Flutter 动画（显式动画、隐式动画、Hero动画、页面转场动画、交错动画）

前言

当前案例 Flutter SDK版本：3.13.2

显式动画

Tween({this.begin,this.end}) 两个构造参数，分别是 开始值 和 结束值，根据这两个值，提供了控制动画的方法，以下是常用的；

• controller.forward() : 向前，执行 begin 到 end 的动画，执行结束后，处于end状态；
• controller.reverse() : 反向，当动画已经完成，进行还原动画；
• controller.reset() : 重置，当动画已经完成，进行还原，注意这个是直接还原 ，没有动画；

使用方式一

使用 addListener() 和 setState()；

import 'package:flutter/material.dart';

class TweenAnimation extends StatefulWidget {
  const TweenAnimation({super.key});

  @override
  State<TweenAnimation> createState() => _TweenAnimationState();
}

/// 使用 addListener() 和 setState()
class _TweenAnimationState extends State<TweenAnimation>
    with SingleTickerProviderStateMixin {
  late Animation<double> animation;
  late AnimationController controller;

  @override
  void initState() {
    super.initState();
    controller = AnimationController(
        duration: const Duration(milliseconds: 2000), vsync: this);
    animation = Tween<double>(begin: 50, end: 100).animate(controller)
      ..addListener(() {
        setState(() {}); // 更新UI
      })..addStatusListener((status) {
        debugPrint('status：$status'); // 监听动画执行状态
      });
  }

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

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
          title: const Text(
        '显式动画',
        style: TextStyle(fontSize: 20),
      )),
      body: SizedBox(
        width: MediaQuery.of(context).size.width,
        height: MediaQuery.of(context).size.height,
        child: Column(
          mainAxisAlignment: MainAxisAlignment.spaceAround,
          children: [
            Row(
              mainAxisAlignment: MainAxisAlignment.center,
              children: [
                SizedBox(
                  width: animation.value,
                  height: animation.value,
                  child: const FlutterLogo(),
                ),
                ElevatedButton(
                  onPressed: () {
                    if (controller.isCompleted) {
                      controller.reverse();
                    } else {
                      controller.forward();
                    }
                    // controller.forward(); // 向前，执行 begin 到 end 的动画，执行结束后，处于end状态
                    // controller.reverse(); // 反向，当动画已经完成，进行还原动画
                    // controller.reset(); // 重置，当动画已经完成，进行还原，注意这个是直接还原，没有动画
                  },
                  child: const Text('缩放'),
                )
              ],
            )
          ],
        ),
      ),
    );
  }
}

使用方式二

AnimatedWidget ，解决痛点：不需要再使用 addListener() 和 setState()；

import 'package:flutter/material.dart';

class TweenAnimation extends StatefulWidget {
  const TweenAnimation({super.key});

  @override
  State<TweenAnimation> createState() => _TweenAnimationState();
}

/// 测试 AnimatedWidget
class _TweenAnimationState extends State<TweenAnimation>
    with SingleTickerProviderStateMixin {
  late Animation<double> animation;
  late AnimationController controller;

  @override
  void initState() {
    super.initState();
    controller = AnimationController(duration: const Duration(milliseconds: 2000), vsync: this);
    animation = Tween<double>(begin: 50, end: 100).animate(controller)
      ..addStatusListener((status) {
        debugPrint('status：$status'); // 监听动画执行状态
      });
  }

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

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
          title: const Text(
        '显式动画',
        style: TextStyle(fontSize: 20),
      )),
      body: SizedBox(
        width: MediaQuery.of(context).size.width,
        height: MediaQuery.of(context).size.height,
        child: Column(
          mainAxisAlignment: MainAxisAlignment.spaceAround,
          children: [
            Row(
              mainAxisAlignment: MainAxisAlignment.center,
              children: [
                AnimatedLogo(animation: animation),
                ElevatedButton(
                  onPressed: () {
                    if (controller.isCompleted) {
                      controller.reverse();
                    } else {
                      controller.forward();
                    }
                    // controller.forward(); // 向前，执行 begin 到 end 的动画，执行结束后，处于end状态
                    // controller.reverse(); // 反向，当动画已经完成，进行还原动画
                    // controller.reset(); // 重置，当动画已经完成，进行还原，注意这个是直接还原，没有动画
                  },
                  child: const Text('缩放'),
                )
              ],
            )
          ],
        ),
      ),
    );
  }
}

/// 使用 AnimatedWidget，创建显式动画
/// 解决痛点：不需要再使用 addListener() 和 setState()
class AnimatedLogo extends AnimatedWidget {
  const AnimatedLogo({super.key, required Animation<double> animation})
      : super(listenable: animation);

  @override
  Widget build(BuildContext context) {
    final animation = listenable as Animation<double>;
    return Center(
      child: Container(
        margin: const EdgeInsets.symmetric(vertical: 10),
        width: animation.value,
        height: animation.value,
        child: const FlutterLogo(),
      ),
    );
  }
}

使用方式三

使用 内置的显式动画 widget；

后缀是 Transition 的组件，几乎都是 显式动画 widget；

import 'package:flutter/material.dart';

class TweenAnimation extends StatefulWidget {
  const TweenAnimation({super.key});

  @override
  State<TweenAnimation> createState() => _TweenAnimationState();
}

/// 使用 内置的显式动画Widget
class _TweenAnimationState extends State<TweenAnimation>
    with SingleTickerProviderStateMixin {
  late Animation<double> animation;
  late AnimationController controller;

  @override
  void initState() {
    super.initState();
    controller = AnimationController(
        duration: const Duration(milliseconds: 1000), vsync: this);
    animation = Tween<double>(begin: 0.1, end: 1.0).animate(controller)
      ..addListener(() {
        setState(() {}); // 更新UI
      })
      ..addStatusListener((status) {
        debugPrint('status：$status'); // 监听动画执行状态
      });
  }

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

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
          title: const Text(
        '显式动画',
        style: TextStyle(fontSize: 20),
      )),
      body: SizedBox(
        width: MediaQuery.of(context).size.width,
        height: MediaQuery.of(context).size.height,
        child: Column(
          mainAxisAlignment: MainAxisAlignment.spaceAround,
          children: [
            Row(
              mainAxisAlignment: MainAxisAlignment.center,
              children: [
                /// 单个显示动画
                FadeTransition(
                  opacity: animation,
                  child: const SizedBox(
                    width: 100,
                    height: 100,
                    child: FlutterLogo(),
                  ),
                ),

