AnimationController.unbounded({double value: 0.0, Duration duration, String debugLabel, @required TickerProvider vsync })

Creates an animation controller with no upper or lower bound for its value.

  • value is the initial value of the animation.

  • duration is the length of time this animation should last.

  • debugLabel is a string to help identify this animation during debugging (used by toString).

  • vsync is the TickerProvider for the current context. It can be changed by calling resync. It is required and cannot be null. See TickerProvider for advice on obtaining a ticker provider.

This constructor is most useful for animations that will be driven using a physics simulation, especially when the physics simulation has no pre-determined bounds.

Source 

AnimationController.unbounded({
  double value: 0.0,
  this.duration,
  this.debugLabel,
  @required TickerProvider vsync,
}) : lowerBound = double.NEGATIVE_INFINITY,
     upperBound = double.INFINITY {
  assert(value != null);
  assert(vsync != null);
  _direction = _AnimationDirection.forward;
  _ticker = vsync.createTicker(_tick);
  _internalSetValue(value);
}