animateTo method

TickerFuture animateTo (double target, { Duration duration, Curve curve: Curves.linear })

Drives the animation from its current value to target.

Returns a TickerFuture that completes when the animation is complete.

The most recently returned TickerFuture, if any, is marked as having been canceled, meaning the future never completes and its TickerFuture.orCancel derivative future completes with a TickerCanceled error.

During the animation, status is reported as AnimationStatus.forward regardless of whether target > value or not. At the end of the animation, when target is reached, status is reported as AnimationStatus.completed.

Implementation 

TickerFuture animateTo(double target, { Duration duration, Curve curve = Curves.linear }) {
  _direction = _AnimationDirection.forward;
  return _animateToInternal(target, duration: duration, curve: curve);
}