如何使用 Flutter AnimationController 和 Transform 旋转图像？

Question

我有星星 png 图片，我需要使用 Flutter AnimationController 和 Transformer 旋转星星。我找不到图像旋转动画的任何文档或示例。

知道如何使用 Flutter AnimationController 和 Transform 旋转图像吗？

更新：

class _MyHomePageState extends State<MyHomePage>  with TickerProviderStateMixin {

  AnimationController animationController;

  @override
  void initState() {
    super.initState();
    animationController = new AnimationController(
      vsync: this,
      duration: new Duration(milliseconds: 5000),
    );
    animationController.forward();
    animationController.addListener(() {
      setState(() {
        if (animationController.status == AnimationStatus.completed) {
          animationController.repeat();
        }
      });
    });
  }

  @override
  Widget build(BuildContext context) {
    return new Container(
      alignment: Alignment.center,
      color: Colors.white,
      child: new AnimatedBuilder(
        animation: animationController,
        child: new Container(
          height: 80.0,
          width: 80.0,
          child: new Image.asset('images/StarLogo.png'),
        ),
        builder: (BuildContext context, Widget _widget) {
          return new Transform.rotate(
            angle: animationController.value,
            child: _widget,
          );
        },
      ),
    );
  }
}

Answer 1

这是我旋转图像的例子。我不知道 - 但也许它适合你

AnimationController rotationController;

@override
void initState() {
  rotationController = AnimationController(duration: const Duration(milliseconds: 500), vsync: this);
  super.initState();
}
//...
RotationTransition(
  turns: Tween(begin: 0.0, end: 1.0).animate(rotationController),
  child: ImgButton(...)
//...
rotationController.forward(from: 0.0); // it starts the animation

UPD - 如何用 Transform.rotate

解决问题

在你的例子中，所有的工作都和你写的完全一样——它将图像从 0.0 旋转到 1.0（它是 AnimationController 的默认参数）。对于整圈，您必须将上部参数设置为 2 * pi（来自 math 包）

import 'dart:math';
//...
animationController = AnimationController(vsync: this, duration: Duration(seconds: 5), upperBound: pi * 2);

Answer 2

完整示例（空安全）：

按“开始”使星形图标旋转，直到您按“停止”。

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 {
  @override
  _MyHomePageState createState() => _MyHomePageState();
}

class _MyHomePageState extends State<MyHomePage>
    with SingleTickerProviderStateMixin {
  late AnimationController _controller;

  @override
  void initState() {
    _controller = AnimationController(
      duration: const Duration(milliseconds: 5000),
      vsync: this,
    );
    super.initState();
  }

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

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text("Demo"),
      ),
      body: Center(
        child: Column(
          children: <Widget>[
            RotationTransition(
              turns: Tween(begin: 0.0, end: 1.0).animate(_controller),
              child: Icon(Icons.stars),
            ),
            ElevatedButton(
              child: Text("go"),
              onPressed: () => _controller.forward(),
            ),
            ElevatedButton(
              child: Text("reset"),
              onPressed: () => _controller.reset(),
            ),
          ],
        ),
      ),
    );
  }
}

分步指南：

首先，让您的小部件状态 class 实现 SingleTickerProviderStateMixin。

其次，定义一个AnimationController并且不要忘记处理它。如果您还没有使用 null-safe，请删除 late 关键字。

late AnimationController _controller;

@override
void initState() {
  _controller = AnimationController(
    duration: const Duration(milliseconds: 5000),
    vsync: this,
  );
  super.initState();
}

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

然后用 RotationTransition 包裹你的 Widget。

RotationTransition(
  turns: Tween(begin: 0.0, end: 1.0).animate(_controller),
  child: Icon(Icons.stars),
),

最后，调用 AnimationController 到 start/stop 动画的方法。

运行动画一次，使用.forward
循环动画，使用.repeat
立即停止，使用.stop
停止并将其设置回原始旋转，使用.reset
停止并动画到旋转值，使用.animateTo

Answer 3

这里我一次旋转 3 张图片...保存在资产文件夹中的图片...如果您愿意也可以使用网络图片...我在这里以 3 种速度旋转 3 张图片...

