Listen for an animation to complete - animation

Question

I'm trying to perform an action after my animation finishes. I tried adding a statusListener but that is not working for me. My code looks like this:
#override
void initState() {
super.initState();
_controller = new AnimationController(
duration: new Duration(milliseconds: 500),
vsync: this,
)..addStatusListener((AnimationStatus status) {
print("Going");
if (status.index == 3 && spins > 0) { // AnimationStatus index 3 == completed animation
_controller.duration = new Duration(milliseconds: speed - 50);
_controller.forward(from: _controller.value == null ? 0.0 : 1 - _controller.value);
spins--;
print(speed);
}
});
}
The print(Going); never gets executed but my animation does end. What is going wrong?
///---Edit---///
I'm using an AnimatedBuilder, that part of the code looks like this:
child: new AnimatedBuilder(
animation: _controller,
child: new Image.network(widget.url),
builder: (BuildContext context, Widget child) {
return new Transform.rotate(
angle: _controller.value * 2.0 * math.PI,
child: child,
);
},
),

Answer 1

Reacting to your comment and edit I looked into the AnimationBuilder. Adapting the example in the docs I came up with this working solution:
class Spinner extends StatefulWidget {
#override
_SpinnerState createState() => new _SpinnerState();
}
class _SpinnerState extends State<Spinner> with SingleTickerProviderStateMixin {
AnimationController _controller;
CurvedAnimation _animation;
#override
void initState() {
super.initState();
_controller = new AnimationController(
duration: const Duration(seconds: 5),
vsync: this,
)..forward();
_animation = new CurvedAnimation(
parent: _controller,
curve: Curves.linear,
)..addStatusListener((AnimationStatus status) {
if (status == AnimationStatus.completed)
print('completed');
});
}
#override
void dispose() {
_controller.dispose();
super.dispose();
}
#override
Widget build(BuildContext context) {
return new AnimatedBuilder(
animation: _animation,
child: new Container(width: 200.0, height: 200.0, color: Colors.green),
builder: (BuildContext context, Widget child) {
return new Transform.rotate(
angle: _controller.value * 2.0 * 3.1415,
child: child,
);
},
);
}
}
As you can see, I used the controller as parent to an animation, which was than used as animation for the AnimationBuilder. Hope it helps.

Answer 2

You can also use the whenComplete listener
_animationController.forward().whenComplete((){
//Trigger different responses, when animation is started at different places.
})

Answer 3

Following the example in the flutter gallery's progress indicators you should attach the StatusListener to an animation, not the controller
_controller = AnimationController(
duration: const Duration(milliseconds: 1500),
vsync: this,
)..forward();
_animation = CurvedAnimation(
parent: _controller,
curve: const Interval(0.0, 0.9, curve: Curves.fastOutSlowIn),
reverseCurve: Curves.fastOutSlowIn
)..addStatusListener((AnimationStatus status) {
if (status == AnimationStatus.dismissed)
_controller.forward();
else if (status == AnimationStatus.completed)
_controller.reverse();
});
I have not tested this with your code. Just shout, if it doesn't work ;)