So I got two pages: The first page is my HomePage from where I can access my second page via a button. The second page is where I put an animated Icon inside. I'm trying to animate the icon and so far everything works just well. The icon bounces just like I want it to be but as soon as I go back to my HomePage all of a sudden an error appears and the app doesn't function anymore (I've added a screenshot but I don't really understand what I need to change inside of my code). What can I do to prevent this from happening?

This is my code:

class InfoScreen extends StatefulWidget {
  @override
  _InfoScreen createState() => _InfoScreen();
}
@override
class _InfoScreen extends State<InfoScreen> with TickerProviderStateMixin {
  AnimationController _animationController;
  Animation<double> _animation;
  bool _isPlaying = false;

  void _animate() {
    if (_isPlaying)
      _animationController.stop();
    else
      _animationController.forward();
    setState(() {
      _isPlaying = !_isPlaying;
    });
  }

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

    _animationController = AnimationController(
      vsync: this,
      duration: Duration(milliseconds: 450),
    );

    _animation = Tween<double>(begin: 0.85, end: 1.05).animate(
        CurvedAnimation(parent: _animationController, curve: Curves.easeIn));
    _animationController.forward();
    _animation.addStatusListener((status) {
      if (status == AnimationStatus.completed)
        _animationController.reverse();
      else if (status == AnimationStatus.dismissed)
        _animationController.forward();
    });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Info'),
        flexibleSpace: Container(
          decoration: BoxDecoration(
            gradient: LinearGradient(
                colors: [Color(0xffFBD23E), Color(0xffF6BE03)],
                begin: Alignment.topCenter,
                end: Alignment.bottomCenter),
          ),
        ),
      ),
      body: Container(
        constraints: BoxConstraints.expand(),
        decoration: BoxDecoration(
          gradient: LinearGradient(
              colors: [Color(0xffFEFDFD), Color(0xffBDBDB2)],
              begin: Alignment.topLeft,
              end: Alignment.bottomRight),
        ),
        child: ScaleTransition(
              scale: _animation,
              child: Icon(
                Icons.favorite,
                color: Color(0xffF40930),
              ),
            ),
 ],
        ),
      ),
    );
  }
}

CodePudding user response：

We need to dispose the AnimationController. Override the dispose method and dispose the _animationController.

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