Specifies that a panel can animate between layouts.

The normal use pattern is to set all childrens' positions, then to call {@link #animate(int)} to move them to their new positions over some period of time.

abstract class AnimatedLayout {

 /**
  * Layout children, animating over the specified period of time.
  *
  * <p>
  * This method provides a callback that will be informed of animation updates.
  * This can be used to create more complex animation effects.
  * </p>
  *
  * @param duration the animation duration, in milliseconds
  * @param callback the animation callback
  */
 void animate(int duration, [LayoutAnimationCallback callback = null]);

 /**
  * Layout children immediately.
  *
  * <p>
  * This is not normally necessary, unless you want to update child widgets'
  * positions explicitly to create a starting point for a subsequent call to
  * {@link #animate(int)}.
  * </p>
  *
  * @see #animate(int)
  * @see #animate(int, Layout.AnimationCallback)
  */
 void forceLayout();
}