Objective-C。 NSString 改为 NSCFNumber

Question

我在 Objective-C 中有一些代码。我想，我收到了 NSString 类型，但是当我尝试将它保存在 Core Data 中时，出现 user.clientID = clientID; 错误，例如：

*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: 'Unacceptable type of value for attribute: property = "clientID"; desired type = NSString; given type = __NSCFNumber; value = 29.'

所以，这是我的代码：

我的数据管理器单例PKDataManager.h

+(PKDataManager*) sharedManager;

- (void)updateCoreDataUserWithID:(NSString*) userID
                 andClientID:(NSString*) clientID;

PKDataManager.m

- (void)updateCoreDataUserWithID:(NSString*) userID
                 andClientID:(NSString*) clientID{

       PKUser*user = [NSEntityDescription 
       insertNewObjectForEntityForName:@"PKUser" 
       inManagedObjectContext:self.managedObjectContext];
       user.userID = userID;
       user.clientID = clientID; ///// error showing here
       [self.managedObjectContext insertObject:user];
       [self.managedObjectContext save:nil];
}

我的单身人士 API PKServerManager.h

+ (PKServerManager*) sharedManager;

- (void) sendUserID:(NSString*) userID
              onSuccess:(void(^)(NSString* clientID)) success
              onFailure:(void(^)(NSError* error, NSInteger statusCode)) failure;

PKServerManager.m

- (void) sendUserID:(NSString*) userID
                  onSuccess:(void(^)(NSString* clientID)) success
                  onFailure:(void(^)(NSError* error, NSInteger statusCode)) failure{
        NSDictionary* params =
        [NSDictionary dictionaryWithObjectsAndKeys:
         userID, @"userID", nil];
        [self.requestOperationManager
         POST:@"app/registration"
         parameters:params
         progress:nil
         success:^(NSURLSessionTask *task, NSDictionary* responseObject) {
            NSLog(@"JSON: %@", responseObject);
            NSString* clientID = (NSString*)[responseObject objectForKey:@"clientId"];
            if (success) {
                success(clientID);
            }
         } failure:^(NSURLSessionTask *operation, NSError *error) {
         }];
}

和我的代码： PKProfile.m

[[PKServerManager sharedManager]
     sendUserID:profile.userID
     onSuccess:^(NSString* clientID) {
         NSLog(@"clientID %@", clientID);
         [[PKDataManager sharedManager] updateCoreDataUserWithID: profile.userID
                                                     andClientID: clientID];
     }
     onFailure:^(NSError *error, NSInteger statusCode) {
     }];

Answer 1

在你的PKServerManager.m

替换以下代码行：

NSString* clientID = (NSString*)[responseObject objectForKey:@"clientId"];

和

NSString* clientID = [NSString stringWithFormat:@"%@",[responseObject objectForKey:@"clientId"]];

Answer 2

您的错误告诉您响应包含客户端 ID 的数值（并且在 responseObject 中表示为 NSNumber；NSCFNumber 是更广泛的 NSNumber class 簇）。您的 JSON 回复似乎包含类似以下内容：

{
    ...,
    "clientId": 42
}

而不是

{
    ...,
    "clientId": "42"
}

与其关注如何将此 NSNumber 转换为 NSString，我更倾向于考虑将整个应用程序中的客户端 ID 更改为 NSInteger（或NSNumber)。如果这些 ID 确实是数值，最好有一个类型来反映这一点。

Objective-C。 NSString 改为 NSCFNumber

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