This has been a bit of a interesting one.
So I have a OpenGl screen with a scrollview on top. I Use a CADisplay link to update the render when I scroll (code below) which works really well.
However, I can't get it to snap to a point (animated). I believe the releasing of the CADisplay link stops the animation of the scrollview (see snapToItem).
I tried firing off the release of the CADisplay 2 seconds after but that causes other issues.
- (void)scrollViewDidScroll:(UIScrollView *)scrollView
{
moveFactor = 0 - (((self.scrollView.contentSize.height - self.scrollView.frame.size.height) - self.scrollView.contentOffset.y) / itemScrollViewMoveFactor);
[self updateLabelPositionScale];
}
- (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView
{
[self startDisplayLinkIfNeeded];
}
- (void)snapToItem
{
NSLog(@"%d", self.selectItem);
[self.scrollView setContentOffset:CGPointMake(0, (self.scrollView.contentSize.height - self.scrollView.frame.size.height) - (itemScrollViewHeight * self.selectItem)) animated:YES];
//[NSTimer scheduledTimerWithTimeInterval:2.0 target:self selector:@selector(stopDisplayLink) userInfo:nil repeats:NO];
[self stopDisplayLink];
}
- (void)scrollViewDidEndDragging:(UIScrollView *)scrollView willDecelerate:(BOOL)decelerate
{
if (!decelerate)
{
[self snapToItem];
}
}
- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView
{
[self snapToItem];
}
#pragma mark Display Link
- (void)startDisplayLinkIfNeeded
{
if (!self.displayLink)
{
self.displayLink = [CADisplayLink displayLinkWithTarget:self.view selector:@selector(display)];
[self.displayLink addToRunLoop:[NSRunLoop mainRunLoop] forMode:UITrackingRunLoopMode];
}
}
- (void)stopDisplayLink
{
if (self.displayLink)
{
[self.displayLink invalidate];
self.displayLink = nil;
}
}
