How To Play Video In Full Screen

how t play video in full-Screen android. my video play but not in fullScreen.

here is my code;

MainActivity.java
--------------------

public
class MainActivity extends Activity {

@Override
publicvoid onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
VideoView vd = (VideoView) findViewById(R.id.VideoView);
MediaController mediaController = new MediaController(this);

[Code]....