Question

Basicly I’m making an image gallery that downloads from the web.

So – when the user scrolls, a new image downloads.

Keep in mind that the code is very simplyfied, just to show you what I mean

-(void)scrollViewDidScroll:(UIScrollView *)scrollView
{
        // If new page then:
        [self loadNextPicture];
}

-(void)loadNextPicture
{
   NSString *url=@"http://www.example.com/image.png";
        NSURL *imageURL = [NSURL URLWithString:url];
        NSData *imageData = [NSData dataWithContentsOfURL:imageURL];
        UIImage *nextImage = [UIImage imageWithData:imageData];
        myUIImageView.image=nextImage;

}

My problem is that every time a user scrolls to a new page, the application freezes for about a second while it downloads the image. Is there a way I can download it in the background so that the app won’t freeze while downloading?

Appriciate every thoughts on this matter.

Andreas 🙂

Answer 1

[self performSelectorInBackground:@selector(loadNextPicture) withObject:nil];

NSObject Class Reference