get the latitude and longitude from a point in MKMapView?
I just want to implement a small function that allows system to obtain a location on MKMapView
where the user has 开发者_开发知识库touched. I wrote some code as following:
#import "UIViewTouch.h"
@implementation UIViewTouch
@synthesize viewTouched;
- (UIView *)hitTest:(CGPoint)point withEvent:(UIEvent *) event{
NSLog(@"Hit Test");
NSLog(@"x = %f, y = %f", point.x, point.y);
MKMapView *mapView = (MKMapView *) [self.subviews objectAtIndex:0];
CLLocationCoordinate2D coordinate = [mapView convertPoint:point toCoordinateFromView:self];
NSLog(@"Lat = %f, Lng = %f", coordinate.latitude,coordinate.longitude);
//MapAnnotation is a custom class and confirms to MKAnnotation.
MapAnnotation *annotation = [[MapAnnotation alloc] initWithCoordinate:coordinate];
[mapView addAnnotation:annotation];
return [super hitTest:point withEvent:event];
}
- (BOOL) pointInside:(CGPoint)point withEvent:(UIEvent *)event{
return [super pointInside:point withEvent:event];
}
@end
It can work fine if I don't add a annotation on the MKMapView
, otherwise the app will throw a exception:
Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[TESTViewController openCallout:]: unrecognized selector sent to instance 0x6b60180'
Any ideas?
Thanks a lot!
Your code looks fine to me. What does the call stack look like at the exception point? Do you have any calls to the apparently nonexistent selector -openCallout:
?
Not entirely related, but you should implement touch-handling in touchesBegan:withEvent:. Spontaneously adding an annotation in hitTest:withEvent: is dubious at best, since it'll probably add a view to the map view...
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