By ThomasM


2011-03-25 13:21:28 8 Comments

Is it possible for a UIButton (or any other control for that matter) to receive touch events when the UIButton's frame lies outside of it's parent's frame? Cause when I try this, my UIButton doesn't seem to be able to receive any events. How do I work around this?

8 comments

@Ankit Kushwah 2018-09-26 07:26:30

swift 4.1 updated

To get touch events in same UIView you just need to add following override method, it will identify specific view tapped in UIView which is placed out of bound

override func hitTest(_ point: CGPoint, with event: UIEvent?) -> UIView? {
    let pointforTargetview:CGPoint = self.convert(point, to: btnAngle)
    if  btnAngle.bounds.contains(pointforTargetview) {
        return  self
    }
    return super.hitTest(point, with: event)
}

@Scott Zhu 2018-01-10 22:46:33

Why this is happening?

This is because when your subview lies outside of your superview's bounds, touch events that actually happens on that subview will not be delivered to that subview. However, it WILL be delivered to its superview.

Regardless of whether or not subviews are clipped visually, touch events always respect the bounds rectangle of the target view’s superview. In other words, touch events occurring in a part of a view that lies outside of its superview’s bounds rectangle are not delivered to that view. Link

What you need to do?

When your superview receives the touch event mentioned above, you'll need to tell UIKit explicitly that my subview should be the one to receive this touch event.

What about the code?

In your superview, implement func hitTest(_ point: CGPoint, with event: UIEvent?)

override func hitTest(_ point: CGPoint, with event: UIEvent?) -> UIView? {
        if isHidden || alpha == 0 || clipsToBounds { return nil }
        // convert the point into subview's coordinate system
        let subviewPoint = self.convert(point, to: subview)
        // if the converted point lies in subview's bound, tell UIKit that subview should be the one that receives this event
        if ! subview.isHidden && subview.bounds.contains(subviewPoint) { return subview }
        return nil
    }

@ClayJ 2018-02-24 00:58:23

Thank you for this! I have spent hours and hours on an issue stemming from this. I really appreciate your taking the time to post this. :)

@Dan Rosenstark 2017-01-09 15:13:37

For me (as for others), the answer was not to override the hitTest method, but rather the pointInside method. I had to do this in only two places.

The Superview This is the view that if it had clipsToBounds set to true, it would make this whole problem disappear. So here's my simple UIView in Swift 3:

class PromiscuousView : UIView {
    override func point(inside point: CGPoint,
               with event: UIEvent?) -> Bool {
        return true
    }
} 

The Subview Your mileage may vary, but in my case I also had to overwrite the pointInside method for the subview that was had decided the touch was out of bounds. Mine is in Objective-C, so:

- (BOOL)pointInside:(CGPoint)point withEvent:(UIEvent *)event {
    WEPopoverController *controller = (id) self.delegate;
    if (self.takeHitsOutside) {
        return YES;
    } else {
        return [super pointInside:point withEvent:event];
    }
}

This answer (and a few others on the same question) can help clear up your understanding.

@user3344977 2015-11-30 23:29:56

In my case, I had a UICollectionViewCell subclass that contained a UIButton. I disabled clipsToBounds on the cell and the button was visible outside of the cell's bounds. However, the button was not receiving touch events. I was able to detect the touch events on the button by using Jack's answer: https://stackoverflow.com/a/30431157/3344977

Here's a Swift version:

override func hitTest(point: CGPoint, withEvent event: UIEvent?) -> UIView? {

    let translatedPoint = button.convertPoint(point, fromView: self)

    if (CGRectContainsPoint(button.bounds, translatedPoint)) {
        print("Your button was pressed")
        return button.hitTest(translatedPoint, withEvent: event)
    }
    return super.hitTest(point, withEvent: event)
}

@Ja͢ck 2015-05-25 04:17:23

In the parent view you can override the hit test method:

- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event
{
    CGPoint translatedPoint = [_myButton convertPoint:point fromView:self];

    if (CGRectContainsPoint(_myButton.bounds, translatedPoint)) {
        return [_myButton hitTest:translatedPoint withEvent:event];
    }
    return [super hitTest:point withEvent:event];

}

In this case, if the point falls within the bounds of your button, you forward the call there; if not, revert to the original implementation.

