Question

I have a view that is slightly translucent, I set the alpha to about .75 and it contains a button as a sub element.
I want the button to be completely opaque and I set the opaque property in IB but still the button appears as translucent.

Any pointers?

Thanks!

Answer 1

A subview of a superview is allways minimum as transparent as its subview.

Subview alpha = 0.5 and superview alpha = 0.1 would result in an alpha of the subview of 0.05.

The only way of achieving that is changing the view hierarchy. Your subview must not be a subview any more. It may still be at the same position. (May require different position value).

An example.
Your background view is backgroundView
Your superview is firstView
Your subview is overlayView

Your current hierarchy is

backgroundView -> firstView -> overlayView

You should change that to:

backgroundView -> first View
              \-> overlay View. 

If your firstView’s position is (10, 10) and your overlayView’s position was (20,20) then change your overlayView’s position to (30,30) because it now is within the coordinate system of background view.

For your code:
At some point you used to have

[backgroundView addSubView:firstView];
[fisrtView addSubView:overlayView];

change that to

[backgroundView addSubView:firstView];
[backgroundView addSubView:overlayView];

If you did not code that but defined it within IB then just move overlayView within the views tree accordingly so that it is on the same level as firstView.

Regardless whether you code it or draw it in IB, make sure that firstView comes first and overlayView comes next. Otherwise firstView could hide overlayView when its alpa is greater than 0.