custom repeating scaling animation

Question

i am trying to achieved a scaling animation that starts from 0 to 1 and then alternates between 0.8 and 1. i copied the code from https://api.flutter.dev/flutter/widgets/ScaleTransition-class.html and tweaked the values but am unable to achieve my desired animation. the below code starts from 0.8 and animates to 1 and repeats. any ideas on how i can achieve the mentioned animation? tia

late final AnimationController _controller = AnimationController(
    value: 0,
    duration: const Duration(seconds: 2),
    vsync: this,
  )..repeat(min: 0.8, max: 1, reverse: true);
  late final Animation<double> _animation = CurvedAnimation(
    parent: _controller,
    curve: Curves.fastOutSlowIn,
  );

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

Answer 1

try this:

late final AnimationController _controller = AnimationController(
        duration: const Duration(seconds: 2),
        value: 0,
        vsync: this,
      )..addStatusListener((status) async {
          if (status == AnimationStatus.completed) {
            _controller.animateBack(0.5);
            _controller.animateTo(1);
            _controller.repeat(min: 0.5, max: 1, reverse: true);
          }
        });
      late final Animation<double> _animation = CurvedAnimation(
        parent: _controller,
        curve: Curves.fastOutSlowIn,
      );

Full sample:

class _MainAppState extends State<MainApp> with TickerProviderStateMixin {
      late final AnimationController _controller = AnimationController(
        duration: const Duration(seconds: 2),
        value: 0,
        vsync: this,
      )..addStatusListener((status) async {
          if (status == AnimationStatus.completed) {
            _controller.animateBack(0.5);
            _controller.animateTo(1);
            _controller.repeat(min: 0.5, max: 1, reverse: true);
          }
        });
      late final Animation<double> _animation = CurvedAnimation(
        parent: _controller,
        curve: Curves.fastOutSlowIn,
      );
    
      @override
      void initState() {
        super.initState();
      }
    
      @override
      void dispose() {
        _controller.dispose();
        super.dispose();
      }
    
      @override
      Widget build(BuildContext context) {
        return MaterialApp(
          home: Scaffold(
            body: Center(
              child: ScaleTransition(
                scale: _animation,
                child: const Padding(
                  padding: EdgeInsets.all(8.0),
                  child: FlutterLogo(size: 150.0),
                ),
              ),
            ),
          ),
        );
      }
    }