                /// 多个显示动画 配合使用
                // FadeTransition( // 淡入淡出
                //   opacity: animation,
                //   child: RotationTransition( // 旋转
                //     turns: animation,
                //     child: ScaleTransition( // 更替
                //       scale: animation,
                //       child: const SizedBox(
                //         width: 100,
                //         height: 100,
                //         child: FlutterLogo(),
                //       ),
                //     ),
                //   ),
                // ),
                ElevatedButton(
                  onPressed: () {
                    if (controller.isCompleted) {
                      controller.reverse();
                    } else {
                      controller.forward();
                    }
                    // controller.forward(); // 向前，执行 begin 到 end 的动画，执行结束后，处于end状态
                    // controller.reverse(); // 反向，当动画已经完成，进行还原动画
                    // controller.reset(); // 重置，当动画已经完成，进行还原，注意这个是直接还原，没有动画
                  },
                  child: const Text('淡入淡出'),
                )
              ],
            )
          ],
        ),
      ),
    );
  }
}

使用方式四

AnimatedBuilder ，这种方式感觉是 通过逻辑 动态选择 Widget，比如 flag ? widgetA : widgetB；

官方解释：

• AnimatedBuilder 知道如何渲染过渡效果
• 但 AnimatedBuilder 不会渲染 widget，也不会控制动画对象。
• 使用 AnimatedBuilder 描述一个动画是其他 widget 构建方法的一部分。
• 如果只是单纯需要用可重复使用的动画定义一个 widget，可参考文档：简单使用 AnimatedWidget。

import 'package:flutter/material.dart';

class TweenAnimation extends StatefulWidget {
  const TweenAnimation({super.key});

  @override
  State<TweenAnimation> createState() => _TweenAnimationState();
}

/// 测试 AnimatedBuilder
class _TweenAnimationState extends State<TweenAnimation>
    with SingleTickerProviderStateMixin {
  late Animation<double> animation;
  late AnimationController controller;

  @override
  void initState() {
    super.initState();
    controller = AnimationController(
        duration: const Duration(milliseconds: 2000), vsync: this);
    animation = Tween<double>(begin: 50, end: 100).animate(controller)
      ..addStatusListener((status) {
        debugPrint('status：$status'); // 监听动画执行状态
      });
  }

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

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
          title: const Text(
            '显式动画',
            style: TextStyle(fontSize: 20),
          )),
      body: SizedBox(
        width: MediaQuery.of(context).size.width,
        height: MediaQuery.of(context).size.height,
        child: Column(
          mainAxisAlignment: MainAxisAlignment.spaceAround,
          children: [
            Row(
              mainAxisAlignment: MainAxisAlignment.center,
              children: [
                GrowTransition(
                    animation: animation,
                    child: const FlutterLogo()),
                ElevatedButton(
                  onPressed: () {
                    if (controller.isCompleted) {
                      controller.reverse();
                    } else {
                      controller.forward();
                    }
                    // controller.forward(); // 向前，执行 begin 到 end 的动画，执行结束后，处于end状态
                    // controller.reverse(); // 反向，当动画已经完成，进行还原动画
                    // controller.reset(); // 重置，当动画已经完成，进行还原，注意这个是直接还原，没有动画
                  },
                  child: const Text('缩放'),
                )
              ],
            )
          ],
        ),
      ),
    );
  }
}

class GrowTransition extends StatelessWidget {
  final Widget child;
  final Animation<double> animation;

  const GrowTransition(
      {required this.child, required this.animation, super.key});

  @override
  Widget build(BuildContext context) {
    return Center(
      child: AnimatedBuilder(
        animation: animation,
        builder: (context, child) {
          return SizedBox(
            width: animation.value,
            height: animation.value,
            child: child,
          );
        },
        child: child,
      ),
    );
  }
}

使用方式五

CurvedAnimation 曲线动画，一个Widget，同时使用多个动画；

import 'package:flutter/material.dart';

class TweenAnimation extends StatefulWidget {
  const TweenAnimation({super.key});

  @override
  State<TweenAnimation> createState() => _TweenAnimationState();
}

/// 测试 动画同步使用
class _TweenAnimationState extends State<TweenAnimation>
    with SingleTickerProviderStateMixin {
  late Animation<double> animation;
  late AnimationController controller;

  @override
  void initState() {
    super.initState();
    controller = AnimationController(duration: const Duration(milliseconds: 2000), vsync: this);
    animation = CurvedAnimation(parent: controller, curve: Curves.easeIn)
      ..addStatusListener((status) {
        debugPrint('status：$status'); // 监听动画执行状态
      });
  }

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

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
          title: const Text(
        '显式动画',
        style: TextStyle(fontSize: 20),
      )),
      body: SizedBox(
        width: MediaQuery.of(context).size.width,
        height: MediaQuery.of(context).size.height,
        child: Column(
          mainAxisAlignment: MainAxisAlignment.spaceAround,
          children: [
            Row(
              mainAxisAlignment: MainAxisAlignment.center,
              children: [
                AnimatedLogoSync(animation: animation),
                ElevatedButton(
                  onPressed: () {
                    if (controller.isCompleted) {
                      controller.reverse();
                    } else {
                      controller.forward();
                    }
                    // controller.forward(); // 向前，执行 begin 到 end 的动画，执行结束后，处于end状态
                    // controller.reverse(); // 反向，当动画已经完成，进行还原动画
                    // controller.reset(); // 重置，当动画已经完成，进行还原，注意这个是直接还原，没有动画
                  },
                  child: const Text('缩放 + 淡入淡出'),
                )
              ],
            )
          ],
        ),
      ),
    );
  }
}

/// 动画同步使用
class AnimatedLogoSync extends AnimatedWidget {
  AnimatedLogoSync({super.key, required Animation<double> animation})
      : super(listenable: animation);

  final Tween<double> _opacityTween = Tween<double>(begin: 0.1, end: 1);
  final Tween<double> _sizeTween = Tween<double>(begin: 50, end: 100);

  @override
  Widget build(BuildContext context) {
    final animation = listenable as Animation<double>;
    return Center(
      child: Opacity(
        opacity: _opacityTween.evaluate(animation),
        child: SizedBox(
          width: _sizeTween.evaluate(animation),
          height: _sizeTween.evaluate(animation),
          child: const FlutterLogo(),
        ),
      ),
    );
  }
}

隐式动画

• 根据属性值变化 ，为 UI 中的 widget 添加动作并创造视觉效果 ，有些库包含各种各样可以帮你管理动画的widget，这些widgets被统称为 隐式动画 或 隐式动画 widget。
• 前缀是 Animated 的组件，几乎都是 隐式动画 widget；

import 'dart:math';

import 'package:flutter/material.dart';

class ImplicitAnimation extends StatefulWidget {
  const ImplicitAnimation({super.key});

