Question

I set up a mechanism where a modal view controller can be dismissed by tapping the outside of the view. The set up is as follows:

- (void)viewDidAppear:(BOOL)animated
{
    UITapGestureRecognizer *recognizer = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(handleTapBehind:)];
    [recognizer setNumberOfTapsRequired:1];
    recognizer.cancelsTouchesInView = NO; //So the user can still interact with controls in the modal view
    [self.view.window addGestureRecognizer:recognizer];

}

- (void)handleTapBehind:(UITapGestureRecognizer *)sender
{
    if (sender.state == UIGestureRecognizerStateEnded)
    {
        CGPoint location = [sender locationInView:nil]; //Passing nil gives us coordinates in the window

        //Then we convert the tap's location into the local view's coordinate system, and test to see if it's in or outside. If outside, dismiss the view.

        if (![self.view pointInside:[self.view convertPoint:location fromView:self.view.window] withEvent:nil]) 
        {
            [self dismissModalViewControllerAnimated:YES];
            NSLog(@"There are %d Gesture Recognizers",[self.view.window gestureRecognizers].count);
            [self.view.window removeGestureRecognizer:sender];
        }
    }
}

This works amazing for dismissing a single modal view. Now suppose I have two modal views, one called from within the root view controller (View A) and then another modal called from within the first modal (View B)

Kind of like this:

Root View -> View A -> View B

When I tap to dismiss View B, all is well. However I get an EXC_BAD_ACCESS error when I try to dismiss View A. After turning on zombies, it seems that View B is still getting the message handleTapBehind: sent to it, even though it’s been dismissed and out of memory after View B was closed.

My question is why is View B still being messaged? (handleTapBehind: make sure that gesture recognizer should have been removed from the associated window.) And how can I get it to be sent to View A after View B is already dismissed.

PS. The code above appears both inside the controller for View A and for View B, and it is identical.

EDIT

Here’s how I am calling the modal view controller, this code is inside a view controller that is within the standard view hierarchy.

LBModalViewController *vc = [[LBModalViewController alloc] initWithNibName:@"LBModalViewController" bundle:nil];
[vc.myTableView setDataSource:vc];
[vc setDataArray:self.object.membersArray];

[vc setModalPresentationStyle:UIModalPresentationFormSheet];
[vc setModalTransitionStyle:UIModalTransitionStyleFlipHorizontal];

[vc.view setClipsToBounds:NO];

[self presentViewController:vc animated:YES completion:nil];

// This is a hack to modify the size of the presented view controller
CGPoint modalOrigin = vc.view.superview.bounds.origin;
[[vc.view superview] setBounds:CGRectMake(modalOrigin.x, modalOrigin.y, 425, 351)];
[vc.view setBounds:CGRectMake(modalOrigin.x, modalOrigin.y, 425, 351)];

That’s pretty much it, everything else is pretty standard.

Answer 1

[self dismissModalViewControllerAnimated:YES];

[self.view.window removeGestureRecognizer:sender];

Should be:

[self.view.window removeGestureRecognizer:sender];

[self dismissModalViewControllerAnimated:YES];

else you will get undefined results.