Question:

I have defined a custom class with a drawRect called Drawing. I have laid out the view in my NIB to contain an NSScrollView with a Drawing subview. When I launch the program, the screen is blank. Interestingly, when I create the documentView for the NSScrollView programmatically, I get an image in my scroll view. When I use the instance for the nib in my setDocumentView, I get nothing.

So if the Drawing view is set in IB,

[_scrollViewWorkspace setDocumentView:_drawing]; //does not work.

But

[_scrollViewWorkspace setDocumentView:[[Drawing alloc] initWithFrame:NSMakeRect(0,0,[[_scrollViewWorkspace documentView ]bounds].size.width, [[_scrollViewWorkspace documentView] bounds ].size.height)]];

Works great!

Why can't I statically bind a drawing object in a NIB?

When you set the custom class of the NSView subclass in the nib file to your custom class, at runtime, an instance of that class will be created using initWithCoder: rather than initWithFrame:.

You can easily check to see if this is the case by adding the following method to your custom Drawing view:

- (id)initWithCoder:(NSCoder *)coder { NSLog(@"[%@ %@]", NSStringFromClass([self class]), NSStringFromSelector(_cmd)); return [super initWithCoder:coder]; }

Then launch your app and see if [Drawing initWithCoder:] is logged to the console.

If you have overridden initWithFrame: in your Drawing class to do custom initialization (like set a custom image automatically), you will need to add that same code to the initWithCoder: method so that you end up with the same result:

- (id)initWithCoder:(NSCoder *)coder { if ((self = [super initWithCoder:coder])) { // do custom initialization here } return self; }

Solved!

When I laid the view out in Interface Builder I just dragged the custom view to the NSScrollView in the canvas. I re-did the layout so that I used Embed->Scroll View and it worked.

Bruce