action bar navigation android code example
Example: android studio remove navigation bar
protected void onResume() {
super.onResume();
View decorView = getWindow().getDecorView();
// Hides the status and navigation bar until the user clicks
// on the screeen.
int uiOptions = View.SYSTEM_UI_FLAG_HIDE_NAVIGATION
| View.SYSTEM_UI_FLAG_FULLSCREEN;
decorView.setSystemUiVisibility(uiOptions);