iPhone: How to avoid background color coming up when button is selected?

I have a button with a curved image set as its foreground image. It looks like:

Now when the button is on pressed state, it shows up like this:

notice the grey rectangular color coming up around the edges. Is there any easy way to avoid the grey 开发者_StackOverflowbackground coming all over the rectangle ?

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You need to set the property Shows Touch On Highlight to enabled.

Programmatically you can do that with:

[button setShowsTouchWhenHighlighted:YES];