lua - How to give priority to button

Question

I have 2 buttons, one of which is on top of another. Screenshot: http://prntscr.com/akc6f7 (2 buttons)

Basically, when I click on smaller button in the corner ("?"), I also click on the bigger. How can I make sure that I only click "?" button?

Also, those buttons are newImageRect().

Answer 1

Touch events will fire on the outer most UI element first.

Add return true to the end of "?" button touch event to signal that the touch has been handled by the code.

Without the return true, the touch event does not know it is handled and subsequently fires on all elements that contain the touch (giving priority to elements outermost elements)

function QuestionMarkTouchEvent( event )

if event.phase == "began" then 
    -- Do some stuff
end

return true  -- this tells the program not to fire the touch event again on elements under this.

end