Gesture recognizer and button actions

Mustafa picture Mustafa · Jan 28, 2011 · Viewed 82.1k times · Source

I have a view hierarchy that looks something like this:

UIView (A)
UIView > UIImageView
UIView > UIView (B)
UIView > UIView (B) > Rounded Rect Button
UIView > UIView (B) > UIImageView
UIView > UIView (B) > UILabel

I've attached gesture recognizer(s) to my UIView (B). The problem that i'm facing is that i don't get any actions for the Rounded Rect Button which is inside the UIView (B). The singleTap gesture recognizer captures/overrides the button's Touch Up Inside event.

How can i make it work? I thought that the responder chain hierarchy will make sure that the button touch event will be given preference, and it WILL get triggered! What am i missing?

Here's some related code:

#pragma mark -
#pragma mark View lifecycle (Gesture recognizer setup)

- (void)viewDidLoad {
    [super viewDidLoad];

    // double tap gesture recognizer
    UITapGestureRecognizer *dtapGestureRecognize = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(doubleTapGestureRecognizer:)];
    dtapGestureRecognize.delegate = self;
    dtapGestureRecognize.numberOfTapsRequired = 2;
    [self.viewB addGestureRecognizer:dtapGestureRecognize];

    // single tap gesture recognizer
    UITapGestureRecognizer *tapGestureRecognize = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(singleTapGestureRecognizer:)];
    tapGestureRecognize.delegate = self;
    tapGestureRecognize.numberOfTapsRequired = 1;
    [tapGestureRecognize requireGestureRecognizerToFail:dtapGestureRecognize];
    [self.viewB addGestureRecognizer:tapGestureRecognize];

    // add gesture recodgnizer to the grid view to start the edit mode
    UILongPressGestureRecognizer *pahGestureRecognizer = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(longPressGestureRecognizerStateChanged:)];
    pahGestureRecognizer.delegate = self;
    pahGestureRecognizer.minimumPressDuration = 0.5;
    [self.viewB addGestureRecognizer:pahGestureRecognizer];

    [dtapGestureRecognize release];
    [tapGestureRecognize release];
    [pahGestureRecognizer release];
}

#pragma mark -
#pragma mark Button actions

- (IBAction)buttonTouchUpInside:(id)sender {
    NSLog(@"%s, %@", __FUNCTION__, sender);
}

#pragma mark -
#pragma mark Gesture recognizer actions


- (void)singleTapGestureRecognizer:(UIGestureRecognizer *)gestureRecognizer {
    NSLog(@"%s", __FUNCTION__);
}

- (void)doubleTapGestureRecognizer:(UIGestureRecognizer *)gestureRecognizer {
    NSLog(@"%s", __FUNCTION__);
}

- (void)longPressGestureRecognizerStateChanged:(UIGestureRecognizer *)gestureRecognizer {

    switch (gestureRecognizer.state) {

        case UIGestureRecognizerStateEnded: {
            NSLog(@"%s", __FUNCTION__);

            break;
        }
        default:
            break;
    }
}

Answer

shannoga picture shannoga · Jan 28, 2011

In the "shouldReceiveTouch" method you should add a condition that will return NO if the touch is in the button.

This is from apple SimpleGestureRecognizers example.

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch {

    // Disallow recognition of tap gestures in the segmented control.
    if ((touch.view == yourButton)) {//change it to your condition
        return NO;
    }
    return YES;
}

hope it will help

Edit

As Daniel noted you must conform to UIGestureRecognizerDelegate for it to work.

shani