Flutter实现重复弹性动画

Question

为了实现这个动画

我在下面写了这段代码，但是弹性动画在项目上不起​​作用，我不确定是什么问题，

我想重复这个动画

import 'package:flutter/material.dart';

void main()=>runApp(MaterialApp(home: Avatar(),));

class Avatar extends StatefulWidget {
  @override
  State<StatefulWidget> createState()=>_Avatar();
}

class _Avatar extends State<Avatar> with TickerProviderStateMixin{
  AnimationController avatarController;
  Animation<double> avatarSize;

  @override
  void initState() {
    super.initState();

    avatarController= AnimationController(
      duration: const Duration(seconds: 1),
      vsync: this,
    );

    avatarSize = new Tween(begin: 0.0, end: 1.0).animate(
      new CurvedAnimation(
        parent: avatarController,
        curve: new Interval(
          0.100,
          0.400,
          curve: Curves.elasticOut,
        ),
      ),
    );

    avatarController.repeate();
  }
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Stack(
        fit:StackFit.expand,
        children: <Widget>[
          AnimatedBuilder(
            animation: avatarController,
            builder: (context, widget) => Align(
              child: Container(
                width: 50.0,
                height: 50.0,
                color:Colors.green
              ),
            ),
          )
        ],
      ),
    );
  }
}

Answer 1

输出:

---

您可以使用 duration 和 Tween 来细化它。

void main() => runApp(MaterialApp(home: Avatar()));

class Avatar extends StatefulWidget {
  @override
  State<StatefulWidget> createState() => _Avatar();
}

class _Avatar extends State<Avatar> with TickerProviderStateMixin {
  AnimationController _controller;
  Tween<double> _tween = Tween(begin: 0.75, end: 2);

  @override
  void initState() {
    super.initState();

    _controller = AnimationController(duration: const Duration(milliseconds: 700), vsync: this);
    _controller.repeat(reverse: true);
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Stack(
        children: <Widget>[
          Align(
            child: ScaleTransition(
              scale: _tween.animate(CurvedAnimation(parent: _controller, curve: Curves.elasticOut)),
              child: SizedBox(
                height: 100,
                width: 100,
                child: CircleAvatar(backgroundImage: AssetImage(chocolateImage)),
              ),
            ),
          ),
        ],
      ),
    );
  }
}