问重用AnimationController

EN

child: new GestureDetector(
   onDoubleTap: () {
    _controller.forward();
  },
  child: ...
}

  AnimationController _controller;

  @override
  void initState() {
    super.initState();
    _controller = new AnimationController(
      duration: const Duration(seconds: 1),
      vsync: this,
    );
  }

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