Creates an animation controller.
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value
is the initial value of the animation. If defaults to the lower bound. -
duration is the length of time this animation should last.
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debugLabel is a string to help identify this animation during debugging (used by toString).
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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.
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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.
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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.
Source
AnimationController({ double value, this.duration, this.debugLabel, this.lowerBound: 0.0, this.upperBound: 1.0, @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); }