@Luke Bartolomeo 2015-04-25 19:26:27

Swift:

Where targetView is the view you wish to receive the event (which may be entirely or partially located outside of the frame of its parent view).

override func hitTest(point: CGPoint, withEvent event: UIEvent?) -> UIView? {
        let pointForTargetView: CGPoint = targetView.convertPoint(point, fromView: self)
        if CGRectContainsPoint(targetView.bounds, pointForTargetView) {
            return closeButton
        }
        return super.hitTest(point, withEvent: event)
}

@jnic 2011-03-25 13:36:21

Yes. You can override the hitTest:withEvent: method to return a view for a larger set of points than that view contains. See the UIView Class Reference.

Edit: Example:

- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *)event
{
    CGFloat radius = 100.0;
    CGRect frame = CGRectMake(-radius, -radius,
                              self.frame.size.width + radius,
                              self.frame.size.height + radius);

    if (CGRectContainsPoint(frame, point)) {
        return self;
    }
    return nil;
}

Edit 2: (After clarification:) In order to ensure that the button is treated as being within the parent's bounds, you need to override pointInside:withEvent: in the parent to include the button's frame.

- (BOOL)pointInside:(CGPoint)point withEvent:(UIEvent *)event
{
    if (CGRectContainsPoint(self.view.bounds, point) ||
        CGRectContainsPoint(button.view.frame, point))
    {
        return YES;
    }
    return NO;
}

Note the code just there for overriding pointInside is not quite correct. As Summon explains below, do this:

-(BOOL)pointInside:(CGPoint)point withEvent:(UIEvent *)event
    {
    if ( CGRectContainsPoint(self.oversizeButton.frame, point) )
        return YES;

    return [super pointInside:point withEvent:event];
    }

Note that you'd very likely do it with self.oversizeButton as an IBOutlet in this UIView subclass; then you can just drag the "oversize button" in question, to, the special view in question. (Or, if for some reason you were doing this a lot in a project, you'd have a special UIButton subclass, and you could look through your subview list for those classes.) Hope it helps.

@ThomasM 2011-03-25 13:42:55

Can you help me further on implementing this correctly with some sample code? Also I read the reference and because of the following line, I'm confused: "Points that lie outside the receiver’s bounds are never reported as hits, even if they actually lie within one of the receiver’s subviews. Subviews may extend visually beyond the bounds of their parent if the parent view’s clipsToBounds property is set to NO. However, hit testing always ignores points outside of the parent view’s bounds."

@ThomasM 2011-03-25 13:52:12

It's especially this part that makes it seem as if this is not the solution I need: "However, hit testing always ignores points outside of the parent view’s bounds".. But I could be wrong ofcourse, I find the apple references sometimes really confusing..

@jnic 2011-03-25 14:58:50

Ah, I understand now. You need to override the parent's pointInside:withEvent: to include the frame of the button. I will add some sample code to my answer above.

@RLH 2012-04-04 16:15:21

Is there a way of doing this without overriding methods of a UIView? For instance, if your views are entirely generic to UIKit and initialized via a Nib, can you override these methods from within your UIViewController?

@jnic 2012-04-05 14:23:09

You can't override the methods directly; however, you could override touchesBegan etc. as UIViewController is a UIResponder subclass. Views initialized directly from nibs can still be custom subclasses. Just set the Class field of your view in the Identity Inspector to be your custom subclass and, after loading, cast your nib accordingly.

@Jeremy Wiebe 2013-11-01 15:47:02

One other note about this solution. In hitTest:withEvent: you should return the lowest descendant that matches the hit test. What this means is that if you have a button outside the bounds of the parent view, you would hitTest that button first and return it, then just call 'return [super hitTest:point withEvent:event];'

@rob5408 2014-07-01 01:08:27

Shouldn't the frame tested in the first block be CGRectMake(-radius, -radius, self.frame.size.width + 2 * radius, self.frame.size.height + 2 * radius)? Otherwise the overflow on the right and bottom edge is flush with the original right and bottom.

@Iulian Onofrei 2015-02-27 12:15:36

The method is not called.

@Jorge Wander Santana Ureña 2016-07-05 16:33:05

Thanks, this put me in the right way to go. i override pointInside of my button parent view to return true (on custom frame size) and that made all the work.

@iosdude 2017-06-13 07:45:03

hitTest:withEvent: and pointInside:withEvent: area not called for me when I press on a button that lies outside of parent's bounds. What can be wrong?

@Summon 2012-02-02 14:22:55

@jnic, I am working on iOS SDK 5.0 and in order to get your code working right I had to do this:

- (BOOL)pointInside:(CGPoint)point withEvent:(UIEvent *)event {
if (CGRectContainsPoint(button.frame, point)) {
    return YES;
}
return [super pointInside:point withEvent:event]; }

The container view in my case is a UIButton and all the child elements are also UIButtons that can move outside the bounds of the parent UIButton.

Best

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