iphone - 在 ios 中创建自定义注释类时遇到问题

Question

我正在尝试制作一个自定义 MKAnnotation 类，以便它可以保存其他信息，但我不断收到此错误:

Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-    [AnnotationForId setCoordinate:]: unrecognized selector sent to instance 0x16f63340'

我已经尝试查找如何创建一个，并且我已经按照我在网上找到的内容进行了操作，但我对为什么我不断收到此错误感到困惑。

这是我的自定义注释类。

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

@interface AnnotationForId : NSObject <MKAnnotation >{
    NSString *title;
    NSString *subtitle;
    CLLocationCoordinate2D coordinate;
    NSInteger shopId;
}
@property(nonatomic)NSInteger shopId;
@property (nonatomic,  copy) NSString * title;
@property (nonatomic, copy) NSString * subtitle;
@property (nonatomic, readonly) CLLocationCoordinate2D  coordinate;
@end

我已经在 .m 类中合成了属性变量。

我尝试在我的主 Controller 中调用自定义类:

for(Shop *shops in feed.shops){
        NSLog(@"reached");
        AnnotationForId *shop = [[AnnotationForId alloc] init];
        CLLocationCoordinate2D coords = CLLocationCoordinate2DMake(shops.latitude, shops.longitude);
        shop.coordinate = coords;
        //[[CLLocationCoordinate2DMake(shops.latitude, shops.longtitude)]];
        shop.title = shops.name;
        shop.subtitle = @"Coffee Shop";
        [map addAnnotation:shop];
    }

对为什么这不起作用的任何帮助都会很棒。
谢谢。

Answer 1

似乎您正在尝试设置您的只读属性。

您将其声明为只读:

@property (nonatomic, readonly) CLLocationCoordinate2D  coordinate;

但随后您尝试使用 setter:

shop.coordinate = coords;

只读 意味着不会为其他类定义 setter 来利用。

编辑:
我认为您应该将便捷初始化程序添加到您的 AnnotationForId类如:

-(id)initWithCoordinate:(CLLocationCoordinate2D)coord
{ 
    self = [super init]; // assuming init is the designated initialiser of the super class
    if (self)
    { 
        coordinate = coord;
    }
    return self;  
}

因此，您的代码将如下所示:

for(Shop *shops in feed.shops){
        NSLog(@"reached");
        CLLocationCoordinate2D coords = CLLocationCoordinate2DMake(shops.latitude, shops.longitude);
        AnnotationForId *shop = [[AnnotationForId alloc] initWithCoordinate:coords];
        //[[CLLocationCoordinate2DMake(shops.latitude, shops.longtitude)]];
        shop.title = shops.name;
        shop.subtitle = @"Coffee Shop";
        [map addAnnotation:shop];
    }