initAnimation method
void
initAnimation()
Implementation
void initAnimation() {
controller =
AnimationController(duration: Duration(milliseconds: 150), vsync: this);
offsetAnimation = Tween<double>(begin: -1, end: 0)
.animate(CurvedAnimation(parent: controller, curve: Curves.ease))
..addListener(() {
this.setState(() {});
});
// 播放
controller.forward();
}