在地圖工具包中顯示註釋

Question

我正在使用Mapkit，並且必須在地圖中顯示註釋，但我無法顯示註釋。這是我的代碼：

@interface MyMapView : UIViewController <MKAnnotation,MKMapViewDelegate>{ 

MKMapView *Obj_Map_View; 
MKPlacemark *pmark; 
MKReverseGeocoder *geocoder1; 
} 

@end 


#import "MyMapView.h" 
@implementation MyMapView 

- (id)init { 
    if (self = [super init]) { 

    } 
    return self; 
} 

- (void)loadView { 
    [super loadView]; 
    Obj_Map_View = [[MKMapView alloc]initWithFrame:self.view.bounds]; 
    Obj_Map_View.showsUserLocation =YES; 
    Obj_Map_View.mapType=MKMapTypeStandard; 
    [self.view addSubview:Obj_Map_View]; 
    Obj_Map_View.delegate = self; 

    CLLocationCoordinate2D cord = {latitude: 19.120000, longitude: 73.020000}; 
    MKCoordinateSpan span = {latitudeDelta:0.3, longitudeDelta:0.3}; 
    MKCoordinateRegion reg= {cord,span}; 
    [Obj_Map_View setRegion:reg animated:YES]; 
    //[Obj_Map_View release]; 
} 

- (NSString *)subtitle{ 
    return @"Sub Title"; 
} 

- (NSString *)title{ 
    return @"Title"; 
} 

- (MKAnnotationView *) mapView:(MKMapView *)mapView viewForAnnotation:(id <MKAnnotation>) annotation 
{ 
    MKPinAnnotationView *annov = [[MKPinAnnotationView alloc]initWithAnnotation:annotation reuseIdentifier:@"Current location"]; 
    annov.animatesDrop = TRUE; 
    [annotation title]==@"Current location"; 
    annov.canShowCallout = YES; 
    [annov setPinColor:MKPinAnnotationColorGreen]; 
    return annov; 
} 

上面的代碼工作正常，並顯示一個地圖，但沒有註釋。

Answer 1

通常，符合MKAnnotation協議的類不是視圖控制器，它是數據類。

您需要創建另一個類，我將爲該示例調用「MyLandmarks」。

@interface MyLandmarks : NSObject <MKAnnotation> 
    // Normally, there'd be some variables that contain the name and location. 
    // And maybe some means to populate them from a URL or a database. 
    // This example hard codes everything. 

@end 


@implementation MyLandmarks 
-(NSString*)title { 
    return @"'ere I am, J.H."; 
} 

-(NSString*)subtitle { 
    return @"The ghost in the machine."; 
} 

-(CLLocationCoordinate2D) coordinate { 
    CLLocationCoordinate2D coord = {latitude: 19.120000, longitude: 73.020000}; 

    return coord; 
} 
@end 

然後，在你MyMapView類添加某個適當的：其他的Objective-C開發與您合作會明白

MyLandmark *landmark = [[[MyLandmark alloc]init]autorelease]; 
[Obj_Map_View addAnnotation:landmark]; 

幾個其他位：

• 爲了避免混淆，如果它從UIViewController下降，請不要致電MyMapView。改爲將其稱爲MyMapViewController。
• 類以大寫字母開頭，變量以小寫字母開頭。兩者都是CamelCased。 Obj_Map_View應該是objMapView。

Answer 2

要添加註釋使用：addAnnotation:

讀到它here