hideAndShowAndroidSystemsBar.java

    // This snippet hides the system bars.
    private void hideSystemUI() {
        // Set the IMMERSIVE flag.
        // Set the content to appear under the system bars so that the content
        // doesn't resize when the system bars hide and show.
        View mDecorView = getWindow().getDecorView();
        mDecorView.setSystemUiVisibility(
                View.SYSTEM_UI_FLAG_LAYOUT_STABLE
                        | View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
                        | View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN
                        | View.SYSTEM_UI_FLAG_HIDE_NAVIGATION // hide nav bar
                        | View.SYSTEM_UI_FLAG_FULLSCREEN // hide status bar
                        | View.SYSTEM_UI_FLAG_IMMERSIVE);
    }

    // This snippet shows the system bars. It does this by removing all the flags
// except for the ones that make the content appear under the system bars.

    private void showSystemUI() {
        View mDecorView = getWindow().getDecorView();
        mDecorView.setSystemUiVisibility(
                View.SYSTEM_UI_FLAG_LAYOUT_STABLE
                        | View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION
                        | View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN);
    }