Android 分析json数据时出现空响应

###这是整个应用程序的主要方法

    private void setOnListener() {
        // TODO Auto-generated method stub
        btnGetData.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View arg0) {
                // TODO Auto-generated method stub
                new JSONParsing().execute();

            }

        });

        btnStoreData.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View arg0) {
                // TODO Auto-generated method stub
            /// System.out.println("Values of: " + cursor.getColumnCount());
                cursor = newrummydb.query(DATABASE_TABLE, new String[] {
                        cityid, cityname, createddate, isactive, stateid,
                        statename }, null,null,null,null,null);

                getfromdatabase();
            }
        });

    }

    protected void getfromdatabase()
        {



            /// Getting Data from database 

                if(cursor.moveToFirst())
                {
                    do
                    {

                tvCity_ID.setText(cursor.getString(0));
                tvCityName.setText(cursor.getString(1));
                tvCreatedDate.setText(cursor.getString(2));
                tvIsActive.setText(cursor.getString(3));
                tvState_ID.setText(cursor.getString(4));
                tvStateName.setText(cursor.getString(5));
                tvUpdatedDate.setText(cursor.getString(6));
                    }
                    while (cursor.moveToNext());


                }
        mydb.close();
        }

    protected class JSONParsing extends AsyncTask<String, String, JSONObject> {
        private ProgressDialog progressdialog;

        @Override
        protected void onPreExecute() {
            super.onPreExecute();
            progressdialog = new ProgressDialog(NewRummyActivity.this);

            progressdialog.setMessage("Retrieving Data...");
            progressdialog.setCancelable(true);
            progressdialog.show();

        }

        @Override
        protected JSONObject doInBackground(String... params) {
            // TODO Auto-generated method stub
            RummyJSONParser jsonparsing = new RummyJSONParser();
            JSONObject newrummy = jsonparsing.getJSONFromURL(url);

            return newrummy;
        }

        @Override
        protected void onPostExecute(JSONObject newrummy) {
            progressdialog.dismiss();

            try {

                ***

---

我的LOGCAT显示这种异常：：

04-15 19:06:36.713: I/System.out(28523): Values are:null
04-15 19:06:36.845: W/System.err(28523): org.json.JSONException: No value for cityMasterEntity
04-15 19:06:36.845: W/System.err(28523):    at org.json.JSONObject.get(JSONObject.java:354)
04-15 19:06:36.845: W/System.err(28523):    at org.json.JSONObject.getJSONArray(JSONObject.java:544)
04-15 19:06:36.845: W/System.err(28523):    at com.example.newrummyjson.NewRummyActivity$JSONParsing.onPostExecute(NewRummyActivity.java:168)
04-15 19:06:36.845: W/System.err(28523):    at com.example.newrummyjson.NewRummyActivity$JSONParsing.onPostExecute(NewRummyActivity.java:1)
04-15 19:06:36.845: W/System.err(28523):    at android.os.AsyncTask.finish(AsyncTask.java:631)

代码的问题在于，您返回的是一个空的json对象

将您的代码从

---

newrummy=newjsonobject（）

to

newrummy=newjsonobject（json）

String\u response=EntityUtils.toString（entity）

getJSONFromURL中的return\u response@bluefeet请删除此问题此块是否显示空指针异常：：建议一些帮助citymaster=newrummy.getJSONArray（CITYARRAY）；对于（int i=0；i // data.set_ID(Integer.parseInt(newrummy.getString(DFID))); values.put("_id", i + 1); cityid = newrummy.getJSONArray(cityid).getString(i); values.put("city", cityid); cityname = newrummy.getJSONArray(cityname).getString(i); values.put("cityname", cityname); createddate = newrummy.getJSONArray(createddate).getString(i); values.put("cityname", createddate); isactive = newrummy.getJSONArray(isactive).getString(i); values.put("ground", isactive); stateid = newrummy.getJSONArray(stateid).getString(i); values.put("stateid", stateid); statename = newrummy.getJSONArray(statename).getString(i); values.put("statename", statename); updateddate = newrummy.getJSONArray(updateddate).getString(i); values.put("updateddate", updateddate); newrummydb.insert(DATABASE_TABLE, null, values); } final CustomAdapter adapter = new CustomAdapter( NewRummyActivity.this, R.layout.newrummylistitem, cursor); newrummydatalist.setAdapter(adapter); adapter.notifyDataSetChanged(); } catch (JSONException e) { // TODO Auto-generated catch block e.printStackTrace(); } } } }

04-15 19:06:36.713: I/System.out(28523): Values are:null
04-15 19:06:36.845: W/System.err(28523): org.json.JSONException: No value for cityMasterEntity
04-15 19:06:36.845: W/System.err(28523):    at org.json.JSONObject.get(JSONObject.java:354)
04-15 19:06:36.845: W/System.err(28523):    at org.json.JSONObject.getJSONArray(JSONObject.java:544)
04-15 19:06:36.845: W/System.err(28523):    at com.example.newrummyjson.NewRummyActivity$JSONParsing.onPostExecute(NewRummyActivity.java:168)
04-15 19:06:36.845: W/System.err(28523):    at com.example.newrummyjson.NewRummyActivity$JSONParsing.onPostExecute(NewRummyActivity.java:1)
04-15 19:06:36.845: W/System.err(28523):    at android.os.AsyncTask.finish(AsyncTask.java:631)

        json=sb.toString();
        System.out.println("Values are:" +sb);
        newrummy=new JSONObject(); //problem lies here

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

    return newrummy;