  @override
  State<ImplicitAnimation> createState() => _ImplicitAnimationState();
}

class _ImplicitAnimationState extends State<ImplicitAnimation> {

  double opacity = 0;

  late Color color;
  late double borderRadius;
  late double margin;

  double randomBorderRadius() {
    return Random().nextDouble() * 64;
  }

  double randomMargin() {
    return Random().nextDouble() * 32;
  }

  Color randomColor() {
    return Color(0xFFFFFFFF & Random().nextInt(0xFFFFFFFF));
  }

  @override
  void initState() {
    super.initState();
    color = randomColor();
    borderRadius = randomBorderRadius();
    margin = randomMargin();
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
          title: const Text(
        '隐式动画',
        style: TextStyle(fontSize: 20),
      )),
      body: SizedBox(
        width: MediaQuery.of(context).size.width,
        height: MediaQuery.of(context).size.height,
        child: Column(
          mainAxisAlignment: MainAxisAlignment.spaceAround,
          children: [
            Row(
              mainAxisAlignment: MainAxisAlignment.center,
              children: [
                AnimatedOpacity(
                  opacity: opacity,
                  curve: Curves.easeInOutBack,
                  duration: const Duration(milliseconds: 1000),
                  child: Container(
                    width: 50,
                    height: 50,
                    margin: const EdgeInsets.only(right: 12),
                    color: Colors.primaries[2],
                  ),
                ),
                ElevatedButton(
                  onPressed: () {
                    if(opacity == 0) {
                      opacity = 1;
                    } else {
                      opacity = 0;
                    }
                    setState(() {});
                  },
                  child: const Text('淡入或淡出'),
                )
              ],
            ),
            Row(
              mainAxisAlignment: MainAxisAlignment.center,
              children: [
                AnimatedContainer(
                  width: 50,
                  height: 50,
                  margin: EdgeInsets.all(margin),
                  decoration: BoxDecoration(
                    color: color,
                    borderRadius: BorderRadius.circular(borderRadius)
                  ),
                  curve: Curves.easeInBack,
                  duration: const Duration(milliseconds: 1000),
                ),
                ElevatedButton(
                  onPressed: () {
                    color = randomColor();
                    borderRadius = randomBorderRadius();
                    margin = randomMargin();
                    setState(() {});
                  },
                  child: const Text('形状变化'),
                )
              ],
            )
          ],
        ),
      ),
    );
  }

}

显示和隐式的区别

看图，隐式动画 就是 显示动画 封装后的产物，是不是很蒙，这有什么意义？

应用场景不同：如果想 控制动画 ，使用 显示动画 ，controller.forward()、controller.reverse()、controller.reset()，反之只是在Widget属性值发生改变，进行UI过渡 这种简单操作，使用 隐式动画；

误区

Flutter显式动画的关键对象 Tween，翻译过来 补间 ，联想到 Android原生的补间动画 ，就会有一个问题，Android原生的补间动画，只是视觉上 的UI变化，对象属性并非 真正改变，那么Flutter是否也是如此？

答案：非也，是真的改变了 ，和Android原生补间动画不同，看图：

以下偏移动画，在Flutter中的，点击偏移后 的矩形位置，可以触发提示 ，反之Android原生不可以，只能在矩形原来的位置，才能触发；

Flutte 提示库 以及 封装相关 的代码

fluttertoast: ^8.2.4

toast_util.dart

import 'package:flutter/material.dart';
import 'package:fluttertoast/fluttertoast.dart';

class ToastUtil {
  static FToast fToast = FToast();

  static void init(BuildContext context) {
    fToast.init(context);
  }

  static void showToast(String msg) {
    Widget toast = Row(
      mainAxisAlignment: MainAxisAlignment.center,
      children: [
        Container(
          padding: const EdgeInsets.symmetric(horizontal: 24.0, vertical: 12.0),
          decoration: BoxDecoration(
            borderRadius: BorderRadius.circular(25.0),
            color: Colors.greenAccent,
          ),
          alignment: Alignment.center,
          child: Text(msg),
        )
      ],
    );

    fToast.showToast(
      child: toast,
      gravity: ToastGravity.BOTTOM,
      toastDuration: const Duration(seconds: 2),
    );
  }
}

Flutter显示动画 代码

import 'package:flutter/material.dart';
import 'package:flutter_animation/util/toast_util.dart';

class TweenAnimation extends StatefulWidget {
  const TweenAnimation({super.key});

  @override
  State<TweenAnimation> createState() => _TweenAnimationState();
}

/// 测试显式动画，属性是否真的改变了
class _TweenAnimationState extends State<TweenAnimation>
    with SingleTickerProviderStateMixin {
  late Animation<Offset> animation;
  late AnimationController controller;

  @override
  void initState() {
    super.initState();
    controller = AnimationController(
        duration: const Duration(milliseconds: 500), vsync: this);
    animation =
        Tween<Offset>(begin: const Offset(0, 0), end: const Offset(1.5, 0))
            .animate(controller)
          ..addStatusListener((status) {
            debugPrint('status：$status'); // 监听动画执行状态
          });
  }

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

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
          title: const Text(
        'Flutter 显式动画',
        style: TextStyle(fontSize: 20),
      )),
      body: Container(
        width: MediaQuery.of(context).size.width,
        height: MediaQuery.of(context).size.height,
        color: Colors.primaries[5],
        child: Stack(
          children: [
            Align(
              alignment: Alignment.center,
              child: Container(
                width: 80,
                height: 80,
                decoration: BoxDecoration(
                  border: Border.all(color: Colors.white, width: 1.0),
                ),
              ),
            ),
            Align(
              alignment: Alignment.center,
              child: SlideTransition(
                position: animation,
                child: InkWell(
                  onTap: () {
                    ToastUtil.showToast('点击了');
                  },
                  child: Container(
                    width: 80,
                    height: 80,
                    color: Colors.primaries[2],
                  ),
                ),
              ),
            ),
            Positioned(
              left: (MediaQuery.of(context).size.width / 2) - 35,
              top: 200,
              child: ElevatedButton(
                onPressed: () {
                  if (controller.isCompleted) {
                    controller.reverse();
                  } else {
                    controller.forward();
                  }
                  // controller.forward(); // 向前，执行 begin 到 end 的动画，执行结束后，处于end状态
                  // controller.reverse(); // 反向，当动画已经完成，进行还原动画
                  // controller.reset(); // 重置，当动画已经完成，进行还原，注意这个是直接还原，没有动画
                },
                child: const Text('偏移'),
              ),
            )
          ],
        ),
      ),
    );
  }
}

Flutter隐式动画 代码

import 'package:flutter/material.dart';
import 'package:flutter_animation/util/toast_util.dart';

class ImplicitAnimation extends StatefulWidget {
  const ImplicitAnimation({super.key});

  @override
  State<ImplicitAnimation> createState() => _ImplicitAnimationState();
}