import 'package:flutter/material.dart';
import 'package:fynd/services/auth.dart';
import 'dart:async';
import 'package:fynd/services/cons.dart';

class SplashScreen extends StatefulWidget {
  _SplashScreen createState() => new _SplashScreen();
}

class _SplashScreen extends State<StatefulWidget>
    with SingleTickerProviderStateMixin {
  AnimationController animationController;

  @override
  void initState() {
    super.initState();
    animationController = new AnimationController(
      vsync: this,
      duration: new Duration(seconds: 5),
    );

    animationController.repeat();
  }

  @override
  Widget build(BuildContext context) {

    return new Container(
      alignment: Alignment.center,
      color: Colors.white,
      child: new AnimatedBuilder(
        animation: animationController,
        child: new Container(
          decoration: BoxDecoration(
              image: DecorationImage(
                  image: AssetImage('assets/images/splash_circle3.png'))),
          child: new AnimatedBuilder(
            animation: animationController,
            child: new Container(
              decoration: BoxDecoration(
                  image: DecorationImage(
                      image: AssetImage('assets/images/splash_circle2.png'))),
              child: new AnimatedBuilder(
                  animation: animationController,
                  child: Container(
                      child: Container(
                    decoration: BoxDecoration(
                        image: DecorationImage(
                            image: AssetImage(
                                'assets/images/splash_circle1.png'))),
                  )),
                  builder: (BuildContext context, Widget _widget) {
                    return new Transform.rotate(
                      angle: animationController.value * 4,
                      child: _widget,
                    );
                  }),
            ),
            builder: (BuildContext context, Widget _widget) {
              return new Transform.rotate(
                angle: animationController.value * 5,
                child: _widget,
              );
            },
          ),
        ),
        builder: (BuildContext context, Widget _widget) {
          return new Transform.rotate(
            angle: animationController.value * 6,
            child: _widget,
          );
        },
      ),
    );
  }
}

Answer 4

这里我将动画生成器放在 Stack 中。然后你可以动画图像向右旋转（顺时针）和向左旋转（逆时针）。

import 'package:flutter/material.dart';
import 'package:fynd/services/auth.dart';
import 'dart:async';
import 'package:fynd/services/cons.dart';

class SplashScreen extends StatefulWidget {
  _SplashScreen createState() => new _SplashScreen();
}

class _SplashScreen extends State<StatefulWidget>
    with SingleTickerProviderStateMixin {
  AnimationController animationController;

  @override
  void initState() {
    super.initState();
    animationController = new AnimationController(
      vsync: this,
      duration: new Duration(seconds: 5),
    );

    animationController.repeat();

  }

  @override
  Widget build(BuildContext context)

    return new Container(
      alignment: Alignment.center,
      color: Colors.white,

      child: new Stack(children: <Widget>[

        new AnimatedBuilder(
          animation: animationController,
          child :Container(
            decoration: BoxDecoration(
                image: DecorationImage(image: AssetImage('assets/images/splash_circle3.png'),fit: BoxFit.cover)),

          ),
          builder: (BuildContext context, Widget _widget) {
            return new Transform.rotate(
              angle: animationController.value * 10,
              child: _widget,
            );
          },
        ),

       new AnimatedBuilder(
        animation: animationController,
        child: Container(
          decoration: BoxDecoration(
              image: DecorationImage(image: AssetImage('assets/images/splash_circle2.png'),fit: BoxFit.cover)),

        ),
        builder: (BuildContext context, Widget _widget) {
          return new Transform.rotate(
            angle: -animationController.value * 10,
            child: _widget,
          );
        },
       ),

        new AnimatedBuilder(
            animation: animationController,
           child: Container(
              decoration: BoxDecoration(
                  image: DecorationImage(image: AssetImage('assets/images/splash_circle1.png'), fit: BoxFit.cover)),
            ),
            builder: (BuildContext context, Widget _widget) {
              return new Transform.rotate(
                angle: animationController.value * 10,
                child: _widget,
              );
            }),

      ],),
    );
  }
}

Answer 5

屏幕截图（空安全）

完整代码：

import 'dart:math' as math;

class _FooPageState extends State<FooPage> with SingleTickerProviderStateMixin{
  late final AnimationController _controller = AnimationController(vsync: this, duration: Duration(seconds: 2))..repeat();

