I have a button which when pressed makes calls that load information from a series of URLs (about 5 seconds loading time). Right before actually making those calls I want to add
when you try to retrieve data from the internet (I guess you are using something like [NSString stringWithContentsOfURL: ...]) the main thread is waiting for those data and for this reason the application cannot redraw the interface. You can try to use:
[mySourceData performSelectorInBackground:@selector(loadData) withObject:nil];
Be careful if you are using coredata to lock the NSManagedObjectContext before doing any operation on it and unlock it when you finish.