Tag Archives: Volley

Android Volley – HTTP async Swiss Army Knife

This serves as a post to help you get started with Android Volley. Volley is used for all sorts of HTTP requests, and supports a whole bang of cool features that will make your life way easier.

It is a relatively simple API to implement, and allows request queuing, which comes in very useful.

The code below is a simple example to make a request to this blog and get a JSON response back, parse it and display it in a simple TextView widget on the device.

package za.co.paulscott.volleytest;

import org.json.JSONObject;

import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v7.app.ActionBarActivity;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;

import com.android.volley.Request;
import com.android.volley.RequestQueue;
import com.android.volley.Response;
import com.android.volley.VolleyError;
import com.android.volley.toolbox.JsonObjectRequest;
import com.android.volley.toolbox.Volley;

public class MainActivity extends ActionBarActivity {

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

        if (savedInstanceState == null) {
            getSupportFragmentManager().beginTransaction()
                    .add(R.id.container, new PlaceholderFragment())
                    .commit();
        }
        
        txtDisplay = (TextView) findViewById(R.id.txtDisplay);

		RequestQueue queue = Volley.newRequestQueue(this);
		String url = "http://paulscott.co.za/blog/wp-json.php/posts/100";

		JsonObjectRequest jsObjRequest = new JsonObjectRequest(Request.Method.GET, url, null, new Response.Listener<JSONObject>() {

			@Override
			public void onResponse(JSONObject response) {
				Log.i("volleytest",response.toString());
				String txt = response.toString();
				Log.i("volleytest", txt);
				txtDisplay.setText(txt);
				findViewById(R.id.progressBar1).setVisibility(View.GONE);
			}
		}, new Response.ErrorListener() {

			@Override
			public void onErrorResponse(VolleyError error) {
				// TODO Auto-generated method stub

			}
		});

		queue.add(jsObjRequest);
    }


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }

    /**
     * A placeholder fragment containing a simple view.
     */
    public static class PlaceholderFragment extends Fragment {

        public PlaceholderFragment() {
        }

        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                Bundle savedInstanceState) {
            View rootView = inflater.inflate(R.layout.fragment_main, container, false);
            return rootView;
        }
    }

}