Some Cocoa and Cocoa Touch classes declare their delegate properties as assign
rather than weak
, which forces users of the class to nil
out the property in dealloc
-(void)dealloc
{
self.imageScrollView.delegate = nil;
self.tableView.delegate = nil;
self.tableView.dataSource = nil;
}
Which is very cumbersome.
Why would Apple do it this way?
The reason why is that not all system classes have been compiled with ARC.
You may implement a dealloc method if you need to manage resources
other than releasing instance variables. You do not have to (indeed
you cannot) release instance variables, but you may need to invoke
[systemClassInstance setDelegate:nil] on system classes and other code
that isn’t compiled using ARC.
See this page on developer.apple.com: Transitioning to ARC Release Notes