Added CurvedAnimation Sample (#385)

animations/README.md

@@ -12,7 +12,7 @@ Sample apps that showcasing Flutter's animation features
 
 Building blocks and patterns
 
-1. **AnimatedContainerDemo** Demonstrates how to use `AnimatedContainer`
+1. **AnimatedContainerDemo** Demonstrates how to use `AnimatedContainer`.
 2. **PageRouteBuilderDemo** Demonstrates how to use `Tween` and `Animation` to
 *build a custom page route transition.
 3. **AnimationControllerDemo** Demonstrates how to use an `AnimationController`.
@@ -23,7 +23,9 @@ Building blocks and patterns
 6. **CustomTweenDemo** Demonstrates how to extend `Tween`.
 7. **TweenSequenceDemo** Demonstrates how to use `TweenSequence` to build a
 button that changes between different colors.
-8. **FadeTransitionDemo** Demonstrates how to use `FadeTransition`. 
+8. **FadeTransitionDemo** Demonstrates how to use `FadeTransition`.
+9. **AnimatedPositionedDemo** Demonstrates how to use `AnimatedPositioned`.
+10. **AnimatedSwitcherDemo** Demonstrates how to use `AnimatedSwitcher`. 
 
 ### Misc
 
@@ -39,8 +41,9 @@ it using a `PageRouteBuilder`.
 spring simulation.
 - **CardSwipeDemo** A swipeable card that demonstrates how to use gesture
 detection to drive an animation.
-- **AnimatedList** Demonstrates how to use `AnimatedList`
+- **AnimatedList** Demonstrates how to use `AnimatedList`.
 - **HeroAnimationDemo** Demonstrates how to use `Hero` animation.
+- **CurvedAnimationDemo** Demonstrates how to use different curves in `CurvedAnimation`.
 
 ## Other Resources
 

animations/lib/main.dart

@@ -16,6 +16,7 @@ import 'src/basics/10_animated_switcher.dart';
 import 'src/misc/animated_list.dart';
 import 'src/misc/card_swipe.dart';
 import 'src/misc/carousel.dart';
+import 'src/misc/curved_animation.dart';
 import 'src/misc/expand_card.dart';
 import 'src/misc/focus_image.dart';
 import 'src/misc/hero_animation.dart';
@@ -108,6 +109,10 @@ final miscDemos = [
       name: 'Hero Animation',
       route: HeroAnimationDemo.routeName,
       builder: (context) => HeroAnimationDemo()),
+  Demo(
+      name: 'Curved Animation',
+      route: CurvedAnimationDemo.routeName,
+      builder: (context) => CurvedAnimationDemo()),
 ];
 
