Flutter23.flipper

ex:

import 'dart:math';

import 'package:flutter/material.dart';

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

class HomePage extends StatefulWidget {
  @override
  _HomePageState createState() => _HomePageState();
}

class _HomePageState extends State
    with SingleTickerProviderStateMixin {
  Animation _animation;
  AnimationController _animationController;
  bool reversed = false;

  @override
  void initState() {
    super.initState();
    _animationController =
        AnimationController(vsync: this, duration: Duration(seconds: 1));//持续时间
    _animation = TweenSequence([
      TweenSequenceItem(
        tween: Tween(begin: 0.0, end: -pi / 2),//从正常位置到反转
        weight: 0.5,
      ),
      TweenSequenceItem(
        tween: Tween(begin: pi / 2, end: 0.0),//从反转到正常位置
        weight: 0.5,
      ),
    ]).animate(_animationController);
  }

  @override
  void dispose() {
    super.dispose();
    _animationController.dispose();
  }

  //是否反转
  _doAnim() {
    reversed ? _animationController.reverse() : _animationController.forward();
    reversed = !reversed;
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Center(
        child: AnimatedBuilder(
            animation: _animation,
            builder: (BuildContext context, Widget child) {
              return Transform(
                transform: Matrix4.identity()//生成矩阵
                  ..setEntry(3, 2, 0.001)//3d效果
                  ..rotateY(_animation.value),//从左到右翻转
                alignment: Alignment.center,//居中
                child: GestureDetector(
                  onTap: _doAnim,
                  child: IndexedStack(
                    children: [
                      CardOne(),
                      CardTwo(),
                    ],
                    alignment: Alignment.center,
                    index: _animationController.value < 0.5 ? 0 : 1,//0~1 //小于0.5显示第0个页面，否则显示第一个
                  ),
                ),
              );
            }),
      ),
    );
  }
}

class CardOne extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Card(
      color: Color(0xffff0000),
      child: Container(
        width: 200.0,
        height: 200.0,
        child: Text(
          'This is red',
          style: TextStyle(color: Color(0xffffffff), fontSize: 30.0),
        ),
      ),
    );
  }
}

class CardTwo extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return Card(
      color: Color(0xff0000ff),
      child: Container(
        width: 200.0,
        height: 200.0,
        child: Text(
          'this is blue',
          style: TextStyle(color: Color(0xffffffff), fontSize: 30.0),
        ),
      ),
    );
  }
}

输出：