How to block a gesture from superview to subview?

Question

I\'m writing a module that everytime I swipe on a view, two sub views with a half size of the view will be added. Those subviews have their own gestures (eg: pan,...). The f

Answer 1

You have to implement the UIGestureRecognizerDelegate method:

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer;

And add your controller as the delegate of the gesture recognizers. Then, when two gesture recognizers respond to a gesture, this method will be called and here you can implement the logic you want for your app.

In the interface declaration of the controller you have to type:

@interface testcViewController () 

Then, when creating the gesture recognizer:

UISwipeGestureRecognizer *swipe = [[UISwipeGestureRecognizer alloc] initWithTarget:self action:@selector(swipe)];
swipe.direction = UISwipeGestureRecognizerDirectionDown;
swipe.delegate = self;
[self.view addGestureRecognizer:swipe];

And then, finally, you add this method to the controller:

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer
{
    BOOL shouldInteract = NO;
    //Here you decide whether or not the two recognizers whould interact.
    return shouldInteract;
}

EDIT You can also implement

- (BOOL)gestureRecognizerShouldBegin:(UIGestureRecognizer *)gestureRecognizer;

And here, detect if you have already presented the subviews, and block any gesture you want.