UIPageViewController didFinishAnimating not called if swiped quickly

Question

I have a UIPageViewController that works as expected. I can scroll left and right and the delegate method didFinishAnimating is called when I scroll each direction. However, if I scroll too quickly I end up on a page where didFinishAnimating is not called, though it is called for all previous pages. Does anyone know why this might be happening?

I would think that didFinishAnimating would be called on every page transition regardless (e.g., even if the turn was aborted).

Answer 1

This bug is still here in 2017.. I tried many alternative ways.. now I gave up the hope that this will be fixed by Apple and I think the best way is to use protocol to bound UIPageViewController with content ViewController, so we can notify UIPageViewController in viewDidAppear()

Answer 2

I've got the same issue. I tried to use the UIScrollView delegate instead of UIPageViewController to solve the issue. This is a tricky method, not recommend to use.

1.get the UIScrollView in UIPageViewController to set delegate:

for (UIView *view in self.view.subviews) {
    if ([view isKindOfClass:[UIScrollView class]]) {
        UIScrollView *scroll = (UIScrollView *) view;
        scroll.delegate = self;
    }
}

2.override scrollViewWillBeginDragging:(UIScrollView *)scrollView

- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView{
    [[NSNotificationCenter defaultCenter] postNotificationName:PageSwitchingBegan
                                                    object:nil];
}
- (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate {
    [[NSNotificationCenter defaultCenter] postNotificationName:PageSwitchingEnded
                                                    object:nil];
}

You may also try override - (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView instead of scrollViewDidEndDragging to achieve better result.