Question

我正在使用Mapkit，我必须在地图中显示注释，但我无法显示注释。这是我的代码：

@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;
}

上面的代码工作正常并显示地图但不显示注释。

Answer 1

通常，符合MKAnnotation协议的类不是视图控制器，而是数据类。

您需要创建另一个类，我将其称为“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

然后，在MyMapView班级的适当位置添加：

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

其他与您合作的Objective-C开发人员将会欣赏以下几点：

为避免混淆，如果它来自MyMapView，请不要调用类UIViewController。改为称呼MyMapViewController。
类以大写字母开头，变量以小写字母开头。两者都是CamelCased。 Obj_Map_View应为objMapView。

Answer 2

要添加注释，请使用：addAnnotation:

了解它here

在地图工具箱中显示注释

2 个答案: