Onclick函数无法与asynctask类正确通信

Question

当我按下按钮时，它应该启动asynctask并获得json响应。我已经提供了我的java类代码和异步类代码。

此代码的行为与此类似，

当我输入优惠券代码（正确的优惠券代码）并按下按钮然后它进入捕获状态并打印异常时。当我再次按下回车按钮时，它表示成功（响应200）。之后，如果我输入无效代码并按下按钮，它仍然会显示有效代码。如果我再次使用无效代码按下按钮，则表示无效代码。

我的onclick功能有什么问题？我真的很困惑。

java class

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.cart_activity);

    couponBTN.setOnClickListener(new View.OnClickListener() {
        public void onClick(View v) {

            try {
                String CouponCode = couponET.getText().toString();
                new CouponAsyncTask(getBaseContext(), new OnTaskCompletedObject() {

                    @Override
                    public void onTaskCompletedObject(JSONObject responseJson) {

                        Constants.couponDetails = responseJson.toString();

                    }
                }).execute(CouponCode);

                loadCouponData();

                if (!Utility.isNotNull(CouponCode)) {
                    Toast.makeText(getApplicationContext(),
                            "Insert coupon code", Toast.LENGTH_LONG).show();

                } else if (status.equals("200")) {
                    Toast.makeText(getApplicationContext(),
                            "valid coupon code, processing...",
                            Toast.LENGTH_LONG).show();

                    System.out.println("valid200");


                } else {
                    Toast.makeText(getApplicationContext(),
                            "Invalid coupon code", Toast.LENGTH_LONG)
                            .show();
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    });
}

public void loadCouponData() {

    String dataCoupon = Constants.getCouponDetails();

    try {

        JSONObject dataObject = new JSONObject(dataCoupon);

        status = dataObject.optString("Status");
        discount = dataObject.optString("Discount");

    } catch (JSONException e) {
        e.printStackTrace();
    }
}

asynctask class

public class CouponAsyncTask extends AsyncTask<String, Integer, JSONObject> {
    private xxx.OnTaskCompletedObject listener;
    private static InputStream stream = null;
    private static String API;
    private JSONObject responseJson = null;
    private Context contxt;

    public CouponAsyncTask(Context baseContext, xxx.OnTaskCompletedObject onTaskCompletedObject) {

        // API = apiURL;
        this.contxt = baseContext;
        this.listener = onTaskCompletedObject;
    }

    // async task to accept string array from context array
    @Override
    protected JSONObject doInBackground(String... params) {

        String path = null;
        String response = null;
        HashMap<String, String> request = null;
        JSONObject requestJson = null;
        DefaultHttpClient httpClient = null;
        HttpPost httpPost = null;
        StringEntity requestString = null;
        ResponseHandler<String> responseHandler = null;

        Log.i("ItemCode", params[0]);

        try {

            path = "xxx";
            new URL(path);
        } catch (MalformedURLException e) {

            e.printStackTrace();
        }

        try {

            // set the API request
            request = new HashMap<String, String>();
            request.put(new String("CouponCode"), params[0]);
            request.entrySet().iterator();

            // Store locations in JSON
            requestJson = new JSONObject(request);
            httpClient = new DefaultHttpClient();
            httpPost = new HttpPost(path);
            requestString = new StringEntity(requestJson.toString());

            // sets the post request as the resulting string
            httpPost.setEntity(requestString);
            httpPost.setHeader("Content-type", "application/json");

            // Handles the response
            responseHandler = new BasicResponseHandler();
            response = httpClient.execute(httpPost, responseHandler);

            responseJson = new JSONObject(response);

        } catch (Exception e) {
            Log.e("Buffer Error", "Error converting result " + e.toString());
        }
        try {
            responseJson = new JSONObject(response);

        } catch (JSONException e) {
            Log.e("JSON Parser", "Error parsing data " + e.toString());
        }

        return responseJson;

    }

    @Override
    protected void onPostExecute(JSONObject result) {
        // TODO Auto-generated method stub
        super.onPostExecute(result);

        listener.onTaskCompletedObject(responseJson);
    }
}