To hide navigation bar for android app

WinHelper.java

/*
 * class WinHelper
*/
import android.app.Activity;
import android.view.View;
import android.view.WindowInsets;
import android.view.WindowInsetsController;

class WinHelper {
    public static void hideNavigationBar(Activity act) {
        // Get the window's decor view
        View decorView = act.getWindow().getDecorView();

        // Get the WindowInsetsController (requires API level 30+)
        WindowInsetsController controller = act.getWindow().getInsetsController();
        if (controller != null) {
            // Hide the navigation bars
            controller.hide(WindowInsets.Type.navigationBars());
            // Allow transient bars to appear on swipe gestures (optional)
            controller.setSystemBarsBehavior(WindowInsetsController.BEHAVIOR_SHOW_TRANSIENT_BARS_BY_SWIPE);
        }
    }
}