/// 测试隐式动画，属性是否真的改变了
class _ImplicitAnimationState extends State<ImplicitAnimation> {
  late double offsetX = 0;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
          title: const Text(
        'Flutter 隐式动画',
        style: TextStyle(fontSize: 20),
      )),
      body: Container(
        width: MediaQuery.of(context).size.width,
        height: MediaQuery.of(context).size.height,
        color: Colors.primaries[5],
        child: Stack(
          children: [
            Align(
              alignment: Alignment.center,
              child: Container(
                width: 80,
                height: 80,
                decoration: BoxDecoration(
                  border: Border.all(color: Colors.white, width: 1.0),
                ),
              ),
            ),
            Align(
              alignment: Alignment.center,
              child: AnimatedSlide(
                offset: Offset(offsetX, 0),
                duration: const Duration(milliseconds: 500),
                child: InkWell(
                  onTap: () {
                    ToastUtil.showToast('点击了');
                  },
                  child: Container(
                    width: 80,
                    height: 80,
                    color: Colors.primaries[2],
                  ),
                ),
              ),
            ),
            Positioned(
              left: (MediaQuery.of(context).size.width / 2) - 35,
              top: 200,
              child: ElevatedButton(
                onPressed: () {
                  if (offsetX == 0) {
                    offsetX = 1.5;
                  } else {
                    offsetX = 0;
                  }
                  setState(() {});
                },
                child: const Text('偏移'),
              ),
            )
          ],
        ),
      ),
    );
  }
}

Android原生补间动画 代码

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical">

    <TextView
        android:layout_width="match_parent"
        android:layout_height="50dp"
        android:background="@android:color/holo_blue_light"
        android:gravity="center|left"
        android:text="Android原生 补间动画"
        android:paddingStart="16dp"
        android:textColor="@android:color/white"
        android:textSize="20sp" />

    <TextView
        android:id="@+id/border"
        android:layout_width="50dp"
        android:layout_height="50dp"
        android:layout_gravity="center"
        android:layout_marginBottom="50dp"
        android:background="@drawable/border" />

    <TextView
        android:id="@+id/offset_box"
        android:layout_width="50dp"
        android:layout_height="50dp"
        android:layout_gravity="center"
        android:layout_marginBottom="50dp"
        android:background="@android:color/holo_orange_light" />

    <Button
        android:id="@+id/offset_x"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center"
        android:layout_marginTop="12dp"
        android:text="偏移" />

</FrameLayout>

import android.app.Activity
import android.os.Bundle
import android.view.View
import android.view.animation.TranslateAnimation
import android.widget.Toast
import com.example.flutter_animation.databinding.ActivityMainBinding

class MainActivity : Activity(), View.OnClickListener {

    private lateinit var bind: ActivityMainBinding

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        bind = ActivityMainBinding.inflate(layoutInflater)
        setContentView(bind.root)
        bind.offsetX.setOnClickListener(this)
        bind.offsetBox.setOnClickListener(this)
    }

    private fun offsetAnimation() {
        val translateAnimation = TranslateAnimation(0f, 200f, 0f, 0f)
        translateAnimation.duration = 800
        translateAnimation.fillAfter = true
        bind.offsetBox.startAnimation(translateAnimation)
    }

    override fun onClick(v: View?) {
        if (bind.offsetX == v) {
            offsetAnimation()
        } else if (bind.offsetBox == v) {
            Toast.makeText(this,"点击了",Toast.LENGTH_SHORT).show()
        }
    }

}

Hero动画

应用于 元素共享 的动画。

下面这三个图片详情案例的使用方式，将 Widget 从 A页面 共享到 B页面 后，改变Widget大小，被称为 标准 hero 动画；

图片详情案例一：本地图片

import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';

import 'package:flutter/scheduler.dart' show timeDilation;

class HeroAnimation extends StatefulWidget {
  const HeroAnimation({super.key});

  @override
  State<HeroAnimation> createState() => _HeroAnimationState();
}

/// 将 Widget 从 A页面 共享到 B页面 后，改变Widget大小
class _HeroAnimationState extends State<HeroAnimation> {
  /// 测试本地图片
  final List<String> images = [
    'assets/images/01.jpg',
    'assets/images/02.jpg',
    'assets/images/03.jpg',
    'assets/images/04.jpg',
  ];

  @override
  Widget build(BuildContext context) {
    // 减慢动画速度，可以通过此值帮助开发,
    // 注意这个值是针对所有动画，所以路由动画也会受影响
    // timeDilation = 10.0;

    return Scaffold(
      appBar: AppBar(
        title: const Text('Photo List Page'),
      ),
      body: Container(
        width: MediaQuery.of(context).size.width,
        height: MediaQuery.of(context).size.height,
        alignment: Alignment.topLeft,
        child: GridView.count(
          padding: const EdgeInsets.all(10),
          crossAxisCount: 2,
          mainAxisSpacing: 10,
          crossAxisSpacing: 10,
          children: List.generate(
              images.length,
              (index) => PhotoHero(
                    photo: images[index],
                    size: 100,
                    onTap: () {
                      Navigator.of(context).push(CupertinoPageRoute<void>(
                        builder: (context) => PhotoDetail(
                            size: MediaQuery.of(context).size.width,
                            photo: images[index]),
                      ));
                    },
                  )),
        ),
      ),
    );
  }
}

class PhotoHero extends StatelessWidget {
  const PhotoHero({
    super.key,
    required this.photo,
    this.onTap,
    required this.size,
  });

  final String photo;
  final VoidCallback? onTap;
  final double size;

  @override
  Widget build(BuildContext context) {
    return SizedBox(
      width: size,
      height: size,
      child: Hero(
        tag: photo,
        child: Material(
          color: Colors.transparent,
          child: InkWell(
            onTap: onTap,
            /// 测试本地图片
            child: Image.asset(
                          photo,
                          fit: BoxFit.cover,
                        ),
          ),
        ),
      ),
    );
  }
}

class PhotoDetail extends StatelessWidget {
  const PhotoDetail({
    super.key,
    required this.photo,
    required this.size,
  });

  final String photo;
  final double size;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Photo Detail Page'),
      ),
      body: Column(
        children: [
          Container(
            color: Colors.lightBlueAccent,
            padding: const EdgeInsets.all(16),
            alignment: Alignment.topCenter,
            child: PhotoHero(
              photo: photo,
              size: size,
              onTap: () {
                Navigator.of(context).pop();
              },
            ),
          ),
          const Text(
            '详情xxx',
            style: TextStyle(fontSize: 20),
          )
        ],
      ),
    );
  }
}

图片详情案例二：网络图片

可以看出，在有延迟的情况下，效果没有本地图片好；

import 'package:flutter/cupertino.dart';
import 'package:flutter/material.dart';

import 'package:flutter/scheduler.dart' show timeDilation;

class HeroAnimation extends StatefulWidget {
  const HeroAnimation({super.key});

