Cocoa Outlets acting wierd, won't recognize selector - objective-c

Question

I'm getting some weird behavior, I Set a Label in Interface Builder, then I connect the label to a file as an Referencing Outlet.
#property (weak) IBOutlet NSTextField *TitleLabel;
When I access that label in the file (cell.TitleLabel.stringValue = title) and run the application, it doesn't recognize it.I get this:
-[NSApplication TitleLabel]: unrecognized selector sent to instance 0x608000101680
The weird thing is that it doesn't always do this, sometimes it works and displays correctly, other times it doesn't.
I've just started messing with IB so I'm probably missing something. Any help?

Answer 1

Is the property really on your NSApplication subclass? or is it on you application delegate class? It's not impossible for it to be on the application object, but it would be a pretty uncommon (and arguably ill-advised) pattern.
In short, I suspect you're probably connecting it to the wrong object.
EDIT: Ah. I see. You're trying to access things via the topLevelObjects array, but in practice, you can't count on the order of topLevelObjects. What you need to rely on the owner's outlets getting populated, but you're passing nil for the owner. topLevelObjects only exists to give the caller "ownership" (in the reference counting sense) of the top level objects in the xib for memory-mangement purposes, it's not really meant to be "used" directly like you're doing here. (In fairness, I can imagine situations where you might need to introspect that array, but this hardly rises to that level.)
The canonical way to do this would be to use an NSViewController subclass as the owner. In Xcode, if you add a subclass of NSViewController to your project, it will give you the option to create a xib file at the same time that will have everything hooked up. Then you just initialize the NSViewController subclass at runtime and the view outlet property of that class will be filled with the root view. You can obviously add more outlets and plug in whatever you like.
This post appears to cover the basics, if your looking for more details. Apple's docs on xib files and how they work are here.

Answer 2

The problem was that the View would sometimes get assigned to NSApplication. I'm not sure if the way that I am initiating the view is the common way of doing it but the problem was within this block of code:
NSArray * views;
[[NSBundle mainBundle] loadNibNamed:#"CollapseClickViewController" owner:nil topLevelObjects:&views];
CollapseClickCell * cell = [[CollapseClickCell alloc] initWithFrame:CGRectMake(0,0,320,50)];
cell = [views objectAtIndex:0];
the problem was that [views objectAtIndex:0] would sometimes return NSApplication. To fix it I just checked the class against itself and returned that object via:
-(CollapseClickCell*)assignCell:(CollapseClickCell*)cell withArray:(NSArray*)array{
for ( int i = 0; i< [array count]; i++) {
if ([[array objectAtIndex:i] class] == [CollapseClickCell class]) {
return [array objectAtIndex:i];
}
}
return nil;
}
I then assign that to the object:
cell = [cell assignCell:cell withArray:views];
It may not be the conventional way of doing it but it works. If there is a better technique or a more common approach please enlighten me! :)