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: Center(
        child: AnimatedBuilder(
          animation: _controller,
          builder: (_, child) {
            return Transform.rotate(
              angle: _controller.value * 2 * math.pi,
              child: child,
            );
          },
          child: FlutterLogo(size: 200),
        ),
      ),
    );
  }
}

Answer 6


    _controller = AnimationController(duration: const Duration(seconds: 3), vsync: this);
    _animation = Tween(begin: 0.0, end: 250.0).animate(_controller)
      ..addListener(() {
        setState(() {});
      })
      ..addStatusListener((state) {
        if (state == AnimationStatus.completed) {
          print("complete");
        }
      });
    _controller.forward();

    new Future.delayed(
        const Duration(seconds: 5),
            () => Navigator.push(
          context,
          MaterialPageRoute(builder: (context) => SignScreen()),
        ));

Answer 7

class _MyHomePageState extends State<MyHomePage>  with TickerProviderStateMixin {

  AnimationController animationController;

  @override
  void initState() {
    super.initState();
    animationController = new AnimationController(
      vsync: this,
      duration: new Duration(milliseconds: 5000),
    );
    animationController.repeat();

  }

  @override
  Widget build(BuildContext context) {
    return new Container(
      alignment: Alignment.center,
      color: Colors.white,
      child: RotationTransition(
              child: Icon(Icons.refresh),
              turns: controller,
            )
    );
  }
}

Answer 8

full example just call ImageAnimateRotate( your widget )

class ImageAnimateRotate extends StatefulWidget {
  final Widget child;
  const ImageAnimateRotate({Key? key, required this.child}) : super(key: key);

  @override
  _ImageAnimateRotateState createState() => _ImageAnimateRotateState();
}

class _ImageAnimateRotateState extends State<ImageAnimateRotate> with SingleTickerProviderStateMixin {
  late final AnimationController _controller;

  @override
  void initState() {
    super.initState();
    _controller = AnimationController(vsync: this, duration: Duration(seconds: 20))..repeat();
  }

  @override
  Widget build(BuildContext context) {
    return Center(
      child: AnimatedBuilder(
        animation: _controller,
        builder: (_, child) {
          return Transform.rotate(
            angle: _controller.value * 2 * math.pi,
            child: child,
          );
        },
        child: widget.child,
      ),
    );
  }
}

Answer 9

Flutter 也有小部件 AnimatedRotation (docs) 这使得旋转东西更容易。

你只需要一个double来设置旋转的状态。它以旋转的百分比工作，如果将其转换为度数，它将是 0.0 = 0deg、1.0 = 360deg

double turns = 0.0;

AnimatedRotation(
  duration: const Duration(milliseconds: 500),
  turns: turns,
  child: const Icon(Icons.refresh),
)

旋转只需要更新状态，Flutter会自动执行动画

void _changeRotation() {
  setState(() => turns += 1.0 / 8.0);
}

从 Flutter 文档中获取的用于旋转 flutter Logo 的完整示例

class LogoRotate extends StatefulWidget {
  const LogoRotate({Key? key}) : super(key: key);

  @override
  State<LogoRotate> createState() => LogoRotateState();
}

class LogoRotateState extends State<LogoRotate> {
  double turns = 0.0;

  void _changeRotation() {
    setState(() => turns += 1.0 / 8.0);
  }

  @override
  Widget build(BuildContext context) {
    return Column(
      mainAxisAlignment: MainAxisAlignment.center,
      children: <Widget>[
        ElevatedButton(
          onPressed: _changeRotation,
          child: const Text('Rotate Logo'),
        ),
        Padding(
          padding: const EdgeInsets.all(50),
          child: AnimatedRotation(
            turns: turns,
            duration: const Duration(seconds: 1),
            child: const FlutterLogo(),
          ),
        ),
      ],
    );
  }
}

如何使用 Flutter AnimationController 和 Transform 旋转图像？

How to rotate an image using Flutter AnimationController and Transform?

flutter

dart

flutter-layout

transform

flutter-animation