iOS中的JSON錯誤：JSON寫入中的頂級類型無效

Question

我無法解決這個錯誤：

*** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '*** +[NSJSONSerialization writeJSONObject:toStream:options:error:]: Invalid top-level type in JSON write'

這涉及到這一塊代碼（基本上我正在創建一些JSON並將其發送到服務器）。 我已經檢查過服務器以查看套接字是否已打開，它是什么！

NSDictionary *blobData = [NSDictionary dictionaryWithObjectsAndKeys:
                          sendString,@"string",
                          nil];
NSString *blobString = [[NSString alloc]
                        initWithData:[NSJSONSerialization dataWithJSONObject:blobData options:kNilOptions error:&error]
                        encoding:NSUTF8StringEncoding];
NSLog(@"Blob Created: %@", blobString);
NSDictionary *requestData = [NSDictionary dictionaryWithObjectsAndKeys:
                             @"send_string",@"request_type",
                             [NSNumber numberWithInt:0],@"security_level",
                             @"ios",@"device_type",
                             //No Email Provided, This is just for testing
                             blobData,@"blob",
                             nil];

NSData *JSONRequestData = NULL;
if ([NSJSONSerialization isValidJSONObject:requestData]) {
    NSLog(@"Proper JSON Object");
    JSONRequestData = [NSJSONSerialization dataWithJSONObject:requestData options:kNilOptions error:&error];
}
else {
    NSLog(@"requestData was not a proper JSON object");
    return FALSE;
}
NSLog(@"Error:%@",[[error userInfo] objectForKey:@"NSDebugDescription"]);
NSLog(@"Contents of JSONRequestData: %@",[[NSString alloc] initWithData:JSONRequestData encoding:NSUTF8StringEncoding]);
[NSJSONSerialization writeJSONObject:JSONRequestData toStream:outputStream options:0 error:&error];

我是否錯誤地創建了JSON對象？ 也許我處理“blob”的方式有問題

這是我創建JSONRequestData后NSLogs打印的內容

{"security_level":"0","request_type":"send_string","device_type":"ios","blob":{"string":"hello"}}

Answer 1

writeJSONObject期望您要發送的實際反序列化對象，因此在這種情況下，您需要將requestData對象傳遞給它，而不是像JSONRequestData那樣：

NSJSONSerialization writeJSONObject:requestData toStream:outputStream options:0 error:&error];