AnimationController constructor

AnimationController({double value, Duration duration, String debugLabel, double lowerBound: 0.0, double upperBound: 1.0, AnimationBehavior animationBehavior: AnimationBehavior.normal, @required TickerProvider vsync })

Creates an animation controller.

  • value is the initial value of the animation. If defaults to the lower bound.

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

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

  • lowerBound is the smallest value this animation can obtain and the value at which this animation is deemed to be dismissed. It cannot be null.

  • upperBound is the largest value this animation can obtain and the value at which this animation is deemed to be completed. It cannot be null.

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

Implementation 

AnimationController({
  double value,
  this.duration,
  this.debugLabel,
  this.lowerBound = 0.0,
  this.upperBound = 1.0,
  this.animationBehavior = AnimationBehavior.normal,
  @required TickerProvider vsync,
}) : assert(lowerBound != null),
     assert(upperBound != null),
     assert(upperBound >= lowerBound),
     assert(vsync != null),
     _direction = _AnimationDirection.forward {
  _ticker = vsync.createTicker(_tick);
  _internalSetValue(value ?? lowerBound);
}