Question

###这是整个应用程序的主要方法取决于

    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 {

                ***

citymaster = newrummy.getJSONArray（CITYARRAY）; ///面对问题这条线建议我做一些编辑 for（int i = 0; i＆lt; citymaster.length（）; i ++）{
                  newrummy = citymaster.getJSONObject(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();

            }
        }

    }

}

我的LOGCAT显示了这种异常::

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)

Answer 1

        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;

你的代码问题是你返回一个空的json对象。

更改您的代码，

newrummy=new JSONObject();至newrummy=new JSONObject(json);

在解析json数据android时会出现null响应

1 个答案: