dart - How to rotate an image using Flutter AnimationController and Transform?

Question

I have star png image and I need to rotate the star using Flutter AnimationController and Transformer. I couldn't find any documents or example for image rotation animation.

Any idea How to rotate an image using Flutter AnimationController and Transform?

UPDATE:

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

Full example (null safe):

Press "go" makes the star icon spin until you press "stop".

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(),
            ),
          ],
        ),
      ),
    );
  }
}

Step by step guide:

First, let your widget state class implement SingleTickerProviderStateMixin.

Secondly, define an AnimationController and don't forget to dispose it. If you are not yet using null-safe, remove the late keyword.

late AnimationController _controller;

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

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

Then wrap your Widget with RotationTransition.

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

Finally, call methods on the AnimationController to start/stop animation.

• Run the animation once, use .forward
• Loop the animation, use .repeat
• Stop immediately, use .stop
• Stop and set it back to original rotation, use .reset
• Stop and animate to a rotation value, use .animateTo