改装，call.enqueue

Question

下面是我的代码：

retrofit2.Call<User> call = MainActivity.apiInterface.performUserLogin (username,password);
       Log.d(TAG,"retrofit");
        call.enqueue (new Callback<User> () {
            @Override
            public void onResponse( retrofit2.Call<User> call, Response<User> response )
            {
                Log.d (TAG,"in");
              if(response.body ().getResponse ().equals ("ok"))
                {
                    Log.d (TAG,"ok");
                    MainActivity.prefConfig.writeLoginStatus (true);
                    loginFormActivityLisener.performLogin (response.body ().getName ());
                }
                else if(response.body ().getResponse ().equals ("failed"))
              {
                  MainActivity.prefConfig.displayToast ("Login Failed... Please try again...");
                  Log.d(TAG,"failed");
              }

            }

            @Override
            public void onFailure( retrofit2.Call<User> call, Throwable t ) {

            }
        });

我有一个问题，为什么call.enqueue不工作？就像它不在那里一样。它什么也不做。