Subclassed UIScrollView detects touches within buttons but is otherwise unresponsive to user interaction

Question

I have a vertical UIScrollView that has several large buttons taking up most of the space in the scroll view. For this reason I've had to subclass the scroll view following this post ios 8 - buttons in horizontal scroll view intercepting pan event - scroll does not work) and override the following class method:

- (BOOL)touchesShouldBegin:(NSSet *)touches withEvent:(UIEvent *)event inContentView:(UIView *)view
{
    static int count = 0;
    count++;
    NSLog(@"calling this function 2");
    NSLog(@"count = %d", count);
    UITouch *touch = [touches anyObject];

    if(touch.phase == UITouchPhaseMoved)
    {
        NSLog(@"UITouchPhaseMoved so returning no");
        return NO;
    }


    else
    {
        NSLog(@"returning super");
        NSLog(@"returning whatever this value is %d 0/1", [super touchesShouldBegin:touches withEvent:event inContentView:view]);
        [super touchesShouldBegin:touches withEvent:event inContentView:view];
        return [super touchesShouldBegin:touches withEvent:event inContentView:view];
    }
}

When I run my app, this above function is called when a button is tapped but the function is not called when I drag anywhere in the scroll view, inside or outside a button. And the scroll view doesn't scroll regardless of where I try to drag.

Here's all my code related to the scroll view (it's set up with IB):

            smallView.scrollEnabled = YES;
            smallView.contentSize = CGSizeMake(smallView.frame.size.width, smallView.frame.size.height*1.4);
            smallView.delegate = self;

And here's the buttons-related code in case that matters:

NSArray *buttonsArray = @[button1, button2, button3, button4, button5];
for (int i = 0; i < [buttonsArray count]; i++) {
    UIButton *button = buttonsArray[i];
    button.tag = i+1;
    [button addTarget:self action:@selector(p_motivationButtonPressed:) forControlEvents:UIControlEventTouchUpInside];
    button.titleLabel.lineBreakMode = NSLineBreakByWordWrapping;
    button.titleLabel.textAlignment = NSTextAlignmentCenter;
}

Why is my scroll view not scrolling and not even calling touchesShouldBegin?

@TejaNandamuri I don't know, that can change, but the function never enters that branch of the logic anyway. — helloB, Mar 25 '16 at 17:17
where did u implement the touched moved method ? the touches begin method cannot intercept touched moved event. It will only detect the start point of the touch event. — Teja Nandamuri, Mar 25 '16 at 17:18
have aloot at the fifth paragraph https://developer.apple.com/library/ios/documentation/UIKit/Reference/UIScrollView_Class/#//apple_ref/occ/instm/UIScrollView/touchesShouldBegin:withEvent:inContentView: — Muhammad Zohaib Ehsan, Mar 25 '16 at 18:55
It explains why scrolling event aren't sent to the subviews. — Muhammad Zohaib Ehsan, Mar 25 '16 at 18:55

score 0 · Answer 1 · edited Mar 25 '16 at 18:12

0

Subclass UIScrollView and override touchesShouldCancelInContentView() as follows:

override func touchesShouldCancelInContentView(view: UIView) -> Bool {
    if let _ = view as? UIControl {
        return true
    }
    else {
        return super.touchesShouldCancelInContentView(view)
    }
}

edited Mar 25 '16 at 18:12

buczek

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answered Mar 25 '16 at 17:39

bsmith11

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Subclassed UIScrollView detects touches within buttons but is otherwise unresponsive to user interaction

1 Answers1