  @override
  State<HeroAnimation> createState() => _HeroAnimationState();
}

/// 将 Widget 从 A页面 共享到 B页面 后，改变Widget大小
class _HeroAnimationState extends State<HeroAnimation> {

  /// 测试网络图片
  final List<String> images = [
    'https://img1.baidu.com/it/u=1161835547,3275770506&fm=253&fmt=auto&app=138&f=JPEG?w=800&h=500',
    'https://p9.toutiaoimg.com/origin/pgc-image/6d817289d3b44d53bb6e55aa81e41bd2?from=pc',
    'https://img0.baidu.com/it/u=102503057,4196586556&fm=253&fmt=auto&app=138&f=BMP?w=500&h=724',
    'https://lmg.jj20.com/up/allimg/1114/041421115008/210414115008-3-1200.jpg',
  ];

  @override
  Widget build(BuildContext context) {
    // 减慢动画速度，可以通过此值帮助开发,
    // 注意这个值是针对所有动画，所以路由动画也会受影响
    // timeDilation = 10.0;

    return Scaffold(
      appBar: AppBar(
        title: const Text('Photo List Page'),
      ),
      body: Container(
        width: MediaQuery.of(context).size.width,
        height: MediaQuery.of(context).size.height,
        alignment: Alignment.topLeft,
        child: GridView.count(
          padding: const EdgeInsets.all(10),
          crossAxisCount: 2,
          mainAxisSpacing: 10,
          crossAxisSpacing: 10,
          children: List.generate(
              images.length,
              (index) => PhotoHero(
                    photo: images[index],
                    size: 100,
                    onTap: () {
                      Navigator.of(context).push(CupertinoPageRoute<void>(
                        builder: (context) => PhotoDetail(
                            size: MediaQuery.of(context).size.width,
                            photo: images[index]),
                      ));
                    },
                  )),
        ),
      ),
    );
  }
}

class PhotoHero extends StatelessWidget {
  const PhotoHero({
    super.key,
    required this.photo,
    this.onTap,
    required this.size,
  });

  final String photo;
  final VoidCallback? onTap;
  final double size;

  @override
  Widget build(BuildContext context) {
    return SizedBox(
      width: size,
      height: size,
      child: Hero(
        tag: photo,
        child: Material(
          color: Colors.transparent,
          child: InkWell(
            onTap: onTap,
            /// 测试网络图片
            child: Image.network(
              photo,
              fit: BoxFit.cover,
            ),
          ),
        ),
      ),
    );
  }
}

class PhotoDetail extends StatelessWidget {
  const PhotoDetail({
    super.key,
    required this.photo,
    required this.size,
  });

  final String photo;
  final double size;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: const Text('Photo Detail Page'),
      ),
      body: Column(
        children: [
          Container(
            color: Colors.lightBlueAccent,
            padding: const EdgeInsets.all(16),
            alignment: Alignment.topCenter,
            child: PhotoHero(
              photo: photo,
              size: size,
              onTap: () {
                Navigator.of(context).pop();
              },
            ),
          ),
          const Text(
            '详情xxx',
            style: TextStyle(fontSize: 20),
          )
        ],
      ),
    );
  }
}

图片详情案例三：背景透明

import 'package:flutter/material.dart';

import 'package:flutter/scheduler.dart' show timeDilation;

class HeroAnimation extends StatefulWidget {
  const HeroAnimation({super.key});

  @override
  State<HeroAnimation> createState() => _HeroAnimationState();
}

/// 测试 新页面背景透明色 的图片详情
class _HeroAnimationState extends State<HeroAnimation> {
  /// 测试本地图片
  final List<String> images = [
    'assets/images/01.jpg',
    'assets/images/02.jpg',
    'assets/images/03.jpg',
    'assets/images/04.jpg',
  ];

  @override
  Widget build(BuildContext context) {
    // 减慢动画速度，可以通过此值帮助开发,
    // 注意这个值是针对所有动画，所以路由动画也会受影响
    // timeDilation = 10.0;

    return Scaffold(
      appBar: AppBar(
        title: const Text('Photo List Page'),
      ),
      body: Container(
        width: MediaQuery.of(context).size.width,
        height: MediaQuery.of(context).size.height,
        alignment: Alignment.topLeft,
        child: GridView.count(
          padding: const EdgeInsets.all(10),
          crossAxisCount: 2,
          mainAxisSpacing: 10,
          crossAxisSpacing: 10,
          children: List.generate(
              images.length,
                  (index) => PhotoHero(
                photo: images[index],
                size: 100,
                onTap: () {
                  Navigator.of(context).push(
                    PageRouteBuilder<void>(
                      opaque: false, // 新页面，背景色不透明度
                      pageBuilder: (context, animation, secondaryAnimation) {
                        return PhotoDetail(
                            size: MediaQuery.of(context).size.width,
                            photo: images[index]);
                      },
                    ),
                  );
                },
              )),
        ),
      ),
    );
  }
}

class PhotoHero extends StatelessWidget {
  const PhotoHero({
    super.key,
    required this.photo,
    this.onTap,
    required this.size,
  });

  final String photo;
  final VoidCallback? onTap;
  final double size;

  @override
  Widget build(BuildContext context) {
    return SizedBox(
      width: size,
      height: size,
      child: Hero(
        tag: photo,
        child: Material(
          color: Colors.transparent,
          child: InkWell(
            onTap: onTap,
            /// 测试本地图片
            child: Image.asset(
              photo,
              fit: BoxFit.cover,
            ),
          ),
        ),
      ),
    );
  }
}

class PhotoDetail extends StatelessWidget {
  const PhotoDetail({
    super.key,
    required this.photo,
    required this.size,
  });

  final String photo;
  final double size;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: Colors.transparent,
      // backgroundColor: const Color(0x66000000),
      body: Column(
        mainAxisAlignment: MainAxisAlignment.center,
        children: [
          Container(
            padding: const EdgeInsets.all(16),
            alignment: Alignment.center,
            child: PhotoHero(
              photo: photo,
              size: size,
              onTap: () {
                Navigator.of(context).pop();
              },
            ),
          ),
          const Text(
            '详情xxx',
            style: TextStyle(fontSize: 20,color: Colors.white),
          )
        ],
      ),
    );
  }
}

图片形状转换案例：圆形 转 矩形

这个案例的使用方式，被称为 径向hero动画；

• 径向hero动画的 径 是半径距离，圆形状 向 矩形状转换，矩形状的对角半径距离 = 圆形状半径距离 * 2；
• 这个是官方模版代码，我也没改什么;
• 官方代码地址：github.com/cfug/flutte...
• 问题：这种官方代码是 初始化为 圆形 点击向 矩形改变 的方式，我尝试反向操作：初始化为 矩形 点击向 圆形改变 ，但没有成功，如果有哪位同学找到实现方式，麻烦评论区留言；

我是这样修改的：

class RadialExpansion extends StatelessWidget {
  ... ... 

