ios - 通过 MKAnnotation CalloutAccessoryControlTapped 传递自定义属性

Question

我正在尝试执行通过 MKAnnotation 传递自定义属性 (placeId) 的简单功能。我已经使用名为“MapViewAnnotation”的自定义类设置了所有内容。

我只想在用户激活 CalloutAccessoryControlTapped 时将一个附加值从 MapViewController 传递到 DetailViewController。我可以让标题/副标题正常工作，但我需要修改我的代码以允许自定义变量。

我已经尝试了一段时间，但无法正常工作。任何帮助都会很棒!谢谢!

MapViewAnnotation.h

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

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

- (id)initWithTitle:(NSString *)ttl andCoordinate:(CLLocationCoordinate2D)c2d;

@end

MapViewAnnotation.m

@implementation MapViewAnnotation

@synthesize title, coordinate, subtitle;

- (id)initWithTitle:(NSString *)ttl andCoordinate:(CLLocationCoordinate2D)c2d {
    title = ttl;
    coordinate = c2d;
    subtitle = @"Test Subtitle";
    return self;
}

@end

在 MapViewController.m 中创建注释 - 在这里你可以看到我正在使用副标题传递 placeId(底线)

location.latitude = [dictionary[@"placeLatitude"] doubleValue];
location.longitude = [dictionary[@"placeLongitude"] doubleValue];    

newAnnotation = [[MapViewAnnotation alloc] initWithTitle:dictionary[@"placeName"]
                                               andCoordinate:location];

newAnnotation.subtitle = dictionary[@"placeId"];

CalloutAccessoryControlTapped in MapViewController.m - 在这里你可以看到我将 placeId 保存到 NSUserDefaults

- (void)mapView:(MKMapView *)mapView annotationView:(MKAnnotationView *)view 
calloutAccessoryControlTapped:(UIControl *)control
{
    NSString *passedId = view.annotation.subtitle;
    [[NSUserDefaults standardUserDefaults]
    setObject:passedId forKey:@"passedId"];
    [[NSUserDefaults standardUserDefaults] synchronize];
}

Answer 1

为什么不在自定义 map View 注释中添加新属性？在MapViewAnnotation.h中添加

@property (nonatomic, strong) NSString *passedID;

然后，在 View Controller 中创建注释时，设置该属性而不是设置副标题:

newAnnotation = [[MapViewAnnotation alloc] initWithTitle:dictionary[@"placeName"]
                                               andCoordinate:location];

newAnnotation.passedID = dictionary[@"placeId"];

最后，在您的 CalloutAccessoryControlTapped 中，您将 MapViewAnnotation 转换为您的自定义类，然后访问 passedID 属性，而不是 subtitle 属性:

- (void)mapView:(MKMapView *)mapView annotationView:(MKAnnotationView *)view 
calloutAccessoryControlTapped:(UIControl *)control
{
    NSString *passedId = ((MapViewAnnotation*)view.annotation).passedID;
    [[NSUserDefaults standardUserDefaults]
    setObject:passedId forKey:@"passedId"];
    [[NSUserDefaults standardUserDefaults] synchronize];
}