HttpRequest, extend Async, Interface callback to ImageView

gistfile1.java

import com.example.streetview.HttpRequest.NetworkListener;

public class MainActivity extends Activity implements NetworkListener {

	ImageView iv;
	@Override
	public void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		iv = (ImageView) findViewById(R.id.img);
		URI uri = null;
		try {
			uri = new URI("http://maps.googleapis.com/maps/api/streetview?size=400x500&location=40.720032,%20-73.988354&sensor=false&heading=1.78");
		} catch (URISyntaxException e) {
			e.printStackTrace();
		}
		String req = uri.toASCIIString();
		HttpRequest request = new HttpRequest(this, iv);
		request.execute(req);
	}
	public void networkRequestCompleted(Bitmap streetViewPic) {
		if (streetViewPic == null) {
			return;
		}
		iv.setImageBitmap(streetViewPic);
	}
}

gistfile2.java

public class HttpRequest extends AsyncTask<String, String, Bitmap> {
	public interface NetworkListener {
		void networkRequestCompleted(Bitmap streetViewPic);
	}
	private NetworkListener _listener;
	ImageView iv;
	Bitmap bitmap;
	public HttpRequest(NetworkListener listenerParam, ImageView ivParam) {
		_listener = listenerParam;
		iv = ivParam;
	}
	@Override
	protected Bitmap doInBackground(String... uri) {
		HttpClient httpclient = new DefaultHttpClient();
		HttpResponse response;
		try {
			response = httpclient.execute(new HttpGet(uri[0]));
			StatusLine statusLine = response.getStatusLine();
			if (statusLine.getStatusCode() == HttpStatus.SC_OK) {
				bitmap = BitmapFactory.decodeStream(response.getEntity()
						.getContent());
			} else {
				response.getEntity().getContent().close();
				throw new IOException(statusLine.getReasonPhrase());
			}
		} catch (ClientProtocolException e) {
			Log.d("error:", e.getMessage());
		} catch (IOException e) {
			Log.d("error:", e.getMessage());
		}
		return bitmap;
	}
	@Override
	protected void onPostExecute(Bitmap result) {
		super.onPostExecute(result);
		if (_listener != null) {
			_listener.networkRequestCompleted(result);
			iv.setImageBitmap(bitmap);
		}
	}
}