 final basicDemoRoutes =

animations/lib/src/misc/curved_animation.dart

@@ -0,0 +1,165 @@
+// Copyright 2020 The Flutter team. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+import 'dart:math' as math;
+import 'package:flutter/material.dart';
+
+class CurvedAnimationDemo extends StatefulWidget {
+  static const String routeName = '/misc/curved_animation';
+
+  @override
+  _CurvedAnimationDemoState createState() => _CurvedAnimationDemoState();
+}
+
+class CurveChoice {
+  final Curve curve;
+  final String name;
+  const CurveChoice({this.curve, this.name});
+}
+
+class _CurvedAnimationDemoState extends State<CurvedAnimationDemo>
+    with SingleTickerProviderStateMixin {
+  AnimationController controller;
+  Animation<double> animationRotation;
+  Animation<Offset> animationTranslation;
+  static const _duration = Duration(seconds: 4);
+  List<CurveChoice> curves = [
+    CurveChoice(curve: Curves.bounceIn, name: 'Bounce In'),
+    CurveChoice(curve: Curves.bounceOut, name: 'Bounce Out'),
+    CurveChoice(curve: Curves.easeInCubic, name: 'Ease In Cubic'),
+    CurveChoice(curve: Curves.easeOutCubic, name: 'Ease Out Cubic'),
+    CurveChoice(curve: Curves.easeInExpo, name: 'Ease In Expo'),
+    CurveChoice(curve: Curves.easeOutExpo, name: 'Ease Out Expo'),
+    CurveChoice(curve: Curves.elasticIn, name: 'Elastic In'),
+    CurveChoice(curve: Curves.elasticOut, name: 'Elastic Out'),
+    CurveChoice(curve: Curves.easeInQuart, name: 'Ease In Quart'),
+    CurveChoice(curve: Curves.easeOutQuart, name: 'Ease Out Quart'),
+    CurveChoice(curve: Curves.easeInCirc, name: 'Ease In Circle'),
+    CurveChoice(curve: Curves.easeOutCirc, name: 'Ease Out Circle'),
+  ];
+  CurveChoice selectedForwardCurve, selectedReverseCurve;
+  CurvedAnimation curvedAnimation;
+
+  @override
+  void initState() {
+    super.initState();
+    controller = AnimationController(
+      duration: _duration,
+      vsync: this,
+    );
+    selectedForwardCurve = curves[0];
+    selectedReverseCurve = curves[0];
+    curvedAnimation = CurvedAnimation(
+      parent: controller,
+      curve: selectedForwardCurve.curve,
+      reverseCurve: selectedReverseCurve.curve,
+    );
+    animationRotation = Tween<double>(
+      begin: 0,
+      end: 2 * math.pi,
+    ).animate(curvedAnimation)
+      ..addListener(() {
+        setState(() {});
+      })
+      ..addStatusListener((status) {
+        if (status == AnimationStatus.completed) {
+          controller.reverse();
+        }
+      });
+    animationTranslation = Tween<Offset>(
+      begin: Offset(-1, 0),
+      end: Offset(1, 0),
+    ).animate(curvedAnimation)
+      ..addListener(() {
+        setState(() {});
+      })
+      ..addStatusListener((status) {
+        if (status == AnimationStatus.completed) {
+          controller.reverse();
+        }
+      });
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    return Scaffold(
+      appBar: AppBar(
+        title: Text('Curved Animation'),
+      ),
+      body: Column(
+        children: [
+          SizedBox(height: 20.0),
+          Text(
+            'Select Curve for forward motion',
+            style: Theme.of(context).textTheme.title,
+          ),
+          DropdownButton<CurveChoice>(
+            items: curves.map((curve) {
+              return DropdownMenuItem<CurveChoice>(
+                  value: curve, child: Text(curve.name));
+            }).toList(),
+            onChanged: (newCurve) {
+              setState(() {
+                selectedForwardCurve = newCurve;
+                curvedAnimation.curve = selectedForwardCurve.curve;
+              });
+            },
+            value: selectedForwardCurve,
+          ),
+          SizedBox(height: 15.0),
+          Text(
+            'Select Curve for reverse motion',
+            style: Theme.of(context).textTheme.title,
+          ),
+          DropdownButton<CurveChoice>(
+            items: curves.map((curve) {
+              return DropdownMenuItem<CurveChoice>(
+                  value: curve, child: Text(curve.name));
+            }).toList(),
+            onChanged: (newCurve) {
+              setState(() {
+                selectedReverseCurve = newCurve;
+                curvedAnimation.reverseCurve = selectedReverseCurve.curve;
+              });
+            },
+            value: selectedReverseCurve,
+          ),
+          SizedBox(height: 35.0),
+          Transform.rotate(
+            angle: animationRotation.value,
+            child: Center(
+              child: Container(
+                child: FlutterLogo(
+                  size: 100,
+                ),
+              ),
+            ),
+          ),
+          SizedBox(height: 35.0),
+          FractionalTranslation(
+            translation: animationTranslation.value,
+            child: Container(
+              child: FlutterLogo(
+                size: 100,
+              ),
+            ),
+          ),
+          SizedBox(height: 25.0),
+          RaisedButton(
+            onPressed: () {
+              controller.forward();
+            },
+            child: Text('Animate'),
+          ),
+        ],
+      ),
+    );
+  }
+
+  @override
+  void dispose() {
+    controller.dispose();
+    super.dispose();
+  }
+}