Unrecognized selector sent to instance?

问题

How to fix such an error: unrecognized selector sent to instance ?

CLLocationCoordinate2D userCoordinate = userLocation.location.coordinate;
CGFloat latDelta = rand()*.035/RAND_MAX -.02;
CGFloat longDelta = rand()*.03/RAND_MAX -.015;
CLLocationCoordinate2D newCoord = { userCoordinate.latitude + latDelta, userCoordinate.longitude + longDelta };
myPoint *mp = [[myPoint alloc] initWithCoordinate:newCoord title:[NSString stringWithFormat:@"Vitaliy Home %d",i] subTitle:@"Home Sweet Home"];
[mv addAnnotation:mp]; //mv - (MKMapView *)mv

Error is on line :

myPoint *mp = [[myPoint alloc] initWithCoordinate:newCoord title:[NSString stringWithFormat:@"Vitaliy Home %d",i] subTitle:@"Home Sweet Home"];

class myPoint:

@interface myPoint : NSObject<MKAnnotation> {
    NSString *title;
    NSString *subTitle;
    CLLocationCoordinate2D coordinate;
}

@property (nonatomic,readonly) CLLocationCoordinate2D coordinate;
@property (nonatomic,copy) NSString *title;
@property (nonatomic,copy) NSString *subTitle;

- (id)initWithCoordinate:(CLLocationCoordinate2D) c title:(NSString *) t subTitle:(NSString *) st;

@end

Thank you.

回答1:

You are probably doing something like this in the initWithCoordinate:... method:

self.coordinate = c;

This is not a simple assignment, this is calling a method (property setter setCoordinate:) which is not there and it ends in exception.

Fix compiler warnings!

回答2:

The problem was in not correct implementation of the method, thanks @BrunoKoga.

来源：https://stackoverflow.com/questions/16843675/unrecognized-selector-sent-to-instance