Bind spinner to dynamic list

Question

I am trying to bind a list coming from .net web-service. I am able to fetch list from webservice. But I am not able to bind list to spinner.

private class AsyncCallWS extends AsyncTask<String, Void, Void> {

    private LayoutInflater mInflater;
    private List<ValueText> lstRegions;
    private Activity activity;
    private String strRegions;


    AsyncCallWS() {
        lstRegions = new LinkedList<ValueText>();
    }
    @Override
    protected Void doInBackground(String... params) {
        //Invoke webservice
        try {
            strRegions = WebService.invokeSelectRegionMasterWS("SelectRegionMaster");
            String[] regions = strRegions.split("\\},\\{");
            int i =0;
            for (String s: regions) {
                String strid = "", strName="";
                //logic to add data to list
            }




                Spinner spnDivision = (Spinner)findViewById(R.id.spnDivision);
                MySpinnerAdapter adptRegion =
                        new MySpinnerAdapter(MyActivity.this,
                                android.R.layout.simple_spinner_item, lstRegions);



        } catch (Exception e) {
            Log.e("myException", e.getMessage());
        }
        return null;
    }
}

So i can call MySpinnerAdapter from here, but I cannot use setadapter since this is working thread. doInBackground method has to be Void. So is there any way I can return the list? Or I can store list in something like viewstate (viewstate is asp.net). I am very new to Java and Android. And I really have no clue how to move forward. Please help.

score 2 · Accepted Answer · edited May 23 '17 at 10:32

You can create callback that will return data from web service, after that in your activity you can set this data to adapter and attach it to spinner.

Example:

AsyncCallWS.class

public class AsyncCallWS extends AsyncTask<String, Void, List<String>> {
    @NonNull
    private OnTaskCompleteCallback callback;

    public AsyncCallWS(@NonNull OnTaskCompleteCallback callback) {
        this.callback = callback;
    }

    @Override
    protected List<String> doInBackground(String... params) {
        try {
            //fetch data from web service
            List<String> result = new ArrayList<>();
            for (int i = 0; i < 10; i++) {
                //here you can add all needed values which will be used in spinner
                result.add("Item " + i);
            }
            return result;
        } catch (Exception e) {
            return Collections.emptyList();
        }
    }

    @Override
    protected void onPostExecute(List<String> strings) {
        super.onPostExecute(strings);
        callback.dataReady(strings);
    }

    public interface OnTaskCompleteCallback {
        void dataReady(@NonNull List<String> data);
    }
}

MainActivity.class

import android.os.Bundle;
import android.support.annotation.NonNull;
import android.support.v7.app.AppCompatActivity;

import java.util.List;


public class MainActivity extends AppCompatActivity implements AsyncCallWS.OnTaskCompleteCallback {
 @Override
 protected void onCreate(Bundle savedInstanceState) {
  super.onCreate(savedInstanceState);
  setContentView(R.layout.activity_main);
  AsyncCallWS callWS = new AsyncCallWS(this);
  callWS.execute("some_params");
 }

 @Override
 public void dataReady(@NonNull List < String > data) {
  //here you can set data in adapter
 }
}

Btw take a look into RxJava, using this approach you can easily make async task with few lines of code. If you interested in this I can add example with using RxJava

score 1 · Answer 2 · answered Oct 22 '16 at 17:08

1

You can declare static variable globally and store list in that variable and after post execute you can use that variable and bind value in spinner.

answered Oct 22 '16 at 17:08

MIkka Marmik

1,101
11
29

Bind spinner to dynamic list

2 Answers2