UILongPressGestureRecognizer on MKAnnotationView not working for single touch

问题

I've been trying to use a UILongPressGestureRecognizer in a MKAnnotationView subclass. Interestingly the gesture recognizer only triggers when using two ore fingers/touches.

What prevents the gesture recognizer to get triggered with only one touch?

Implementation

UILongPressGestureRecognizer *pressRecognizer = [[UILongPressGestureRecognizer alloc] initWithTarget:self
                                                                                                      action:@selector(handleLongPress:)];
pressRecognizer.minimumPressDuration = 0.25;
pressRecognizer.numberOfTapsRequired = 0;
pressRecognizer.numberOfTouchesRequired = 1;

The same implementation in a normal UIView shows the expected behaviour working with one touch. Yet it's possible to use touchesBegan: and touchesEnded: to get a long press gesture working I'm still curious what the reason for this is.

回答1:

Have you seen this question ?

For using my UILongPressGestureRecognizer I disabled AnnotationView and added GestureRecognizer to it:

[ann_view setEnabled:NO];
UILongPressGestureRecognizer* long_press = [[UILongPressGestureRecognizer alloc] initWithTarget:self action:@selector(longPressAnnotationView:)];
long_press.minimumPressDuration = 1.5;
[ann_view addGestureRecognizer:long_press];
[long_press release];

来源：https://stackoverflow.com/questions/8021019/uilongpressgesturerecognizer-on-mkannotationview-not-working-for-single-touch