How to read size of UISlider thumb image

Question

I\'m trying to position an additional UIView centered above the thumb in a UISlider. To do this, I need the width of the thumb image. In iOS6, this works fine. I can use:

Answer 1

I believe this will sometimes return 0, if the layout flow hasn't completed. I had some trouble with it.

CGRect thumbRect = [self thumbRectForBounds:self.bounds
                                  trackRect:[self trackRectForBounds:self.bounds]
                                      value:self.value];
CGFloat thumbDiameter = CGRectGetHeight(thumbRect);