  @override
  Widget build(BuildContext context) {
    /// 原来的代码
    // 控制形状变化的核心代码
    // return ClipOval( // 圆形
    //   child: Center(
    //     child: SizedBox(
    //       width: clipRectSize,
    //       height: clipRectSize,
    //       child: ClipRect( // 矩形
    //         child: child,
    //       ),
    //     ),
    //   ),
    // );

    /// 尝试修改 形状顺序
    return ClipRect( // 矩形
      child: Center(
        child: SizedBox(
          width: clipRectSize,
          height: clipRectSize,
          child: ClipOval( // 圆形
            child: child,
          ),
        ),
      ),
    );

  }
}

官方代码演示

import 'package:flutter/material.dart';
import 'dart:math' as math;

import 'package:flutter/scheduler.dart' show timeDilation;

class HeroAnimation extends StatefulWidget {
  const HeroAnimation({super.key});

  @override
  State<HeroAnimation> createState() => _HeroAnimationState();
}

/// 将 Widget 从 A页面 共享到 B页面 后，改变Widget形状
class _HeroAnimationState extends State<HeroAnimation> {

  static double kMinRadius = 32.0;
  static double kMaxRadius = 128.0;
  static Interval opacityCurve =
  const Interval(0.0, 0.75, curve: Curves.fastOutSlowIn);

  static RectTween _createRectTween(Rect? begin, Rect? end) {
    return MaterialRectCenterArcTween(begin: begin, end: end);
  }

  static Widget _buildPage(
      BuildContext context, String imageName, String description) {
    return Container(
      color: Theme.of(context).canvasColor,
      child: Center(
        child: Card(
          elevation: 8,
          child: Column(
            mainAxisSize: MainAxisSize.min,
            children: [
              SizedBox(
                width: kMaxRadius * 2.0,
                height: kMaxRadius * 2.0,
                child: Hero(
                  createRectTween: _createRectTween,
                  tag: imageName,
                  child: RadialExpansion(
                    maxRadius: kMaxRadius,
                    child: Photo(
                      photo: imageName,
                      onTap: () {
                        Navigator.of(context).pop();
                      },
                    ),
                  ),
                ),
              ),
              Text(
                description,
                style: const TextStyle(fontWeight: FontWeight.bold),
                textScaleFactor: 3,
              ),
              const SizedBox(height: 16),
            ],
          ),
        ),
      ),
    );
  }

  Widget _buildHero(
      BuildContext context,
      String imageName,
      String description,
      ) {
    return SizedBox(
      width: kMinRadius * 2.0,
      height: kMinRadius * 2.0,
      child: Hero(
        createRectTween: _createRectTween,
        tag: imageName,
        child: RadialExpansion(
          maxRadius: kMaxRadius,
          child: Photo(
            photo: imageName,
            onTap: () {
              Navigator.of(context).push(
                PageRouteBuilder<void>(
                  pageBuilder: (context, animation, secondaryAnimation) {
                    return AnimatedBuilder(
                      animation: animation,
                      builder: (context, child) {
                        return Opacity(
                          opacity: opacityCurve.transform(animation.value),
                          child: _buildPage(context, imageName, description),
                        );
                      },
                    );
                  },
                ),
              );
            },
          ),
        ),
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    timeDilation = 5.0; // 1.0 is normal animation speed.

    return Scaffold(
      appBar: AppBar(
        title: const Text('Radial Transition Demo'),
      ),
      body: Container(
        padding: const EdgeInsets.all(32),
        alignment: FractionalOffset.bottomLeft,
        child: Row(
          mainAxisAlignment: MainAxisAlignment.spaceBetween,
          children: [
            _buildHero(context, 'assets/images/01.jpg', 'Chair'),
            _buildHero(context, 'assets/images/02.jpg', 'Binoculars'),
            _buildHero(context, 'assets/images/03.jpg', 'Beach ball'),
            _buildHero(context, 'assets/images/04.jpg', 'Beach ball'),
          ],
        ),
      ),
    );
  }
}

class Photo extends StatelessWidget {
  const Photo({super.key, required this.photo, this.onTap});

  final String photo;
  final VoidCallback? onTap;

  @override
  Widget build(BuildContext context) {
    return Material(
      // Slightly opaque color appears where the image has transparency.
      color: Theme.of(context).primaryColor.withOpacity(0.25),
      child: InkWell(
        onTap: onTap,
        child: LayoutBuilder(
          builder: (context, size) {
            return Image.asset(
              photo,
              fit: BoxFit.contain,
            );
          },
        ),
      ),
    );
  }
}

class RadialExpansion extends StatelessWidget {
  const RadialExpansion({
    super.key,
    required this.maxRadius,
    this.child,
  }) : clipRectSize = 2.0 * (maxRadius / math.sqrt2);

  final double maxRadius;
  final double clipRectSize;
  final Widget? child;

  @override
  Widget build(BuildContext context) {
    // 控制形状变化的核心代码
    return ClipOval( // 圆形
      child: Center(
        child: SizedBox(
          width: clipRectSize,
          height: clipRectSize,
          child: ClipRect( // 矩形
            child: child,
          ),
        ),
      ),
    );
  }
}

页面转场动画

在自定义路由 时，添加动画，自定义路由需要用到PageRouteBuilder<T>；

import 'package:flutter/material.dart';

/// 为页面切换加入动画效果
class PageAnimation extends StatefulWidget {
  const PageAnimation({super.key});

  @override
  State<PageAnimation> createState() => _PageAnimationState();
}

class _PageAnimationState extends State<PageAnimation> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
          title: const Text(
        '为页面切换加入动画效果',
        style: TextStyle(fontSize: 20),
      )),
      body: SizedBox(
        width: MediaQuery.of(context).size.width,
        height: MediaQuery.of(context).size.height,
        child: Column(
          mainAxisAlignment: MainAxisAlignment.center,
          crossAxisAlignment: CrossAxisAlignment.center,
          children: [
            ElevatedButton(
                onPressed: () {
                  Navigator.of(context).push(_createRouteX());
                },
                child: const Text(
                  'X轴偏移',
                  style: TextStyle(fontSize: 20),
                )),
            ElevatedButton(
                onPressed: () {
                  Navigator.of(context).push(_createRouteY());
                },
                child: const Text(
                  'Y轴偏移',
                  style: TextStyle(fontSize: 20),
                )),
            ElevatedButton(
                onPressed: () {
                  Navigator.of(context).push(_createRouteMix());
                },
                child: const Text(
                  '混合动画',
                  style: TextStyle(fontSize: 20),
                )),
          ],
        ),
      ),
    );
  }

