Programmatically make app FULL SCREEN in Android

add this in Activity onCreate before setContentView:

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    // remove title
    requestWindowFeature(Window.FEATURE_NO_TITLE);
    getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
        WindowManager.LayoutParams.FLAG_FULLSCREEN);
    setContentView(R.layout.main);
}

and in AndroidManifest.xml file:

<activity android:name=".ActivityName"
    android:label="@string/app_name"
    android:theme="@android:style/Theme.NoTitleBar.Fullscreen">
</activity>

You can create new style and add

<item name="android:windowFullscreen">true</item>

Or you can do it programmatically:

getWindow().addFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN);

add two lines...

requestWindowFeature(Window.FEATURE_NO_TITLE); 
this.getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
setContentView(R.layout.main);