Question

我正在尝试为两个方形容器设置动画，以便在点击它们时对其进行动画缩放。我在线上看到了所有这些显示了小部件动画的转换类示例，但是当我使用转换类时，比例仅从其初始值跳到其最终值。

我的最终目标是为容器创建动画，使其在每次被点击时“反弹”，就像您在Web开发中对bounce.js所做的那样。要了解我的意思，您可以转到http://bouncejs.com，单击左上角的“选择预设”，从下拉菜单中选择果冻，然后单击“播放动画”。

这可以通过transform类完成吗？

这是我的代码：

import 'package:flutter/material.dart';

void main() => runApp(MyApp());

class MyApp extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: MyHomePage(),
    );
  }
}

class MyHomePage extends StatefulWidget {
  _MyHomePageState createState() => _MyHomePageState();
}

var squareScaleA = 0.5;
var squareScaleB = 0.5;

class _MyHomePageState extends State<MyHomePage> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text("Bounce Example"),
      ),
      body: Stack(
        children: <Widget>[
          Container(
            width: 300.0,
            height: 150.0,
            color: Colors.yellowAccent,
          ),
          Column(
            children: <Widget>[
              Row(
                children: <Widget>[
                  GestureDetector(
                    onTap: () {
                      setState(() {
                        squareScaleA = 1.0;
                      });
                    },
                    child: Transform.scale(
                      scale: squareScaleA,
                      child: Container(
                        width: 150.0,
                        height: 150.0,
                        color: Colors.green,
                      ),
                    ),
                  ),
                  GestureDetector(
                    onTap: () {
                      setState(() {
                        squareScaleB = 1.0;
                      });
                    },
                    child: Transform.scale(
                      scale: squareScaleB,
                      child: Container(
                        width: 150.0,
                        height: 150.0,
                        color: Colors.blue,
                      ),
                    ),
                  ),
                ],
              ),
            ],
          ),
        ],
      ),
    );
  }
}

在此先感谢您的帮助！

Answer 1

您需要使用Animations，可以开始使用AnimationController，这非常简单，我已修复示例：

    class _MyHomePageState extends State<TestingNewWidget>
        with TickerProviderStateMixin {
      var squareScaleA = 0.5;
      var squareScaleB = 0.5;
      AnimationController _controllerA;
      AnimationController _controllerB;

      @override
      void initState() {
        _controllerA = AnimationController(
            vsync: this,
            lowerBound: 0.5,
            upperBound: 1.0,
            duration: Duration(seconds: 1));
        _controllerA.addListener(() {
          setState(() {
            squareScaleA = _controllerA.value;
          });
        });
        _controllerB = AnimationController(
            vsync: this,
            lowerBound: 0.5,
            upperBound: 1.0,
            duration: Duration(seconds: 1));
        _controllerB.addListener(() {
          setState(() {
            squareScaleB = _controllerB.value;
          });
        });
        super.initState();
      }

      @override
      void dispose() {
        _controllerA.dispose();
        _controllerB.dispose();
        super.dispose();
      }

      @override
      Widget build(BuildContext context) {
        return Scaffold(
          appBar: AppBar(
            title: Text("Bounce Example"),
          ),
          body: Stack(
            children: <Widget>[
              Container(
                width: 300.0,
                height: 150.0,
                color: Colors.yellowAccent,
              ),
              Column(
                children: <Widget>[
                  Row(
                    children: <Widget>[
                      GestureDetector(
                        onTap: () {
                          if (_controllerA.isCompleted) {
                            _controllerA.reverse();
                          } else {
                            _controllerA.forward(from: 0.0);
                          }
                        },
                        child: Transform.scale(
                          scale: squareScaleA,
                          child: Container(
                            width: 150.0,
                            height: 150.0,
                            color: Colors.green,
                          ),
                        ),
                      ),
                      GestureDetector(
                        onTap: () {
                          if (_controllerB.isCompleted) {
                            _controllerB.reverse();
                          } else {
                            _controllerB.forward(from: 0.0);
                          }
                        },
                        child: Transform.scale(
                          scale: squareScaleB,
                          child: Container(
                            width: 150.0,
                            height: 150.0,
                            color: Colors.blue,
                          ),
                        ),
                      ),
                    ],
                  ),
                ],
              ),
            ],
          ),
        );
      }
    }

您还可以在此处了解有关动画的更多信息：https://flutter.dev/docs/development/ui/animations

可以使用Flutter的transform类为比例动画吗？

1 个答案: