https://developer.android.com/training/system-ui/immersive.html
android 4.4(kitkat) 이상
@Override protected void onResume() { super.onResume(); toggleHideyBar(); } private void toggleHideyBar() { int uiOptions = getWindow().getDecorView().getSystemUiVisibility(); int newUiOptions = uiOptions; newUiOptions ^= View.SYSTEM_UI_FLAG_HIDE_NAVIGATION; newUiOptions ^= View.SYSTEM_UI_FLAG_FULLSCREEN; newUiOptions ^= View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY; getWindow().getDecorView().setSystemUiVisibility(newUiOptions); }