEnd: widget.callback,
+        builder: (BuildContext context, double size, Widget child) {
+          return Container(
+            child: child,
+            width: size,
+            height: size,
+          );
+        }
+    );
+  }
+}
+
+class _TestAnimatedThemeWidgetState extends _TestAnimatedWidgetState {
+  @override
+  Widget getAnimatedWidget() {
+    return AnimatedTheme(
+      child: child,
+      data: toggle ? ThemeData.dark() : ThemeData.light(),
+      duration: duration,
+      onEnd: widget.callback,
+    );
+  }
 }