Can you attach a UIGestureRecognizer to multiple v

Question

UITapGestureRecognizer *tapGesture = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(tapTapTap:)];
[self.view1 addGestureRecognizer:tapGesture];
[self.view2 addGestureRecognizer:tapGesture];
[tapGesture release];

In the above code only taps on view2 are recognized. If I comment out the third line then taps on view1 are recognized. If I'm right and you can only use a gesture recognizer once, I'm not sure if this is a bug or it just needs some more documentation.

Answer 1

No you should not attach gesture recognizers to more than one view.

There is this explicit information in the Apple documentation:

Gesture Recognizers Are Attached to a View

Every gesture recognizer is associated with one view. By contrast, a view can have multiple gesture recognizers, because a single view might respond to many different gestures. For a gesture recognizer to recognize touches that occur in a particular view, you must attach the gesture recognizer to that view.

Event Handling Guide for iOS - Gesture Recognizers Apple Developer Library

While as others mention they might work in some cases it is clearly against the documentation and could change in any future iOS version.

What you can do is add separate gesture recognisers to the views you want to monitor and they can share a common action.

Answer 2

What about re write (recreate) your GestureRecognize every time that you add a gesture recognizer pointing to the same func. In below case it works. I am using IBOutletCollection

Swift 2:

@IBOutlet var topicView: [UIView]!

override func viewDidLoad() {
        for view in self.topicView as [UIView] {
        view.addGestureRecognizer(UITapGestureRecognizer(target: self, action: "viewClicked:"))
    }
}

func viewClicked(recognizer: UITapGestureRecognizer) {
    print("tap")
}

Answer 3

Override class by '<UIScrollViewDelegate>'

And use this method in .m class:

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer{
    return YES;
}

This method will help you to enable multiple swipe on a single view..

Answer 4

You can do it using this code my views which are imageviews in the xib.

- (void)viewDidLoad
{
    firstIV.tag = 501;
    secondIV.tag = 502;
    thirdIV.tag = 503;
    forthIV.tag = 504;

    [self addTapGesturetoImageView: firstIV];
    [self addTapGesturetoImageView: secondIV];
    [self addTapGesturetoImageView: thirdIV];
    [self addTapGesturetoImageView: forthIV];
}

-(void)addTapGesturetoImageView:(UIImageView*)iv
{
    iv.userInteractionEnabled = YES;
    UITapGestureRecognizer * textfielBGIVTapGasture = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(textfielBGIVTapped:)];
    textfielBGIVTapGasture.numberOfTapsRequired = 1;
    [iv addGestureRecognizer:textfielBGIVTapGasture];
}

- (void)textfielBGIVTapped:(UITapGestureRecognizer *)recognizer {
    int tag = recognizer.view.tag-500;
    switch (tag) {
        case 1:
        {
            //firstIV tapped;
            break;
        }
        case 2:
        {
            //secondIV tapped;
            break;
        }
        case 3:
        {
            //thirdIV tapped;
            break;
        }
        case 4:
        {
            //forthIV tapped;
            break;
        }
        default: {
            break;
        }
    }
}