setNeedsLayout and setNeedsDisplay

Actually the documentation is pretty clear about this: setNeedsLayout will layout subviews Call this method on your application’s main thread when you want to adjust the layout of a view’s subviews. setNeedsDisplay will call for a redraw of your view (drawRect:, etc). You can use this method or the setNeedsDisplayInRect: to notify the system that … Read more