Question

i am trying to implement my own gesture recognizer in addition to the one already used by the MKMapView. Right now i can tap on the map and set a pin. This behavior is realized by my UITapGestureRecognizer. When i tap on a pin that already exists, my gesture recognizer does nothing, but instead the callout bubble of this pin is shown. The UIGestureRecognizerDelegate looks like this:

-(BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldReceiveTouch:(UITouch *)touch
{
    if (gestureRecognizer == self.tapRecognizer) 
    {
        bool hitAnnotation = false;
        int count = [self.mapView.annotations count];
        int counter = 0;

        while (counter < count && hitAnnotation == false ) 
        {
            if (touch.view == [self.mapView viewForAnnotation:[self.mapView.annotations objectAtIndex:counter]]) 
            {
                hitAnnotation = true;
            }
            counter++;
        }
        if (hitAnnotation) 
        {
            return NO;
        }

    }
    return YES; 
}

This works fine. My only problem are the callout bubbles of the pins and the double tap. Normally the double tap is used for zooming in. This still works but in addition to this, i also get a new pin. Is there any way to avoid this?

The other problem occurs with the callout bubble of a pin. I can open the bubble by tapping on the pin without setting a new pin at this place (see code above) but when i want to close the bubble by tapping on it, another pin is set. My problem is, that i cannot check with touch.view , if the user tapped on a callout bubble, because it is not a regular UIView as far as i know. Any ideas or workarounds for this problem?

Thanks

Answer 1

I had the same problem as your first problem: distinguishing double taps from single taps in an MKMapView. What I did was the following:

[doubleTapper release];
doubleTapper = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(mapDoubleTapped:)];
doubleTapper.numberOfTapsRequired = 2;
doubleTapper.delaysTouchesBegan = NO;
doubleTapper.delaysTouchesEnded = NO;
doubleTapper.cancelsTouchesInView = NO;
doubleTapper.delegate = self;

[mapTapper release];
mapTapper = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(mapTapped:)];
mapTapper.numberOfTapsRequired = 1;
mapTapper.delaysTouchesBegan = NO;
mapTapper.delaysTouchesEnded = NO;
mapTapper.cancelsTouchesInView = NO;
[mapTapper requireGestureRecognizerToFail:doubleTapper];

and then implemented the following delegate method:

- (BOOL)gestureRecognizer:(UIGestureRecognizer *)gestureRecognizer shouldRecognizeSimultaneouslyWithGestureRecognizer:(UIGestureRecognizer *)otherGestureRecognizer
{
    return YES;
}

Using requireGestureRecognizerToFail: allows the app to distinguish single taps from double taps and implementing gestureRecognizer:shouldRecognizeSimultaneouslyWithGestureRecognizer: ensures that double taps are still forwarded to the MKMapView so that it continues zooming normally. Note that doubleTapper doesn’t actually do anything (in my case, except log debug messages). It’s simply a dummy UIGestureRecognizer that’s used to help separate single taps from double taps.