'int org.ksoap2.serialization.KvmSerializable.getPropertyCount()'对空对象引用

我知道当我连接到互联网时我得到这个例外的情况，但互联网不在服务，所以我的请求到服务器的时间，但我无法处理响应...之后我得到这个例外 .

//我正在 NullPointerException on response= envelope.getResponse();

class Logintask extends AsyncTask<String, String, String> {


        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            setmainloader(1);

        }

        @Override
        protected String doInBackground(String... args) {

            String NAMESPACE = "URL";
            String URL = "API Call";
            String SOAP_ACTION = "Validate user api";
            String METHOD_NAME = "Some method";

            SoapObject Request = new SoapObject(NAMESPACE, METHOD_NAME);


            Request.addProperty("TokenID", sm.getUserDetails().get(SessionManager.TOKEN_ID));



            Request.addProperty("UserName", enteredusername);
            Request.addProperty("Pwd", enteredpassword);
            Request.addProperty("GCMID", " ");
            Request.addProperty("Imei", imei);

            SoapSerializationEnvelope envelope = new SoapSerializationEnvelope(SoapEnvelope.VER11);
            envelope.dotNet = true;
            envelope.setOutputSoapObject(Request);
            HttpTransportSE httpTransport = new HttpTransportSE(URL, 20000);

            try {
                httpTransport.call(SOAP_ACTION, envelope);

            } catch (SocketTimeoutException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            } catch (XmlPullParserException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

            try {


                //CHECK FOR RESPONSE


                Log.d("check for response", "doInBackground: ");

//我在这里得到例外????当我得到这个响应时//连接没有wifi或移动数据，但互联网没有来 .

response=envelope.getResponse();



            //  Log.d("response",response.toString());

        } catch (SoapFault e) {
            // TODO Auto-generated catch block
        }

        return null;
    }

here is my log below

致命异常：AsyncTask＃6进程：com.virtuzoconsultancyservicespvtltd.attendenceapp，PID：13903 java.lang.RuntimeException：在android.os.AsyncTask $ 3.done（AsyncTask.java：309）上执行doInBackground（）时发生错误.util.concurrent.FutureTask.finishCompletion（FutureTask.java:354）at java.util.concurrent.FutureTask.setException（FutureTask.java:223）at java.util.concurrent.FutureTask.run（FutureTask.java:242）at at android.os.AsyncTask $ SerialExecutor $ 1.run（AsyncTask.java:234）at java.util.concurrent.ThreadPoolExecutor.runWorker（ThreadPoolExecutor.java:1113）at java.util.concurrent.ThreadPoolExecutor $ Worker.run（ThreadPoolExecutor.java） ：588）at java.lang.Thread.run（Thread.java:818）引起：java.lang.NullPointerException：尝试在空对象上调用接口方法'int org.ksoap2.serialization.KvmSerializable.getPropertyCount（）'参考com.vcpl.attende上的org.ksoap2.serialization.SoapSerializationEnvelope.getResponse（SoapSerializationEnvelope.java:521） nceappnew.EmailDialog $ mailattendance.doInBackground（EmailDialog.java:224）at com.vcpl.attendenceappnew.EmailDialog $ mailattendance.doInBackground（EmailDialog.java:175）at android.os.AsyncTask $ 2.call（AsyncTask.java:295）at在java.util.concurrent.ThreadPoolExecutor.runWorker（ThreadPoolExecutor.java:1113）的android.os.AsyncTask $ SerialExecutor $ 1.run（AsyncTask.java:234）java.util.concurrent.FutureTask.run（FutureTask.java:237） ）java.lang.Thread.run上的java.util.concurrent.ThreadPoolExecutor $ Worker.run（ThreadPoolExecutor.java:588）（Thread.java:818）