如何使用MKPointAnnotation向MKMapView添加注释？

Question

我试图弄清楚如何将MKAnnotation的实例添加到MKMapView。我无法弄清楚我做错了什么......一切似乎都没问题，直到我真的尝试将注释添加到mapView。然后我收到SIGABRT错误。这是我的代码：

lon = [[attributeDict objectForKey:@"long"] doubleValue];
lat = [[attributeDict objectForKey:@"lat"] doubleValue];
 MKPointAnnotation *point;
 CLLocation *theLocation = [[CLLocation alloc]initWithLatitude:lat longitude:lon];
 CLLocationCoordinate2D location;
 location.latitude = lat;
 location.longitude = lon;
 [point setCoordinate:(location)];
 [point setTitle:businessName];

 //ITS RIGHT HERE THAT I GET THE ERROR
 [theMap addAnnotation:point];

您是否必须首先设置地图的区域？

Answer 1

您需要分配并初始化point：

MKPointAnnotation *point = [[MKPointAnnotation alloc] init];