  /// X轴 平移动画，切换页面
  Route _createRouteX() {
    return PageRouteBuilder(
        // opaque: false, // 新页面，背景色不透明度
        pageBuilder: (context, animation, secondaryAnimation) => const TestPage01(),
        transitionsBuilder: (context, animation, secondaryAnimation, child) {
          const begin = Offset(1.0, 0.0); // 将 dx 参数设为 1，这代表在水平方向左切换整个页面的宽度
          const end = Offset.zero;
          const curve = Curves.ease;

          var tween =
              Tween(begin: begin, end: end).chain(CurveTween(curve: curve));

          return SlideTransition(
            position: animation.drive(tween),
            child: child,
          );
        });
  }

  /// Y轴 平移动画，切换页面
  Route _createRouteY() {
    return PageRouteBuilder(
        // opaque: false, // 新页面，背景色不透明度
        pageBuilder: (context, animation, secondaryAnimation) => const TestPage01(),
        transitionsBuilder: (context, animation, secondaryAnimation, child) {
          const begin = Offset(0.0, 1.0); // 将 dy 参数设为 1，这代表在竖直方向上切换整个页面的高度
          const end = Offset.zero;
          const curve = Curves.ease;

          var tween =
              Tween(begin: begin, end: end).chain(CurveTween(curve: curve));

          return SlideTransition(
            position: animation.drive(tween),
            child: child,
          );
        });
  }

  /// 多个动画配合，切换页面
  Route _createRouteMix() {
    return PageRouteBuilder(
        // opaque: false, // 新页面，背景色不透明度
        pageBuilder: (context, animation, secondaryAnimation) => const TestPage01(),
        transitionsBuilder: (context, animation, secondaryAnimation, child) {
          var tween = Tween<double>(begin: 0.1, end: 1.0)
              .chain(CurveTween(curve: Curves.ease));
          return FadeTransition(
            // 淡入淡出
            opacity: animation.drive(tween),
            child: RotationTransition(
              // 旋转
              turns: animation.drive(tween),
              child: ScaleTransition(
                // 更替
                scale: animation.drive(tween),
                child: child,
              ),
            ),
          );
        });
  }
}

class TestPage01 extends StatelessWidget {
  const TestPage01({super.key});

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: Colors.lightBlue,
      appBar: AppBar(
        title: const Text('TestPage01'),
      ),
    );
  }
}

交错动画

多个动画配合使用

这个案例是官方的，原汁原味；

import 'package:flutter/material.dart';
import 'package:flutter/scheduler.dart' show timeDilation;


class IntertwinedAnimation extends StatefulWidget {
  const IntertwinedAnimation({super.key});

  @override
  State<IntertwinedAnimation> createState() => _IntertwinedAnimationState();
}

class _IntertwinedAnimationState extends State<IntertwinedAnimation>
    with SingleTickerProviderStateMixin {

  late AnimationController _controller;

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

    _controller = AnimationController(
        duration: const Duration(milliseconds: 2000), vsync: this);
  }

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

  Future<void> _playAnimation() async {
    try {
      await _controller.forward().orCancel;
      await _controller.reverse().orCancel;
    } on TickerCanceled {}
  }

  @override
  Widget build(BuildContext context) {
    // timeDilation = 10.0;
    return Scaffold(
      appBar: AppBar(
          title: const Text(
        '交错动画',
        style: TextStyle(fontSize: 20),
      )),
      body: GestureDetector(
        behavior: HitTestBehavior.opaque,
        onTap: () {
          _playAnimation();
        },
        child: Center(
          child: Container(
            width: 300,
            height: 300,
            decoration: BoxDecoration(
                color: Colors.black.withOpacity(0.1),
                border: Border.all(
                  color: Colors.black.withOpacity(0.5),
                )),
            child: StaggerAnimation(controller: _controller),
          ),
        ),
      ),
    );
  }
}

class StaggerAnimation extends StatelessWidget {
  final Animation<double> controller;
  final Animation<double> opacity;
  final Animation<double> width;
  final Animation<double> height;
  final Animation<EdgeInsets> padding;
  final Animation<BorderRadius?> borderRadius;
  final Animation<Color?> color;

  StaggerAnimation({super.key, required this.controller})
      : opacity = Tween<double>(
          begin: 0.0,
          end: 1.0,
        ).animate(CurvedAnimation(
            parent: controller,
            curve: const Interval(
              0.0,
              0.100,
              curve: Curves.ease,
            ))),
        width = Tween<double>(
          begin: 50.0,
          end: 150.0,
        ).animate(CurvedAnimation(
            parent: controller,
            curve: const Interval(
              0.125,
              0.250,
              curve: Curves.ease,
            ))),
        height = Tween<double>(begin: 50.0, end: 150.0).animate(CurvedAnimation(
            parent: controller,
            curve: const Interval(
              0.250,
              0.375,
              curve: Curves.ease,
            ))),
        padding = EdgeInsetsTween(
          begin: const EdgeInsets.only(bottom: 16),
          end: const EdgeInsets.only(bottom: 75),
        ).animate(CurvedAnimation(
            parent: controller,
            curve: const Interval(
              0.250,
              0.375,
              curve: Curves.ease,
            ))),
        borderRadius = BorderRadiusTween(
          begin: BorderRadius.circular(4),
          end: BorderRadius.circular(75),
        ).animate(CurvedAnimation(
            parent: controller,
            curve: const Interval(
              0.375,
              0.500,
              curve: Curves.ease,
            ))),
        color = ColorTween(begin: Colors.indigo[100], end: Colors.orange[400])
            .animate(CurvedAnimation(
                parent: controller,
                curve: const Interval(
                  0.500,
                  0.750,
                  curve: Curves.ease,
                )));

  Widget _buildAnimation(BuildContext context, Widget? child) {
    return Container(
      padding: padding.value,
      alignment: Alignment.bottomCenter,
      child: Opacity(
        opacity: opacity.value,
        child: Container(
          width: width.value,
          height: height.value,
          decoration: BoxDecoration(
              color: color.value,
              border: Border.all(
                color: Colors.indigo[300]!,
                width: 3,
              ),
              borderRadius: borderRadius.value),
        ),
      ),
    );
  }

  @override
  Widget build(BuildContext context) {
    return AnimatedBuilder(
      builder: _buildAnimation,
      animation: controller,
    );
  }
}

依次执行动画

这个案例是根据官方demo改的，它那个太复杂了，不利于新手阅读（个人觉得）；

官方文档：flutter.cn/docs/cookbo...

import 'package:flutter/material.dart';

class Intertwined02Animation extends StatefulWidget {
  const Intertwined02Animation({super.key});

