@Override
protected void dispatchDraw(Canvas canvas) {
super.dispatchDraw(canvas);
if (mFolder == null) return;
if (mFolder.getItemCount() == 0 && !mAnimating) return;
ArrayList<View> items = mFolder.getItemsInReadingOrder(false);
Drawable d;
TextView v;
// Update our drawing parameters if necessary
if (mAnimating) {
computePreviewDrawingParams(mAnimParams.drawable);
} else {
v = (TextView) items.get(0);
d = v.getCompoundDrawables()[1];
computePreviewDrawingParams(d);
}
int nItemsInPreview = Math.min(items.size(), NUM_ITEMS_IN_PREVIEW);
if (!mAnimating) {
for (int i = nItemsInPreview - 1; i >= 0; i--) {
v = (TextView) items.get(i);
d = v.getCompoundDrawables()[1];
mParams = computePreviewItemDrawingParams(i, mParams);
mParams.drawable = d;
drawPreviewItem(canvas, mParams);
}
} else {
drawPreviewItem(canvas, mAnimParams);
}
}
private void animateFirstItem(final Drawable d, int duration) {
computePreviewDrawingParams(d);
final PreviewItemDrawingParams finalParams = computePreviewItemDrawingParams(0, null);
final float scale0 = 1.0f;
final float transX0 = (mAvailableSpaceInPreview - d.getIntrinsicWidth()) / 2;
final float transY0 = (mAvailableSpaceInPreview - d.getIntrinsicHeight()) / 2;
mAnimParams.drawable = d;
ValueAnimator va = ValueAnimator.ofFloat(0f, 1.0f);
va.addUpdateListener(
new AnimatorUpdateListener() {
public void onAnimationUpdate(ValueAnimator animation) {
float progress = (Float) animation.getAnimatedValue();
mAnimParams.transX = transX0 + progress * (finalParams.transX - transX0);
mAnimParams.transY = transY0 + progress * (finalParams.transY - transY0);
mAnimParams.scale = scale0 + progress * (finalParams.scale - scale0);
invalidate();
}
});
va.addListener(
new AnimatorListenerAdapter() {
@Override
public void onAnimationStart(Animator animation) {
mAnimating = true;
}
@Override
public void onAnimationEnd(Animator animation) {
mAnimating = false;
}
});
va.setDuration(duration);
va.start();
}
