AFNetworking 2.0 - 使用responseObject作为NSDictionary

AFHTTPRequestOperationManager *manager = [AFHTTPRequestOperationManager manager];
[manager GET:@"http://example.com/resources.json" parameters:nil success:^(AFHTTPRequestOperation *operation, id responseObject) {
    NSLog(@"JSON: %@", responseObject);
} failure:^(AFHTTPRequestOperation *operation, NSError *error) {
    NSLog(@"Error: %@", error);
}];

这是推荐方式 https://github.com/AFNetworking/AFNetworking#get-request发送GETAFNetworking 2.0 中的请求。我想获取json中特定键的值，所以我想使用responseObject as NSDictionary。这就是我正在尝试的：

NSError *jsonError = nil;
NSDictionary *json = [NSJSONSerialization JSONObjectWithData:(NSData *)responseObject options:kNilOptions error:&jsonError];

它不起作用：

 *** Terminating app due to uncaught exception 'NSInvalidArgumentException', reason: '-[__NSCFDictionary bytes]: unrecognized selector sent to instance 0xa048120'

我怎样才能获得特定键的值responseObject?

默认情况下，AFHTTPRequestOperationManager sets responseSerializer to an AFJSONResponseSerializer实例，所以responseObject已经是你解析的 JSON （在你的情况下，它将是一个NSDictionary按照你说的）。

然后，就像使用字典一样使用它：

NSString *value = responseObject[@"someKey"];