使用UILongPressGestureRecognizer删除MKA注释

Question

I can't seem to get the long press gesture recognizer to work on the annotation view, only the map view. The abridged version of my code is:

@interface AppDelegate : UIResponder <UIApplicationDelegate, CLLocationManagerDelegate, MKMapViewDelegate, UIGestureRecognizerDelegate, UIActionSheetDelegate>
{
    CLLocationManager *locationManager;

    // Views
    IBOutlet MKMapView *mapView;
    IBOutlet MKAnnotationView *annotationView;

    UILongPressGestureRecognizer *longPress;
}

and parts of the implementation in AppDelegate.m ...

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{

    locationManager = [[CLLocationManager alloc] init];
    [locationManager setDelegate:self];

    [mapView setShowsUserLocation:YES];

    longPress = [[UILongPressGestureRecognizer alloc] initWithTarget:self 
                                                         action:@selector(deleteSelectedAnnotation:)];

    [[self window] makeKeyAndVisible];
    return YES;
}

- (void)mapView:(MKMapView *)mv didAddAnnotationViews:(NSArray *)views
{
    annotationView = [views objectAtIndex:0];
    [annotationView addGestureRecognizer:longPress];
    id <MKAnnotation> mp = [annotationView annotation];
    MKCoordinateRegion region = MKCoordinateRegionMakeWithDistance([mp coordinate], 250, 250);
    [mv setRegion:region animated:YES];
}

- (IBAction)deleteSelectedAnnotation:(UIGestureRecognizer *)sender
{
    if (sender.state == UIGestureRecognizerStateBegan)
    {
        NSLog(@"long press");
        UIActionSheet *actionSheet = [[UIActionSheet alloc] initWithTitle:@"Delete Record?" 
                                                                 delegate:self 
                                                        cancelButtonTitle:nil 
                                                   destructiveButtonTitle:nil 
                                                        otherButtonTitles:@"Yes",@"No",nil];
                                      [actionSheet showInView:mapView];
                                      [actionSheet release];
    }
}

So this whole thing works if i change the view object in line [annotationView addGestureRecognizer:longPress] to mapView . But I only want the action to occur if the user is pressing the annotation, not anywhere on the map. What am I doing wrong?

Thanks.

Answer 1

You can check if the touch is inside the annotation view's bounds:

UIView *annotationView = [mapView viewForAnnotation:myAnnotation];
if ( annotationView && CGRectContainsPoint(annotationView.bounds, [sender locationInView:annotationView]) )
{
    // we can continue
}