Future<Null> animateTo({GlobalKey targetKey, Duration duration, Curve curve: Curves.linear })

Animate the entry to the location of the widget that has the given target key.

The animation will take place over the given duration and will apply the given curve.

This function can only be called once per overlay entry.

Source 

Future<Null> animateTo({
  GlobalKey targetKey,
  Duration duration,
  Curve curve: Curves.linear
}) {
  assert(_handle != null);
  assert(_overlayEntry != null);
  assert(targetKey != null);
  assert(duration != null);
  assert(curve != null);
  _targetKey = targetKey;
  _curve = curve;
  // TODO(abarth): Support changing the animation target when in flight.
  assert(_controller == null);
  // TODO(ianh): Need to get a TickerProvider that's tied to the Overlay's TickerMode.
  _controller = new AnimationController(duration: duration, vsync: _overlay)
    ..addListener(_overlayEntry.markNeedsBuild);
  return _controller.forward();
}