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MapPin.h：

#import <Foundation/Foundation.h>
#import <MapKit/MapKit.h>

@interface MapPin : NSObject<MKAnnotation> {
CLLocationCoordinate2D coordinate;
NSString *title;
NSString *subtitle;
}
@property (nonatomic,readwrite,assign)CLLocationCoordinate2D coordinate;
- (id)initWithCoordinates:(CLLocationCoordinate2D)location placeName:(NSString  *)placeName description:(NSString *)description;
-(void)setCoordinate:(CLLocationCoordinate2D)newCoordinate;
@end

这是 MapPin.m

#import "MapPin.h"

@implementation MapPin
@synthesize coordinate;

-(NSString *)subtitle{
return nil;
}
-(NSString *)title{
     return nil;
    }
-(id)initWithCoordinates:(CLLocationCoordinate2D)location placeName:(NSString *)placeName description:(NSString *)description{
    coordinate=location;
    return self;

}
-(CLLocationCoordinate2D)location{
    return coordinate;
}
-(void)setCoordinate:(CLLocationCoordinate2D)newCoordinate{
     coordinate=newCoordinate;
}

@end

在 ViewController.h 我采用了 MKMapViewDelegate 协议。这是 ViewController.m ：

-(MKAnnotationView *)mapView:(MKMapView *)mapView viewForAnnotation:(id<MKAnnotation>)annotation{
    MKPinAnnotationView *pin = (MKPinAnnotationView *)[self.MyMap dequeueReusableAnnotationViewWithIdentifier:@"myPin"];
    if(pin == nil){
        pin=[[MKPinAnnotationView alloc]initWithAnnotation:annotation reuseIdentifier:@"myPin"];

    }
     else{
        pin.annotation=annotation;
    }
    pin.draggable=YES;
return  pin;
}
//Add Location button
 - (IBAction)AddPin:(id)sender {
    CLLocationCoordinate2D center;
    center.latitude=Locate.location.coordinate.latitude;
    center.longitude=Locate.location.coordinate.longitude;
    MKCoordinateRegion region;
    region.center=center;
    region.span.latitudeDelta=0.2f;
    region.span.longitudeDelta=0.2f;
    MapPin *myPin = [[MapPin alloc]initWithCoordinates:self.MyMap.centerCoordinate placeName:@"LoMinder!" description:@"Set Location for LoMinder!"];
    [_MyMap addAnnotation:myPin];
 }
 //Dropping the pin:
    - (void)mapView:(MKMapView *)mapView
 annotationView:(MKAnnotationView *)annotationView
 didChangeDragState:(MKAnnotationViewDragState)newState
   fromOldState:(MKAnnotationViewDragState)oldState
{
    //Region
    MKCoordinateRegion myRegion;
    //Center
    CLLocationCoordinate2D center;
    if (newState == MKAnnotationViewDragStateStarting)
    {
         [_MyMap setRegion:myRegion animated:YES];
    }
    if(newState == MKAnnotationViewDragStateDragging)
    {
        myRegion.center=annotationView.annotation.coordinate;
        myRegion.span.latitudeDelta=0.2f;
        myRegion.span.longitudeDelta=0.2f;
        [_MyMap setRegion:myRegion animated:YES];
    }
    if(newState==MKAnnotationViewDragStateEnding)
    {
        arrived=self.MyMap.centerCoordinate;
        center=annotationView.annotation.coordinate;
        myRegion.center=center;
        myRegion.span.latitudeDelta=0.2f;
        myRegion.span.longitudeDelta=0.2f;
        [_MyMap setRegion:myRegion animated:YES];
     }
  }

///// 我还将 MapPin.h 导入到 ViewController 中。当我运行我的应用程序时，我应该按添加位置按钮以获取注释图钉，我按下按钮，注释图钉出现在地图上，但问题是当我尝试拖动它时，它似乎不可拖动。请人们帮忙。谢谢 ：）

4

1 回答 1

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通过更改 MapPin.m 中的 title 方法解决 使其返回除 nil 以外的任何内容。

于 2013-04-12T12:29:45.477 回答