iOS开发--MKMapView添加UIPanGestureRecognizer

    当我们想给MKMapView添加拖动手势时，第一个想法多是这样：

- (void)viewDidLoad
{
    //....
    UIPanGestureRecognizer *panGesture = [[UIPanGestureRecognizer alloc] initWithTarget:self action:@selector(handlePan:)];
    [self.mapView addGestureRecognizer:panGesture];
}

- (void)handlePan:(UIPanGestureRecognizer*) recognizer
{
    NSLog("handlePan");
}
- (void)view