iOS x coordinate of finger when tapping on UIButton

Question

I have a UIButton. How can I get the x-coordinate of the finger when the user taps on said button. I'm thinking it will involve touchesBegan but how do I only get the value if the "touchesBegan" occurred on the button? And if there is a way (without just monitoring the x, y, width, and height of the button and checking if my touch was in that region) will I need to disable the button's user interaction so the code can handle it and not the built in xib stuff. Thanks!

Answer 1

A “tap” is generally considered to be a touch-down inside the button followed by a touch-up inside the button. You need to figure out whether you want the touch-down-inside event or the touch-up-inside event (or both).

Let's say you want the touch-down-inside event. Write a method like this in your view controller:

- (IBAction)buttonWasTouched:(UIButton *)button forEvent:(UIEvent *)event {
    NSSet *touches = [event touchesForView:button];
    NSLog(@"button:%@ touches:%@", button, touches);
}

If you're creating the button in a nib, control-click the button and connect its “Touch Down” outlet to the buttonWasTouched:forEvent: action on your view controller (which is probably File's Owner).

If you're creating the button in code, send an addTarget:action:forControlEvents: to the button to connect its UIControlEventTouchDown event to the view controller's buttonWasTouched:forEvent: action.

If you want to catch the touch-up-inside event, connect its “Touch Up Inside” outlet in the nib, or use UIControlEventTouchUpInside in code.