Question

所以我有一个函数可以创建这样的字典并返回该字典 -

- (NSDictionary *) createPostData{
    NSMutableDictionary * requestDictionary = [[NSMutableDictionary alloc]init];
    [requestDictionary setValue:@"type://someStuff" forKey: @"$type"];
    [requestDictionary setValue:@"account" forKey:@"Widget"];
    NSMutableDictionary* messageDictionary = [[NSMutableDictionary alloc] init];
    [messageDictionary setValue:@"type://someStuff" forKey:@"$type"];
    [messageDictionary setValue: self.password forKey:@"Password"];
    [messageDictionary setValue:false forKey:@"RememberMe"];
    [requestDictionary setValue:messageDictionary forKey:@"Message"];
    return requestDictionary;
}

然后我这样做

 NSData *postData = [NSJSONSerialization dataWithJSONObject:postDataObject
                                                           options:0 // Pass 0 if you don't care about the readability of the generated string
                                                             error: &error];

我得到了这个错误 -

Error - *** +[NSJSONSerialization dataWithJSONObject:options:error:]: Invalid top-level type in JSON write

我无法理解为什么，因为我认为我正在订阅文档中的规则 - 每个键都是一个字符串，而我只使用NSDictionary和NSString的实例。

发生了什么事？

Answer 1

设置代码块

      if ([NSJSONSerialization isValidJSONObject:postDataObject]) { NSData *postData = [NSJSONSerialization dataWithJSONObject:postDataObject
                                                       options:0 // Pass 0 if you don't care about the readability of the generated string
                                                         error: &error];}

而不是

       NSData *postData = [NSJSONSerialization dataWithJSONObject:postDataObject
                                                       options:0 // Pass 0 if you don't care about the readability of the generated string
                                                         error: &error];

使用NSJsonSerialization时出错：JSON写入中的顶级类型无效

1 个答案: