How to get list value from (AsyncTask) inside other class, which is activity class..?

Question

I have a problem when I want to get the value from a global variable inside AsyncTask class. I want to call it from another class..

Here's my AsyncTask class code:

public class PlacesDisplayTask extends AsyncTask<Object, Integer, List<HashMap<String, String>>> {

    List<NearbyPlaceModel> data_place = new ArrayList<>();
    JSONObject googlePlacesJson;
    GoogleMap googleMap;

    @Override
    protected List<HashMap<String, String>> doInBackground(Object... inputObj) {

        List<HashMap<String, String>> googlePlacesList = null;
        Places placeJsonParser = new Places();

        try {
            googleMap = (GoogleMap) inputObj[0];
            googlePlacesJson = new JSONObject((String) inputObj[1]);
            googlePlacesList = placeJsonParser.parse(googlePlacesJson);
        } catch (Exception e) {
            Log.d("Exception", e.toString());
        }
        return googlePlacesList;
    }

    @Override
    protected void onPostExecute(List<HashMap<String, String>> list) {
        googleMap.clear();
        data_place.clear();
        for (int i = 0; i < list.size(); i++) {
            if(i < 10 ) {
                HashMap<String, String> googlePlace = list.get(i);
                double lat = Double.parseDouble(googlePlace.get("lat"));
                double lng = Double.parseDouble(googlePlace.get("lng"));
                String placeName = googlePlace.get("place_name");
                String vicinity = googlePlace.get("vicinity");
                LatLng latLng = new LatLng(lat, lng);
                markerOptions.icon(BitmapDescriptorFactory.fromBitmap(Configure.getBitmapFromURL(googlePlace.get("icon"))));
                markerOptions.title(placeName + " : " + vicinity);
                googleMap.addMarker(markerOptions);

                NearbyPlaceModel items = new NearbyPlaceModel();
                items.setVicinity(vicinity);
                items.setPlace_name(placeName);
                items.setLat(String.valueOf(lat));
                items.setLang(String.valueOf(lng));
                data_place.add(items);
            }
        }
    }

}

I want to set the global variable data_place = new ArrayList<>(); from another class which is my activity, like this..

ListView nearby_place = (ListView) findViewById(R.id.itemListView);
    ListAdapter customAdapter = new ListAdapter(this, R.layout.nearby_place_listview, data_place);
    nearby_place.setAdapter(customAdapter);

Or did I something wrong with my code..?

Possible duplicate of [How to get the result of OnPostExecute() to main activity because AsyncTask is a separate class?](http://stackoverflow.com/questions/12575068/how-to-get-the-result-of-onpostexecute-to-main-activity-because-asynctask-is-a) — OneCricketeer, Oct 04 '16 at 13:43

score 0 · Answer 1 · answered Oct 04 '16 at 13:31

0

If I understand it correctly! In your AsyncTask class create getter and setter method. This way you can get data_place and set data_place from your activity.

    public List<NearbyPlaceModel> getData_place() {
            return data_place;
        }

    public void setData_place(List<NearbyPlaceModel> data_place) {
            this.data_place = data_place;
        }

answered Oct 04 '16 at 13:31

Muhammed GÜNEŞ

304
2
15

yeahh i did create some method like this, but how to get from activity..? – Iam ByeBlogs Oct 04 '16 at 13:35
when you call execute method for AsyncTask? – Muhammed GÜNEŞ Oct 04 '16 at 13:38
I call execute code from other asyncTask, so i want to get directly from the last result & get from activity, example : MainActivity->AsyncTask->AsyncTask.. – Iam ByeBlogs Oct 04 '16 at 13:43
Ok. Did you try use singleton. You can keep your activiy object in singleton. Or you can keep your data_place object in singleton. http://stackoverflow.com/questions/3826905/singletons-vs-application-context-in-android – Muhammed GÜNEŞ Oct 04 '16 at 13:48

score 0 · Accepted Answer · answered Oct 04 '16 at 14:27

You can get the result by using an interface.

Create an interface with required callback method.
Implement it on your activity,
You will get the result on your callback method

Here I am giving you an example based on your code. Your MainActivity class should be like this-

 public class MainActivity extends AppCompatActivity implements PlaceInterface{

     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);

         // your code...

         // calling the AsyncTask and send reference of the interface on it
         new PlacesDisplayTask(this).execute();  // something like this

     }


     @Override
     public void myPlaceList(ArrayList<NearbyPlaceModel>   nearbyPlaceModelArrayList) {
         ListView nearby_place = (ListView)  findViewById(R.id.itemListView);
         ListAdapter customAdapter = new ListAdapter(this, R.layout.nearby_place_listview, nearbyPlaceModelArrayList);
         nearby_place.setAdapter(customAdapter);
     }
}

Your PlacesDisplayTask class should be like this-

 public class PlacesDisplayTask extends AsyncTask<Object, Integer, List<HashMap<String, String>>> {

     ArrayList<NearbyPlaceModel> data_place = new ArrayList<>();   // change
     JSONObject googlePlacesJson;
     GoogleMap googleMap;
     PlaceInterface placeInterface;    // change

     public PlacesDisplayTask(PlaceInterface placeInterface){   // change
         this.placeInterface = placeInterface;
     }

     @Override
     protected List<HashMap<String, String>> doInBackground(Object... inputObj) {

         List<HashMap<String, String>> googlePlacesList = null;
         Places placeJsonParser = new Places();

         try {
             googleMap = (GoogleMap) inputObj[0];
             googlePlacesJson = new JSONObject((String) inputObj[1]);
             googlePlacesList = placeJsonParser.parse(googlePlacesJson);
         } catch (Exception e) {
             Log.d("Exception", e.toString());
         }
         return googlePlacesList;
     }

     @Override
     protected void onPostExecute(List<HashMap<String, String>> list) {
         googleMap.clear();
         data_place.clear();
         for (int i = 0; i < list.size(); i++) {
             if(i < 10 ) {
                 HashMap<String, String> googlePlace = list.get(i);
                 double lat = Double.parseDouble(googlePlace.get("lat"));
                 double lng = Double.parseDouble(googlePlace.get("lng"));
                 String placeName = googlePlace.get("place_name");
                 String vicinity = googlePlace.get("vicinity");
                 LatLng latLng = new LatLng(lat, lng);
             markerOptions.icon(BitmapDescriptorFactory.fromBitmap(Configure.getBitmapFromURL(googlePlace.get("icon"))));
                 markerOptions.title(placeName + " : " + vicinity);
                 googleMap.addMarker(markerOptions);

                 NearbyPlaceModel items = new NearbyPlaceModel();
                 items.setVicinity(vicinity);
                 items.setPlace_name(placeName);
                 items.setLat(String.valueOf(lat));
                 items.setLang(String.valueOf(lng));
                 data_place.add(items);

                 placeInterface.myPlaceList(data_place);  // change
             }
         }
     }

 }

And this is the Interface-

 public interface PlaceInterface {
     void myPlaceList(ArrayList<NearbyPlaceModel> nearbyPlaceModelArrayList);
 }

Hope this will help you. :)

How to get list value from (AsyncTask) inside other class, which is activity class..?

2 Answers2