iOS- MKMapKit-如何在用户位置上放置注释？

Question

我的应用程序上有用户位置，但如何在当前用户位置上添加注释？我是否必须获取用户位置的经度和纬度并以这种方式删除注释？或者我该怎么做？

Answer 1

1. 首先导入必要的框架(CoreLocation 和 MapKit)。
2. 然后创建 Objective-C NSObject 类 Annotation

3. 设置它的.h:

   #import <Foundation/Foundation.h>
   
   #import <CoreLocation/CoreLocation.h>
   
   #import <MapKit/MapKit.h>
   
   @interface Annotation : NSObject <MKAnnotation> 
   
   @property (nonatomic) CLLocationCoordinate2D coordinate;
   @property (nonatomic, copy) NSString *title;
   @property (nonatomic, copy) NSString *subtitle;
   
   @end
   

4. 设置它的 .m:

   #import "Annotation.h"
   
   @implementation Annotation
   @synthesize coordinate, title, subtitle;
   
   @end
   

   1. 设置viewDidLoad

         if ([CLLocationManager locationServicesEnabled]) {
      
         locationManager = [[CLLocationManager alloc] init];
      
         [locationManager setDelegate:self];
      
         [locationManager setDesiredAccuracy: kCLLocationAccuracyBestForNavigation];
      
         [locationManager startUpdatingLocation];
      
         }
      
        self.mapView.delegate = self; 
      

   2. 设置didUpdateToLocation

         // IMPORT ANNOTATION
      
         - (void)locationManager:(CLLocationManager *)manager didUpdateToLocation:(CLLocation *)newLocation fromLocation:(CLLocation *)oldLocation {
      
      
         [locationManager stopUpdatingLocation];
      
         double miles = 3.10686;
         double scalingFactor = ABS((cos(2 * M_PI * newLocation.coordinate.latitude / 360.0)));
      
         MKCoordinateSpan span;
      
         span.latitudeDelta = miles/69.0;
         span.longitudeDelta = miles/(scalingFactor * 69.0);
      
         MKCoordinateRegion region;
         region.span = span;
         region.center = newLocation.coordinate;
      
         [self.mapView setRegion:region animated:YES];
      
         Annotation *annot = [[Annotation alloc] init];
         annot.coordinate = newLocation.coordinate;
      
         [self.mapView addAnnotation:annot];
      
           }