My iOS app freezes but no error appears

freeze, ios, ipad, iphone, multithreading

Solution

Generally, it is highly recommended to perform on the main thread all animations method and interface manipulation, and to put in background tasks like download data from your server, etc...

dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_DEFAULT, 0), ^{
    //here everything you want to perform in background

    dispatch_async(dispatch_get_main_queue(), ^{ 
        //call back to main queue to update user interface
    });
});

Source : http://www.raywenderlich.com/31166/25-ios-app-performance-tips-tricks

Problem

Does any body know what I need to check if app freezes after some time? I mean, I can see the app in the iPhone screen but no view responds. I did some google and i found that, i've blocked the main thread somehow. But my question is how to identify which method causes blocking of main thread? is there any way to identify?

Original source