  @override
  State<Intertwined02Animation> createState() => _Intertwined02AnimationState();
}

class _Intertwined02AnimationState extends State<Intertwined02Animation> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: SizedBox(
        width: MediaQuery.of(context).size.width,
        height: MediaQuery.of(context).size.height,
        child: const TableList(),
        // child: const Column(
        //   crossAxisAlignment: CrossAxisAlignment.center,
        //   children: [
        //     TableList()
        //   ],
        // ),
      ),
    );
  }
}

class TableList extends StatefulWidget {
  const TableList({super.key});

  @override
  State<TableList> createState() => _TableListState();
}

class _TableListState extends State<TableList> with SingleTickerProviderStateMixin {

  /// 遍历循环写法
  late AnimationController _controller;

  final Duration _durationTime = const Duration(milliseconds: 3000);

  @override
  initState() {
    super.initState();
    _controller = AnimationController(vsync: this, duration: _durationTime);
    _controller.forward();
  }

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

  /// 遍历Interval
  List<Interval> _createInterval() {
    List<Interval> intervals = [];

    // Interval(0.0,0.5);
    // Interval(0.5,0.75);
    // Interval(0.75,1.0);

    double begin = 0.0;
    double end = 0.5;
    for (int i = 0; i < 3; i++) {
      if (i == 0) {
        intervals.add(Interval(begin, end));
      } else {
        begin = end;
        end = begin + 0.25;
        intervals.add(Interval(begin, end));
      }
      // debugPrint('begin：$begin --- end：$end');
    }
    return intervals;
  }

  /// 遍历循环组件
  List<Widget> _createWidget() {
    var intervals = _createInterval();

    List<Widget> listItems = [];

    for (int i = 0; i < 3; i++) {
      listItems.add(AnimatedBuilder(
        animation: _controller,
        builder: (context, child) {
          var animationPercent = Curves.easeOut.transform(intervals[i].transform(_controller.value));
          final opacity = animationPercent;
          final slideDistance = (1.0 - animationPercent) * 150;
          return Opacity(
              opacity: i == 2 ? opacity : 1,
              child: Transform.translate(
                offset: Offset(slideDistance, 100 + (i * 50)),
                child: child,
              ));
        },
        child: Container(
          width: 100,
          height: 50,
          color: Colors.lightBlue,
        ),
      ));
    }
    return listItems;
  }

  @override
  Widget build(BuildContext context) {
    return SizedBox(
      width: MediaQuery.of(context).size.width,
      height: MediaQuery.of(context).size.height,
      child: Column(
        children: _createWidget(),
      ),
    );
  }

  /// 非遍历循环写法
// late AnimationController _controller;
//
// final Interval _intervalA = const Interval(0.0, 0.5);
// final Interval _intervalB = const Interval(0.5, 0.8);
// final Interval _intervalC = const Interval(0.8, 1.0);
//
// final Duration _durationTime = const Duration(milliseconds: 3000);
//
// @override
// void initState() {
//   super.initState();
//   _controller = AnimationController(vsync: this, duration: _durationTime);
//   _controller.forward();
// }
//
// @override
// void dispose() {
//   _controller.dispose();
//   super.dispose();
// }
//
// @override
// Widget build(BuildContext context) {
//   return SizedBox(
//     width: MediaQuery.of(context).size.width,
//     height: MediaQuery.of(context).size.height,
//     child: Column(
//       children: [
//         AnimatedBuilder(
//           animation: _controller,
//           builder: (context,child) {
//             var animationPercent = Curves.easeOut.transform(_intervalA.transform(_controller.value));
//             final slideDistance = (1.0 - animationPercent) * 150;
//             return Transform.translate(
//               offset: Offset(slideDistance,100),
//               child: child
//             );
//           },
//           child: Container(
//             width: 100,
//             height: 50,
//             color: Colors.lightBlue,
//           ),
//         ),
//         AnimatedBuilder(
//           animation: _controller,
//           builder: (context,child) {
//             var animationPercent = Curves.easeOut.transform(_intervalB.transform(_controller.value));
//             final slideDistance = (1.0 - animationPercent) * 150;
//             return Transform.translate(
//                 offset: Offset(slideDistance,150),
//                 child: child
//             );
//           },
//           child: Container(
//             width: 100,
//             height: 50,
//             color: Colors.lightBlue,
//           ),
//         ),
//         AnimatedBuilder(
//           animation: _controller,
//           builder: (context,child) {
//             var animationPercent = Curves.easeOut.transform(_intervalC.transform(_controller.value));
//             final opacity = animationPercent;
//             final slideDistance = (1.0 - animationPercent) * 150;
//             return Opacity(
//               opacity: opacity,
//               child: Transform.translate(
//                   offset: Offset(slideDistance,200),
//                   child: child
//               ),
//             );
//           },
//           child: Container(
//             width: 100,
//             height: 50,
//             color: Colors.lightBlue,
//           ),
//         ),
//       ],
//     ),
//   );
// }

  /// 基础版本写法
// late AnimationController _controller;
// final Duration _durationTime = const Duration(milliseconds: 2000);
// // 0.0 - 1.0 / 0% - 100%
// final Interval _interval = const Interval(0.5, 1.0); // 延迟 50% 再开始 启动动画，执行到 100%
// // final Interval _interval = const Interval(0.5, 0.7); // 延迟 50% 再开始 启动动画，后期的执行速度，增加 30%
// // final Interval _interval = const Interval(0.0, 0.1); // 不延迟 动画执行速度，增加 90%
//
// @override
// void initState() {
//   super.initState();
//   _controller = AnimationController(vsync: this, duration: _durationTime);
//   _controller.forward();
// }
//
// @override
// void dispose() {
//   _controller.dispose();
//   super.dispose();
// }

// @override
// Widget build(BuildContext context) {
//   return AnimatedBuilder(
//       animation: _controller,
//       builder: (context,child) {
//         // var animationPercent = Curves.easeOut.transform(_controller.value); // 加动画曲线
//         // var animationPercent = _interval.transform(_controller.value); // 加动画间隔
//         var animationPercent = Curves.easeOut.transform(_interval.transform(_controller.value)); // 动画曲线 + 动画间隔
//
//         final slideDistance = (1.0 - animationPercent) * 150; // 就是对150 做递减
//         // debugPrint('animationPercent：$animationPercent --- slideDistance：$slideDistance');
//         debugPrint('slideDistance：$slideDistance');
//
//         return Transform.translate(
//           offset: Offset(0,slideDistance),
//           child: child
//         );
//       },
//     child: Container(
//       width: 100,
//       height: 50,
//       color: Colors.lightBlue,
//     ),
//   );
// }
}

官方文档

flutter.cn/docs/ui/ani...