Question

I have main UIScrollView with lots off buttons which i create like this:

UIButton *myButton = [UIButton buttonWithType:UIButtonTypeCustom]

every button have an image:

UIImage *fileImage = [UIImage imageNamed:@"sun.png"];
[myButton setBackgroundImage:fileImage forState:UIControlStateNormal];

Buttons count could be more than 500. So i need to remove from UIscrollView invisible buttons with images to save memory ?

I believe in this method i need to calculate when UIscrollview is stopped scrolling and for example 20 images are invisible, then i need to remove them and reduce scroller contentOffset.

-(void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView {

    float bottomEdge = scrollView.contentOffset.y + scrollView.frame.size.height;
}

Maybe some one could give me tips on this. Or even have a good bookmarked tutorial.

Answer 1

I created a similar thing to this using UIViews in a UIScrollView. When the UIScrollView loads, I set the contentView size of the scrollView to be the size of all the views but only loaded the views that can be seen, then when the user scrolls i added the previous/next views and removed the hidden views.

This question helped me: How to implement UIScrollView with 1000+ subviews? especially akosma’s answer