获取 MKMapView 中某个点的纬度和经度？
我只是想实现一个小功能，允许系统获取用户触摸的 MKMapView 上的位置。我写了一些代码如下：
#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
如果我不在 MKMapView 上添加注释，它可以正常工作，否则应用程序将抛出异常：
由于未捕获的异常而终止应用程序 'NSInvalidArgumentException'，原因：'-[TESTViewController openCallout:]: 无法识别的选择器发送到实例 0x6b60180'
有什么想法吗？
多谢！
I just want to implement a small function that allows system to obtain a location on MKMapView where the user has 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!
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评论（2）
你的代码对我来说看起来不错。异常点处的调用堆栈是什么样的？您是否对明显不存在的选择器
-openCallout:进行了任何调用？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:?不完全相关，但您应该在 TouchesBegan:withEvent: 中实现触摸处理。在 hitTest:withEvent: 中自发添加注释充其量是可疑的，因为它可能会向地图视图添加一个视图......
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...