case sensitivity matters, b.t.w.
change that to:
[self.view setNeedsDisplay];
And as you've discovered, you call "setNeedsDisplay
" on the UIView object, not the UIViewController (which is the "No visible @interface for viewcontroller declares the selector 'setNeedsDisplay'
" error you were seeing).
The place where "setNeedsDisplay:
" takes a YES or NO parameter is on the Macintosh side, in NSView.