UITapGestureRecognizer tap on self.view but ignore subviews

Question

I need to implement a feature that will invoke some code when I double tap on the self.view (view of UIViewController). But the problem that I have other UI object on this view and I don't want to attach any recognizer object to all of them. I found this method below how to make gesture on my view and I know how it works. Right now I am in front of handicap which way to choose for create this recognizer ignoring subview. Any ideas? Thanks.

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

I'm not sure, but have you tried setting cancelsTouchesInView to NO on the recognizer? so [doubleTap setCancelsTouchesInView:NO]; — JDx, Apr 04 '13 at 15:00

score 181 · Accepted Answer · edited Mar 28 '20 at 21:11

181

You should adopt the UIGestureRecognizerDelegate protocol inside the self object and call the below method for checking the view. Inside this method, check your view against touch.view and return the appropriate bool (Yes/No). Something like this:

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch
{
    if ([touch.view isDescendantOfView:yourSubView]) {
        return NO;
    }
    return YES;
}

Edit: Please, also check @Ian's answer!

Swift 5

// MARK: UIGestureRecognizerDelegate methods, You need to set the delegate of the recognizer
func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldReceive touch: UITouch) -> Bool {
     if touch.view?.isDescendant(of: tableView) == true {
        return false
     }
     return true
}

edited Mar 28 '20 at 21:11

SwiftiSwift

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answered Apr 04 '13 at 14:59

Ravi

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one more question I have few buttons on my view that have to work. how can I set some priority for them? – Matrosov Oleksandr Apr 04 '13 at 15:16
if your buttons have their own gesture recognizers (likely), dig into their internals and grab them, and read the docs on `-[UIGestureRecognizer requireGestureRecognizerToFail:]` but it might work without mod'ing them – bshirley Apr 04 '13 at 15:56
If your `if` test fails, your implementation fails to return a BOOL; for proper style return YES after an if block (using `{ }`) or in an `else` branch. Thanks, though, saved me a bit of reading. – RobP Jun 13 '15 at 16:14
2

A view is a descendant of itself so this doesn't work... (the overall approach is ok though, see other answer) – User Sep 09 '17 at 19:21
why not just `return ![touch.view isDescendantOfView:yourSubView]` – d4Rk Mar 08 '18 at 10:55

score 129 · Answer 2 · edited Jan 23 '18 at 21:45

129

Another approach is to just compare if the view of the touch is the gestures view, because descendants won't pass the condition. A nice, simple one-liner:

func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldReceive touch: UITouch) -> Bool {
    return touch.view == gestureRecognizer.view
}

edited Jan 23 '18 at 21:45

Den

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answered Jul 06 '16 at 06:00

Ian

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This is working better for me than the accepted answer. Much more concise. – Suman Roy Jun 19 '17 at 07:43
1

@Ian this method is not invoked when tapping on the view. – Praburaj Sep 14 '17 at 12:05
1

The accepted answer didn't even work but this worked flawlessly for me. – Shalin Shah Sep 17 '18 at 19:25
1

@Prabu propably because gesture recognizer's delegate must be set before – Kubba Jan 17 '19 at 15:46
It the concerned subview has a child view, that child view's isUserInteractionEnabled property should be set false. Otherwise tapping on the child view wont let the subview recognize touch. – Gaurav Bishnoi Nov 26 '20 at 10:49

score 24 · Answer 3 · answered Feb 28 '15 at 10:37

24

And for the Swift variant:

func gestureRecognizer(gestureRecognizer: UIGestureRecognizer, shouldReceiveTouch touch: UITouch) -> Bool {
    if touch.view.isDescendantOfView(yourSubView){
        return false
    }
    return true
}

Good to know, isDescendantOfView returns a Boolean value indicating whether the receiver is a subview of a given view or identical to that view.

answered Feb 28 '15 at 10:37

Antoine

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Don't forget to set the UIGestureRecognizerDelegate in your class ! – Fox5150 Aug 05 '16 at 13:32
4

Instead of doing that if statement, can't you just return this? return !touch.view.isDescendant(of: gestureRecognizer.view) Also, new syntax in swift 3 ^^ – EdwardSanchez May 13 '17 at 21:02

Imanou Petit · Answer 4 · 2019-07-07T10:30:18.287

With Swift 5 and iOS 12, UIGestureRecognizerDelegate has a method called gestureRecognizer(_:shouldReceive:). gestureRecognizer(_:shouldReceive:) has the following declaration:

Ask the delegate if a gesture recognizer should receive an object representing a touch.

optional func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldReceive touch: UITouch) -> Bool

The complete code below shows a possible implementation for gestureRecognizer(_:shouldReceive:). With this code, a tap on a subview of the ViewController's view (including imageView) won't trigger the printHello(_:) method.

import UIKit

class ViewController: UIViewController, UIGestureRecognizerDelegate {

    override func viewDidLoad() {
        super.viewDidLoad()

        let tapGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(printHello))
        tapGestureRecognizer.delegate = self
        view.addGestureRecognizer(tapGestureRecognizer)

        let imageView = UIImageView(image: UIImage(named: "icon")!)
        imageView.frame = CGRect(x: 50, y: 50, width: 100, height: 100)
        view.addSubview(imageView)

