ios - Cancel UIScrollView bounce after dragging

Question

I have a horizontal UIScrollView. I want to do a variation of the "pull-to-reset" animation, where I pull all the way past the right edge of the scroll view's content size, release my finger, and have the scroll view fly back to (0, 0) content offset.

My delegate method looks like this:

- (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate {
    //check if it exceeds a certain critical value
    if (scrollView.contentOffset.x - (scrollView.contentSize.width - IMAGE_WIDTH) > 80) {
        [self doAnimatedScrollTo:CGPointMake(0, 0)];
    }
}

where doAnimatedScrollTo: is a custom animation method necessary because I want to control the duration of the animation.

While this works, it seems that the animation is queued up. The UIScrollView "bounce" animation happens first, then my animation occurs.

Is there a way to cancel the bounce animation, keep the content offset from "snapping" back, and then perform my animation?

Answer 1

try this

- (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate {
  //check if it exceeds a certain critical value
  if (scrollView.contentOffset.x - (scrollView.contentSize.width - IMAGE_WIDTH) > 80) {
    [scrollView setContentOffset:CGPointMake(0, 0) animated:YES];
  }
}