/// <summary>
/// Builds the AnimatorSet that will create the expanding animation - the user will perceive the thumbnail getting bigger.
/// </summary>
/// <param name="expandedView">This is the ImageView that the thumbnail will scale up to.</param>
/// <param name="startBounds">The visible rectangle of the thumbnail (global coordinates).</param>
/// <param name="finalBounds">The visible rectangle of the full sized image (global coordinates).</param>
/// <param name="startScale"></param>
/// <returns></returns>
private AnimatorSet BuildExpandingAnimatorSet(ImageView expandedView, Rect startBounds, Rect finalBounds, float startScale)
{
// Each expanding animator is unique to the start location - we'll cache the AnimatorSet
// instance based on the starting location.
int key = startBounds.GetHashCode ();
if (_expandingAnimators.ContainsKey(key))
{
return _expandingAnimators[key];
}
AnimatorSet expandSet = new AnimatorSet();
expandSet.Play(ObjectAnimator.OfFloat(expandedView, View.X, startBounds.Left, finalBounds.Left))
.With(ObjectAnimator.OfFloat(expandedView, View.Y, startBounds.Top, finalBounds.Top))
.With(ObjectAnimator.OfFloat(expandedView, "ScaleX", startScale, 1f))
.With(ObjectAnimator.OfFloat(expandedView, "ScaleY", startScale, 1f));
expandSet.SetDuration(_shortAnimationDuration);
expandSet.SetInterpolator(new DecelerateInterpolator());
expandSet.AnimationEnd += NullOutCurrentAnimator;
expandSet.AnimationCancel += NullOutCurrentAnimator;
_expandingAnimators.Add(key, expandSet);
return expandSet;
}