UIScrollView notifications

I'm coding an app that works much like Apple's Weather.app: There's a UIPageControl at the bottom and a UIScrollView in the middle of the screen. In my code, I implemented the - (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView method to figure out when the user did move to a new page. If they move to a new page, I load the adjacent pages' data, as to make further page-switching faster. (In one of Apple's examples, the - (void)scrollViewDidScroll:(UIScrollView *)sender is used, but that causes my app to shortly hang when loading a new page, so it's not suitable.) That code works very well.

I'm using scrollRectToVisible:: to programmatically scroll inside the scrollview when the user clicks the UIPageControl. The problem is that the scrollRectToVisible: doesn't post a notification to the UIScrollViewDelegate when it's done scrolling - so the code responsible for loading adjacent pages 开发者_JAVA技巧never get's called when using the UIPageControl.

Is there any way to make the UIScrollView notify its delegate when it gets called by the scrollRectToVisible: method? Or will I have to use threads in order to prevent my app from freezing?

Thanks!

-- Ry

How about -scrollViewDidEndScrollingAnimation:?

If it doesn't work, try to listen to the UITextSelectionDidScroll notification. (Of course, it's undocumented.)

Alternatively, an SDK-safe method is measure the time taken for the animation and send a delayed notification at the call site of -scrollRectToVisible:.

You could add this delegate method instead:

- (void)scrollViewDidEndScrollingAnimation:(UIScrollView *)scrollView

The scroll view calls this method at the end of its implementations of the UIScrollView and setContentOffset:animated: and scrollRectToVisible:animated: methods, but only if animations are requested.