UILongPressGestureRecognizer recognizes touches outside its view - ios

Question

I have a subview of imageview with a PanGestureRecognizer, and the main view has a LongPressGestureRecognizer. I have added the longpress only to the view like this:
screenRecognize = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:#selector(screenTaped:)];
screenRecognize.minimumPressDuration = 0.0;
self.userInteractionEnabled = YES;
[self addGestureRecognizer:screenRecognize];
And here's the imageview:
imageViewPanRecognizer = [[UIPanGestureRecognizer alloc] initWithTarget:self action:#selector(imageViewPulled:)];
imageView = [[UIImageView alloc] initWithFrame:CGRectMake(310, 50, 10, 40)];
imageView.image = [UIImage imageNamed:#"image.png"];
imageView.userInteractionEnabled = YES;
[imageView addGestureRecognizer:imageViewPanRecognizer];
[self addSubview:imageView];
When I touch the imageView, the UILongPressRecognizer is fired. Why is this?

Answer 1

The answer is already in your question. You set
screenRecognize.minimumPressDuration = 0.0;
that means, UILongPressGestureRecognizer will work as like UITapGestureRecognizer. By the line
[self addGestureRecognizer:screenRecognize];
you active this gesture on all over the self.
Now when you add imageView in the self, the imageView will also response to the UILongPressGestureRecognizer as well as UIPanGestureRecognizer which is only active on the imageView. As a result touching on the imageView is firing UILongPressGestureRecognizer.
To solve this problem you can try by increasing the minimumPressDuration value.

Answer 2

1) Why you use long gesture with minimumPressDuration=0? Can not properly use pan gesture?
2) If you want that gestures work together, try something like this:
longGesture.delegate = self;
...
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer
{
return YES;
}
3) If you whan if user pan to UIImageView long gesture disable, try something like this:
self.tag = 1;
longGesture.delegate = self;
...
- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch
{
return touch.view.tag == 1;
}