Iphone – single tap gesture conflicts with double one

iphonetapuigesturerecognizer

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 problem?

Thanks

Best Answer

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];

Related Solutions

Ios – UITableview didSelectRowAtIndexPath supercedes double tap gesture by UITapGestureRecognizer

More info about Kris' answer:

cancelsTouchesInView
delaysTouchesBegan
delaysTouchesEnded

http://developer.apple.com/library/ios/#documentation/uikit/reference/UIGestureRecognizer_Class/Reference/Reference.html

In my case I had a problem when adding 2 tap gestures to a UIImageView that was on a custom UITableViewCell. What happened was the didSelectRowAtIndexPath: was called when you tap/double tap on the UIImageView. When I had only one tap gesture, the didSelectRowAtIndexPath: was not called (and for me, that was the right behavior.

To prevent the didSelectRowAtIndexPath: from being called when using two tap gestures (single/double tap), I added this code to the first tap gesture (the single one):

tapGesture.cancelsTouchesInView = YES;
tapGesture.delaysTouchesBegan = YES;

After this change, a tap/double on the UIImageView (on top of the custom cell) did not trigger the didSelectRowAtIndexPath:

Ios – UITapGestureRecognizer – single tap and double tap

UITapGestureRecognizer *singleTap = [[[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(doSingleTap)] autorelease];
singleTap.numberOfTapsRequired = 1; 
[self.view addGestureRecognizer:singleTap];

UITapGestureRecognizer *doubleTap = [[[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(doDoubleTap)] autorelease];
doubleTap.numberOfTapsRequired = 2; 
[self.view addGestureRecognizer:doubleTap];

[singleTap requireGestureRecognizerToFail:doubleTap];

Note: If you are using numberOfTouchesRequired it has to be .numberOfTouchesRequired = 1;

For Swift

let singleTapGesture = UITapGestureRecognizer(target: self, action: #selector(didPressPartButton))
singleTapGesture.numberOfTapsRequired = 1
view.addGestureRecognizer(singleTapGesture)

let doubleTapGesture = UITapGestureRecognizer(target: self, action: #selector(didDoubleTap))
doubleTapGesture.numberOfTapsRequired = 2
view.addGestureRecognizer(doubleTapGesture)

singleTapGesture.require(toFail: doubleTapGesture)

Best Answer

Related Solutions

Ios – UITableview didSelectRowAtIndexPath supercedes double tap gesture by UITapGestureRecognizer

Ios – UITapGestureRecognizer – single tap and double tap

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