MKPinAnnotationView 不起作用

Question

我想要一个MKMapView 显示带有披露按钮的注释，这些注释会导致像the Golden Gate Bridge annotation in this Apple sample app 这样的视图控制器。

我从 plist 加载坐标，注释正确显示为标题/副标题，但方法

- (MKAnnotationView *)mapView:(MKMapView *)theMapView viewForAnnotation:(id <MKAnnotation>)annotation

没有效果。

我想我必须以某种方式将注释与 pinannotations 联系起来？

MapViewController.h：

#import <UIKit/UIKit.h>
#import <MapKit/MapKit.h>
#import <CoreLocation/CoreLocation.h>
#import "Annotation.h"

@interface MapViewController : UIViewController<CLLocationManagerDelegate, MKMapViewDelegate>

@property (strong, nonatomic) CLLocationManager *location;
@property (nonatomic, retain) NSArray *data;    
@end

MapViewController.m：

#import "MapViewController.h"

@interface MapViewController ()
@property (nonatomic, weak) IBOutlet MKMapView *mapView;
@end

@implementation MapViewController
@synthesize data;
@synthesize location, minLatitude, maxLatitude, minLongitude, maxLongitude;

- (void)viewDidLoad
{
    NSString *dataPath = [[NSBundle mainBundle] pathForResource:@"City" ofType:@"plist"];
    self.data = [NSArray arrayWithContentsOfFile:dataPath];

    for (int i = 0; i < data.count; i++) {

        NSDictionary *dataItem = [data objectAtIndex:i];

        //Create Annotation
        Annotation *building = [[Annotation alloc] init];
        building.title = [dataItem objectForKey:@"Title"];
        building.subtitle = [dataItem objectForKey:@"Subtitle"];

        MKCoordinateRegion buildingcoordinates = { {0.0, 0.0}, {0.0, 0.0} };
        buildingcoordinates.center.latitude = [[dataItem objectForKey:@"Latitude"] floatValue];
        buildingcoordinates.center.longitude = [[dataItem objectForKey:@"Longitude"] floatValue];

        building.coordinate = buildingcoordinates.center;
        [self.mapView addAnnotation:building];

    }

    [super viewDidLoad];

}

- (MKAnnotationView *)mapView:(MKMapView *)theMapView viewForAnnotation:(id <MKAnnotation>)annotation
{
    if ([annotation isKindOfClass:[MKUserLocation class]])
        return nil;

        static NSString *pinIdentifier = @"pinIndentifier";

        MKPinAnnotationView *pinView = (MKPinAnnotationView *)
        [self.mapView dequeueReusableAnnotationViewWithIdentifier:pinIdentifier];
        if (pinView == nil)
        {
            // if an existing pin view was not available, create one
            MKPinAnnotationView *customPinView = [[MKPinAnnotationView alloc]
                                                  initWithAnnotation:annotation reuseIdentifier:pinIdentifier];
            customPinView.pinColor = MKPinAnnotationColorPurple;
            customPinView.animatesDrop = YES;
            customPinView.canShowCallout = YES;

            UIButton* rightButton = [UIButton buttonWithType:UIButtonTypeDetailDisclosure];
            [rightButton addTarget:self
                            action:@selector(showDetails:)
                  forControlEvents:UIControlEventTouchUpInside];
            customPinView.rightCalloutAccessoryView = rightButton;

            return customPinView;
        }
        else
        {
            pinView.annotation = annotation;
        }
        return pinView;
}

Annotation.h：

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

@interface Annotation : NSObject <MKAnnotation> {
    CLLocationCoordinate2D coordinate;
    NSString *title;
    NSString *subtitle;
}

@property(nonatomic, assign) CLLocationCoordinate2D coordinate;
@property(nonatomic, copy) NSString *title;
@property(nonatomic, copy) NSString *subtitle;

@end

Annotation.m：

#import "Annotation.h"

@implementation Annotation

@synthesize coordinate, title, subtitle;

@end

Answer 1

很可能地图视图的delegate 未设置，这意味着viewForAnnotation 委托方法将不会被调用。

由于您已将 mapView 声明为 IBOutlet，因此在 xib 中，请确保地图视图的 delegate 已连接到文件的所有者。

或者，在 MapViewController 中 viewDidLoad 方法的顶部，以编程方式设置它：

mapView.delegate = self;