Objective-C 为 AFNetworking 参数创建嵌套字典答案

【问题标题】：Objective-C creating a nested dictionary for AFNetworking parametersObjective-C 为 AFNetworking 参数创建嵌套字典
【发布时间】：2014-04-21 04:16:42
【问题描述】：

下面的代码引发了异常，我想不通是哪里出了问题：

-(NSDictionary*)prepareParameters:(NSArray*) p_currentParameters
{
    NSMutableDictionary *parameters = nil;
    if(self.p_currentParameters.count > 0 )
    {
        parameters = [[NSMutableDictionary alloc] init];
        for(int courseIdx = 0; courseIdx < p_currentParameters.count; courseIdx++)
        {
            CourseDetails* course = p_currentParameters[courseIdx];
            NSMutableDictionary *courseData = [[NSMutableDictionary alloc] init];
            courseData[@"courseIdx"] = [NSNumber numberWithInteger:course.id];
            courseData[@"isFavorite"] = @(course.isFavorite);
            courseData[@"isDeleted"] = @(course.isDeleted);
            [parameters setObject:courseData forKey:[NSNumber numberWithInt:courseIdx]];
        }
    }
    return parameters;
}

- (void)sendUserDataOnCourses:(NSArray*) p_currentCourses
{
    @try
    {
        NSString *baseURLString = <API ADDRESS>;
        AFHTTPRequestOperationManager *manager = [AFHTTPRequestOperationManager manager];
        NSMutableDictionary *parameters = [[NSMutableDictionary alloc] init];
        [parameters setObject:userUniqueId forKey:@"userID"];
        [parameters setObject:[self prepareParameters:p_currentCourses] forKey:@"courses"];
        NSError *error;
        NSData *jsonData = [NSJSONSerialization dataWithJSONObject:parameters options:NSJSONWritingPrettyPrinted error:&error];
        NSString *jsonString = [[NSString alloc] initWithData:jsonData encoding:NSUTF8StringEncoding];
        [manager POST:baseURLString
           parameters:[[NSDictionary alloc] initWithObjectsAndKeys:jsonString, @"request",nil]
              success:^(AFHTTPRequestOperation *operation, id responseObject){
                  <DO SOME STUFF>
              }
              failure:^(AFHTTPRequestOperation *operation, NSError *error){
                  NSLog(@"!!!!!!!!!!!!!! Error: %@ Error code: %d timeout counter:%d", error, error.code, timeoutfailure);
              }];
    }
    @catch (NSException *exception)
    {
        NSLog(@"sendUserDataOnCourses exception: %@",exception);
    }
}

此行发生异常：NSData *jsonData = [NSJSONSerialization dataWithJSONObject:parameters options:NSJSONWritingPrettyPrinted error:&error];，异常消息为：Invalid (non-string) key in JSON dictionary。

【问题讨论】：

[parameters setObject:courseData forKey:[NSNumber numberWithInt:courseIdx]];你不能那样做。文档上说 (developer.apple.com/documentation/foundation/…) All dictionary keys are instances of NSString. 而您使用的是NSNumber。

标签： objective-c json encoding afnetworking

【解决方案1】：

正如例外所说，您正在尝试将非字符串键（基本上是一个对象）插入字典。 JSON 序列化方法可能不知道如何序列化该对象，因为它可能没有实现可序列化协议。我要做的是检查您尝试插入字典的每个对象/值，看看它是什么。然后要么使它们可序列化，要么以字符串形式插入它们。

【讨论】：