Question

Playing around in Instruments, I noticed something I don’t understand. I create a couple of UIViewControllers and add their views to another UIView:

CustomVC *vc = [[CustomVC alloc] initWithCustomInitializer:someParameter];
[mainView addSubview:vc.view];

By logging the memory address of the CustomVC in its init and dealloc, I see that vc is deallocated almost immediately, though the view remains on screen and everything works fine.

Does the UIView not necessarily need its controller? Or is something else going on that I’m misinterpreting?

Answer 1

A UIView doesn’t/shouldn’t retain its parent (the UIViewController), so if you drop your reference to the UIViewController and only keep the reference to the UIView, nothing keeps a strong reference to it and it will be released.

The weak reference in the UIView to its controller will be automatically set to nil.

Whether the UIView needs its “lost” controller to do its work is another story though, and entirely depending on the UIView.