UIScrollView touchesBegan

Question

So all I wanna do is play a sound when the user touches a UIScrollView. The UIScrollViewDelegate has that scrollViewWillBeginDragging: method but it only gets called on touchMoved. I want it to get called on touchBegan.

Tried touchesBegan:withEvent: but it doesn't receive any touch. Anyone has a clue?

score 18 · Answer 1 · answered Jul 20 '13 at 06:24

Use a Tap Gesture Recognizer instead:

UITapGestureRecognizer *recognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(touch)];
[recognizer setNumberOfTapsRequired:1];
[recognizer setNumberOfTouchesRequired:1];
[scrollView addGestureRecognizer:recognizer];

Or

make subClass of your UIScrollView and implement all

    -(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{

// If not dragging, send event to next responder
  if (!self.dragging){ 
    [self.nextResponder touchesBegan: touches withEvent:event]; 
  }
  else{
    [super touchesEnded: touches withEvent: event];
  }
}
-(void)touchesMoved:(NSSet *)touches withEvent:(UIEvent *)event{

// If not dragging, send event to next responder
    if (!self.dragging){ 
     [self.nextResponder touchesBegan: touches withEvent:event]; 
   }
   else{
     [super touchesEnded: touches withEvent: event];
   }
}
-(void)touchesEnded:(NSSet *)touches withEvent:(UIEvent *)event{

  // If not dragging, send event to next responder
   if (!self.dragging){ 
     [self.nextResponder touchesBegan: touches withEvent:event]; 
   }
   else{
     [super touchesEnded: touches withEvent: event];
   }
}

@Rajneesh071 where are you handling the boolean "dragging" ? is it automatically handled when subclassing `UIScorllView` ? — jeet.chanchawat, Feb 23 '15 at 06:45
@jeet.chanchawat Dude its subClass of your UIScrollView, and dragging is boolean property of UIScrollView — Rajneesh071, Mar 01 '15 at 09:12

score 13 · Answer 2 · answered Jan 15 '13 at 10:41

13

Use a Tap Gesture Recognizer instead:

UITapGestureRecognizer *recognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(touch)];
[recognizer setNumberOfTapsRequired:1];
[recognizer setNumberOfTouchesRequired:1];
[scrollView addGestureRecognizer:recognizer];

answered Jan 15 '13 at 10:41

Adam Ivancza

2,459
1
25
36

Ok, this Works, but How should I Declare the Method "touch" to Receive the Place where the User Touched? – Hernan Arber Aug 05 '14 at 11:45
@HernanArber For example: http://stackoverflow.com/questions/8721864/getting-screen-coordinates-from-uilongpressgesturerecognizer – Adam Ivancza Aug 05 '14 at 12:36

score 6 · Accepted Answer · answered Nov 06 '09 at 08:00

I think you will have to subclass UIScrollView to be able to do this.

touchesBegan:withEvent: is only sent to subclasses of UIView. You are problably implementing touchesBegan:withEvent: in your controller, right? If so, it won't work from there...

Alternatively, if you put a subclass of UIView (that you wrote) in your UIScrollView, you can also catch the touchesBegan event from there (but only when the user touches that particular subview). UIScrollView passes on touches to its subviews by default (see touchesShouldBegin:withEvent:inContentView: in UIScrollView).

score 5 · Answer 4 · answered Dec 01 '09 at 22:32

You can also respond to these events in your controller. For that to work, you have to define this feature (in your controller):

- (BOOL)canBecomeFirstResponder {
    return YES;
}

Then, in 'viewDidAppear', you need to call 'becomeFirstResponder':

- (void)viewDidAppear:(BOOL)animated {
    [super viewDidAppear:animated];
    [self becomeFirstResponder];

score 1 · Answer 5 · edited May 23 '17 at 12:13

1

New updates on the issue here (including a link to ZoomScrollView source code + some excellent explanation on UIScrollView internals) . Also, check out Apple's updated ScrollViewSuite example.

edited May 23 '17 at 12:13

Community

1
1

answered Sep 03 '10 at 20:55

DenTheMan

1,277
2
13
21

score 0 · Answer 6 · answered Nov 06 '09 at 14:18

0

You should add touchesBegan:withEvent: on your UIScrollView, not on the UIScrollViewDelegate. UIScrollView is a sub class of UIResponder, which has the touch events.

answered Nov 06 '09 at 14:18

nash

2,181
15
16

What if the `UIScrollView` **IS** the `UIScrollViewDelegate`? – aleclarson Mar 12 '14 at 08:14

score 0 · Answer 7 · answered Oct 06 '17 at 09:47

Rajneesh071 answer in swift 4 Change the custom class of scrollView in storyboard to CustomScrollView

import Foundation

class CustomScrollView: UIScrollView {
    override func touchesBegan(_ touches: Set<UITouch>, with event: UIEvent?) {
        if !isDragging {
            next?.touchesBegan(touches, with: event)
        } else {
        super.touchesBegan(touches, with: event)
        }
    }
}

score 0 · Answer 8 · answered Mar 02 '18 at 05:55

0

You need to subclass scroll view and then implement the touchesBegan method.You need also set the delayTouchDown property to false.

answered Mar 02 '18 at 05:55

Tibin Thomas

1,365
2
16
25

UIScrollView touchesBegan

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