Question

I am trying to pass a string array to my adapter. My problem is i initialized globally and try to create string array in my asynchronous task below. But i am getting as null. Below is my code. Actually in this example they taking it from resource folders bu i want it from my json response. Any help is appreciated.

        String[] mString;
        public ActionsAdapter(Context context) {
             mInflater = LayoutInflater.from(context);
             session = new SessionManager(context);
             final Resources res = context.getResources();
             new ConnectAppMenu(context).execute();
             //  mTitles = res.getStringArray(R.array.actions_names);
            //  mUrls = res.getStringArray(R.array.actions_links);
            //  mIcons = res.obtainTypedArray(R.array.actions_icons);
             System.out.println("Menus"+ mString);

         }
         public class ConnectAppMenu extends AsyncTask<String, Void, String> {
    private ProgressDialog dialog;
    private final Context context;
    public ConnectAppMenu(Context context) {
        this.context = context;
    }
     @Override
        protected void onPreExecute() {
        // UI work allowed here
        dialog = new ProgressDialog(context);
        // setup your dialog here
        dialog.setMessage("Connecting....");
        dialog.setCancelable(false);
        dialog.show();
        }
    @Override
    protected String doInBackground(String... params) {
        String returnConnect = doConnectAppMenu();
        return returnConnect;
    }      
    public String doConnectAppMenu() {
        HashMap<String, String> user = session.getUserDetails();
        String client_url = user.get(SessionManager.KEY_CLIENT);
    //  if(connection) {
            HttpParams connectionParameters =  new BasicHttpParams(); 
            int timeoutConnection = 8000;
            HttpConnectionParams.setConnectionTimeout(connectionParameters, timeoutConnection);                 
            int timeoutSocket = 10000;
            HttpConnectionParams.setSoTimeout(connectionParameters, timeoutSocket);
            HttpClient httpClient   =   new DefaultHttpClient(connectionParameters);
            HttpPost httpPost       =   new HttpPost(client_url+"/api/common/app_menu");
            JSONObject json = new JSONObject();    
          try{
            json.put("data", 1);
             json.put("versionid", 1);                          
             StringEntity se = new StringEntity(json.toString());
             se.setContentType(new BasicHeader(HTTP.CONTENT_TYPE, "application/json"));
             httpPost.setEntity(se);                       
             //Execute HTTP post request
             appmenu_res    =   httpClient.execute(httpPost); 
             appmenu_obj = new org.json.JSONObject(org.apache.http.util.EntityUtils.toString(appmenu_res.getEntity()));
             appmenu_result = appmenu_obj.toString();

           }
            catch(JSONException ex) {
                // TODO Auto-generated catch block
                ex.printStackTrace();
            } catch (ClientProtocolException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
//  }           
        return appmenu_result;
    }
    @Override
    public void onPostExecute(String result) {

        int status_code = appmenu_res.getStatusLine().getStatusCode();                          
            if (status_code == 200) {
                dialog.dismiss();

                try {
                    menuObject = new JSONObject(result);
                    JSONArray names= menuObject.names();
                    JSONArray values = menuObject.toJSONArray(names);
                        for (int i = 0; i< values.length(); i++) {

                            JSONObject json2 = (JSONObject) values.get(i);
                            int menu_id = json2.getInt("menu_id");

                              if (menu_id > 0) {

                                  if (json2.has("menu_name")) {
                                     menu_list = json2.get("menu_name").toString();
                                     mString = new String[] { menu_list };

                                     //mUrls = menu_list.length();
                                  }

                              } 
                }
                        System.out.println("Json Menu" + Arrays.toString(mString));

                    /*Iterator<String> iter = menuObject.keys();
                    while (iter.hasNext()) {
                        String key = iter.next();
                        try {
                            Object value = menuObject.get(key);
                            //System.out.println("Hai" +value);
                            System.out.println("Post Execute" +  value);

                        } catch (JSONException e) {
                            // Something went wrong!
                        }
                    }*/
                } catch (JSONException e) { 
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
                //dialog.dismiss();

            }
    }

}

Answer 1

well first of all if you’re looking for the JSON object as a String don’t do what you did here:

appmenu_obj = new org.json.JSONObject(org.apache.http.util.EntityUtils.toString(appmenu_res.getEntity()));

I’d suggest doing the following:

String Json = EntityUtils.toString(appmenu_res.getEntity());
return Json;

Now if you want to do the processing of your JSON on the UI thread (as you seem to want to based on the return type being a string) this should work. However this method is not recommended since the Json will need to be processed into objects which will take time and clog the UI thread.

A better solution would be to serialize your Json on the background thread and then pass the serialized object back to the main thread to update the UI.

If you have many types I would suggest using generics. I’ve already built a Loader which can do what you want if you want here. You will need touse the GSON library and build appropriate seralizers. Also working with the loader class is different to working with the AsyncTaskClass so please read the documentation here

Edit

Ok so what you want to do if you want get the Activity to have a callback from the AsyncTask is to do something along the lines of:

public class MyActivity extends Activity implements AsyncTaskCallback

where AsyncTaskCallback looks something like :

public interface AsyncTaskCallback
{
    public processData(Object responseObject);
}

now in your onPostExecute code you’ll need to do somehting like:

@Override
protected void onPostExecute(Object r){
    if (r != null) {
       l.processData(data);
    }
}

and add the following function to your async task

public void addAsyncTaskListener (final AsyncTaskListener l){
    mCallback = l;
}

and then finally add the listner and process the data as required in the Activity in the function processData function that the interface forces your activity to implement.