iOS 大头针的基本使用

1.导入头文件

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

2.为成员变量mapView添加手势识别

1 - (void)viewDidLoad
2 {
3     [super viewDidLoad]; 
4     // 添加手势识别
5     [self.mapView addGestureRecognizer:[[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(tapMapView:)]];
6 }

3.实现目标方法

 1 - (void)tapMapView:(UITapGestureRecognizer *)tap
 2 {
 3     // 获取所点击view的x,y坐标
 4     CGPoint point = [tap locationInView:tap.view];
 5     // x,y坐标转地理坐标
 6     CLLocationCoordinate2D coordinate = [self.mapView convertPoint:point toCoordinateFromView:tap.view];
 7     // 初始化大头针,之所以初始化大头针,是因为系统的MKAnnotation各项属性都是只读
 8     QKAnnotation *annotation = [[QKAnnotation alloc]init];
 9     // 设置大头针各项属性
10     annotation.title = @"我的大头针";
11     annotation.subtitle = @"我的大头针--子标题";
12     annotation.coordinate = coordinate;
13     // 在地图上添加大头针
14     [self.mapView addAnnotation:annotation];
15 }

3.1系统MKAnnotation各项属性,都是只读的

 1 #import <CoreGraphics/CoreGraphics.h>
 2 #import <CoreLocation/CoreLocation.h>
 3 #import <MapKit/MKFoundation.h>
 4 
 5 @protocol MKAnnotation <NSObject>
 6 
 7 // Center latitude and longitude of the annotion view.
 8 // The implementation of this property must be KVO compliant.
 9 @property (nonatomic, readonly) CLLocationCoordinate2D coordinate;
10 
11 @optional
12 
13 // Title and subtitle for use by selection UI.
14 @property (nonatomic, readonly, copy) NSString *title;
15 @property (nonatomic, readonly, copy) NSString *subtitle;
16 
17 // Called as a result of dragging an annotation view.
18 - (void)setCoordinate:(CLLocationCoordinate2D)newCoordinate NS_AVAILABLE(10_9, 4_0);
19 
20 @end

4.自定义大头针的.h文件,.m文件不需要修改

1 #import <MapKit/MapKit.h>
2 
3 @interface QKAnnotation : NSObject<MKAnnotation>
4 
5 @property (nonatomic,assign) CLLocationCoordinate2D coordinate;
6 @property (nonatomic, copy) NSString *title;
7 @property (nonatomic, copy) NSString *subtitle;
8 
9 @end

#注意:1.MKAnnotation是NSObject, 它是MKAnnotationView的一个属性

　　 2.MKAnnotationView继承自UIView

　　　 3.自定义大头针继承自NSObject. 遵守<MKAnnotation>协议,就获得了协议里申明的属性和方法.从3.1的代码可以看出,系统MKAnnotation对象,整个.h文件都是协议,coordinate是必须实现的属性,把readOnly删掉,并为coordinate属性添加assign.