Question

I have an app with two windows – a main window, and a preferences window which can be opened from the menubar. I am trying to implement a notification that the preferences window becomes the main window so that I can update it when it is opened, however my notificaton is firing whenever any window opens, even a different window.

inside my PrefsWindowViewController.m awakeFromNib I have:

[[NSNotificationCenter defaultCenter] addObserver:self
                                         selector:@selector(didBecomeMain:)
                                             name:NSWindowDidBecomeMainNotification
                                           object:nil];

And in my PrefsWindowViewController.m dealloc, I have:

[[NSNotificationCenter defaultCenter] removeObserver:self name: NSWindowDidBecomeMainNotification object:nil];

Can anybody explain why this might get called when a different window besides my PrefsWindow becomes the main window?

Answer 1

It’s because you’re passing nil for the object: parameter. Pass your preferences window instead, or check [notification object] == yourPrefsWindow in your callback.