Question

我有以下课程：

@interface Topics : NSObject {
    NSNumber * _until_id;
    NSArray * _topics;
}

@property (nonatomic, retain) NSNumber * until_id;
@property (nonatomic, retain) NSArray * topics;
@end

/////////////////////////////////////////////////////////////////////////

@class Login;

@interface Topic : NSObject {
    NSString * _name;
    Login * _creator;
    NSNumber * _message_count;
    NSNumber * _date_latest_message;
    NSNumber * _date_created;
    NSNumber * _tracked;
    NSNumber * _unread;
    NSNumber * _tid;
    NSString * _kind;
    NSNumber * _id;
}

@property (nonatomic, retain) NSString * name;
@property (nonatomic, retain) Login * creator;
@property (nonatomic, retain) NSNumber * message_count;
@property (nonatomic, retain) NSNumber * date_latest_message;
@property (nonatomic, retain) NSNumber * date_created;
@property (nonatomic, retain) NSNumber * tracked;
@property (nonatomic, retain) NSString * kind;
@property (nonatomic, retain) NSNumber * unread;
@property (nonatomic, retain) NSNumber * tid;
@property (nonatomic, retain) NSNumber * gid;
@property (nonatomic, readonly) NSString* topicNavURL;

@end

现在我正尝试使用以下方式访问特定主题名称：

RKObjectMapping* mapping = [RKObjectMapping mappingForClass:[TTTableTextItem class]];
 [mapping mapKeyPath:@"topics.name" toAttribute:@"text"];
 [mapping mapKeyPath:@"topics.topicNavURL" toAttribute:@"URL"];

然而，这失败了，因为它说找不到名称，因为主题是NSArray。如果我正在处理数组，有没有办法做KVC？那只是NSString吗？

Answer 1

是的，您无法使用KVC直接访问阵列。但是，您可以使用@sum，@ avg等聚合来计算总和，平均值

例如：@ sum.message_count将为您提供数组中所有消息的总消息数。您不必为此编写任何循环。

键值编码数组问题

1 个答案: