我一直在我的应用程序中使用排球。我已经在5.0.2版本的设备中测试了我的应用程序，它会抛出异常，如..
05-15 14:56:02.374: E/Volley(23574): [18922] BasicNetwork.performRequest: Unexpected response code 200 for http://sample_url.com (sample url)
05-15 14:56:02.380: E/AndroidRuntime(23574): FATAL EXCEPTION: Thread-18922
05-15 14:56:02.380: E/AndroidRuntime(23574): Process: com.example.jadoofy_android, PID: 23574
05-15 14:56:02.380: E/AndroidRuntime(23574): java.lang.NullPointerException: Attempt to read from field 'int com.android.volley.NetworkResponse.statusCode' on a null object reference
05-15 14:56:02.380: E/AndroidRuntime(23574): at com.android.jadhoofy.backend_tracker_volley.BackEndHelper_volley$3.parseNetworkError(BackEndHelper_volley.java:480)
05-15 14:56:02.380: E/AndroidRuntime(23574): at com.android.volley.NetworkDispatcher.parseAndDeliverNetworkError(NetworkDispatcher.java:149)
05-15 14:56:02.380: E/AndroidRuntime(23574): at com.android.volley.NetworkDispatcher.run(NetworkDispatcher.java:138)
响应代码200被视为错误响应。但它在所有其他版本中都可以正常工作