Question

In my app, I use a scroll view in which I display 300 image (400 kB).
It takes nearly 2 minutes, and as a result, when I scroll up and down, it isn’t smooth.

How can I solve this problem?

Note: I have noticed that after I scroll down to end of scrollview once, it gets smooth.
The issue with scrolling only appears the first time.

Answer 1

Try adding this in your load function (where you load your images). If you are using a while or for loop to load images, add this code to the loop.

NSURL *url=//here url for your image   
dispatch_queue_t currentQueue = dispatch_get_current_queue();
dispatch_queue_t dataConvertorQueue = dispatch_queue_create("Fetching images", NULL);
dispatch_async(dataConvertorQueue, ^{
    NSData *data = [NSData dataWithContentsOfURL:url];
    dispatch_async(currentQueue, ^{
       //replace imageView with your imageView outlet
       imageView.image = [[UIImage alloc] initWithData:data]];
    });
});
dispatch_release(dataConvertorQueue);

This code helps you fetch and show images from a url and it works great with a tableview. It might not be exactly what you want but it’ll give you an idea on how to do it. Hope it’ll help you.