        // ⚠️ Enable user interaction for imageView so that it can participate to touch events.
        // Otherwise, taps on imageView will be forwarded to its superview and managed by it.
        imageView.isUserInteractionEnabled = true
    }

    func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldReceive touch: UITouch) -> Bool {
        // Prevent subviews of a specific view to send touch events to the view's gesture recognizers.
        if let touchedView = touch.view, let gestureView = gestureRecognizer.view, touchedView.isDescendant(of: gestureView), touchedView !== gestureView {
            return false
        }
        return true
    }

    @objc func printHello(_ sender: UITapGestureRecognizer) {
        print("Hello")
    }

}

An alternative implementation of gestureRecognizer(_:shouldReceive:) can be:

func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldReceive touch: UITouch) -> Bool {
    return gestureRecognizer.view === touch.view
}

Note however that this alternative code does not check if touch.view is a subview of gestureRecognizer.view.

score 10 · Answer 5 · answered Jul 28 '16 at 09:20

Complete swift solution (delegate must be implemented AND set for recognizer(s) ):

class MyViewController: UIViewController UIGestureRecognizerDelegate {

    override func viewDidLoad() {
        let doubleTapRecognizer = UITapGestureRecognizer(target: self, action: #selector(onBaseTapOnly))
        doubleTapRecognizer.numberOfTapsRequired = 2
        doubleTapRecognizer.delegate = self
        self.view.addGestureRecognizer(doubleTapRecognizer)
    }

    func gestureRecognizer(gestureRecognizer: UIGestureRecognizer, shouldReceiveTouch touch: UITouch) -> Bool {
        if touch.view.isDescendantOfView(self.view){
            return false
        }
        return true
    }

    func onBaseTapOnly(sender: UITapGestureRecognizer) {
        if sender.state == .Ended {
            //react to tap
        }
    }
}

score 7 · Answer 6 · answered May 14 '18 at 14:33

Variant using CGPoint you touch (SWIFT 4.0)

class MyViewController: UIViewController, UIGestureRecognizerDelegate {

  func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldReceive touch: UITouch) -> Bool {

// Get the location in CGPoint
    let location = touch.location(in: nil)

// Check if location is inside the view to avoid
    if viewToAvoid.frame.contains(location) {
        return false
    }

    return true
  }
}

score 5 · Answer 7 · answered Mar 31 '19 at 14:06

5

Clear Swift way

func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldReceive touch: UITouch) -> Bool {
    return touch.view == self.view
}

answered Mar 31 '19 at 14:06

Musa almatri

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Never gets called in iOS 13, at least with swipeGestureRecognizer. – Chewie The Chorkie Sep 19 '19 at 15:03
1

How is this different to Ian's answer? – sweetfa Mar 05 '20 at 08:16

Rico · Answer 8 · 2017-09-06T16:12:35.870

Note that the gestureRecognizer API has changed to:

gestureRecognizer(_:shouldReceive:)

Take particular note of the underscore (skip) indicator for the first parameter's external label.

Using many of the examples provided above, I was not receiving the event. Below is a an example that works for current versions of Swift (3+).

public func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldReceive touch: UITouch) -> Bool {
    var shouldReceive = false
    if let clickedView = touch.view {
        if clickedView == self.view {
            shouldReceive = true;
        }
    }
    return shouldReceive
}

score 2 · Answer 9 · answered Feb 25 '18 at 16:25

2

Plus the above solutions, do not forget to check User Interaction Enabled of your sub-view.

answered Feb 25 '18 at 16:25

MrDEV

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score 2 · Answer 10 · answered Mar 13 '19 at 15:17

I had to prevent the gesture on the child view. The only thing that worked is to allow and keep the first view and prevent gesture in all the next views:

   var gestureView: UIView? = nil

    func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldReceive touch: UITouch) -> Bool {
        if (gestureView == nil || gestureView == touch.view){
            gestureView = touch.view
            return true
        }
        return false
     }

score 1 · Answer 11 · answered Nov 07 '18 at 18:37

Swift 4:

touch.view is now an optional, so based on @Antoine's answer:

func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldReceive touch: UITouch) -> Bool {
    if let touchedView = touch.view, touchedView.isDescendant(of: deductibleBackgroundView) {
        return false
    }
    return true
}

score 1 · Answer 12 · answered Jul 01 '20 at 13:37

If you don't want your 'double-tap recogniser' to conflict with your buttons and/or other controls, you can set self as UIGestureRecognizerDelegate and implement:

func gestureRecognizer(_ gestureRecognizer: UIGestureRecognizer, shouldReceive touch: UITouch) -> Bool
{
    return !(touch.view is UIControl)
}

score 0 · Answer 13 · answered Nov 03 '22 at 15:41

Another solution may be found with the hitTest function, which

Returns the farthest descendant of the receiver in the view hierarchy (including itself) that contains a specified point.

By this way defining the UIGestureRecognizerDelegate is not necessary:

@objc func tapFunction (_ recognizer : UITapGestureRecognizer) {
    if let viewTouched = recognizer.view?.hitTest(recognizer.location(in: recognizer.view), with: nil) {
        if viewTouched == self.parentView {
            //the parent view is tapped!
        }
    }
}

UITapGestureRecognizer tap on self.view but ignore subviews

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