iphone - single tap gesture conflicts with double one

I have a view. I wish to define to kinds of tap gestures for it.

So if a user single tap on the view, view will do A; and if a user double tap on the view, it will do B without doing A.

I added two UITapGestureRecognizer to the view. the single tap is with numberOfTapsRequired = 1; and the double tap is with numberOfTapsRequired = 2;

Also I set return NO for

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer {
     return NO;
}

However, I found that they conflict with each other. I mean, even if I double tap on the view, both A and B will be invoked.

How can I solve this pro开发者_开发问答blem?

Thanks

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You can work around this by adding the following line of code. This will make sure that the single tap recognizer only fires when the double tap recognizer failed:

    [singleTapRecognizer requireGestureRecognizerToFail:doubleTapRecognizer];