Check nav bar

gistfile1.txt

 WindowManager mgr = (WindowManager) getSystemService(WINDOW_SERVICE);
            boolean hasSoftKey = Utils.hasSoftKeys(mgr, NPTApplication.this);

public static boolean hasSoftKeys(WindowManager windowManager, Context c) {
        boolean hasSoftwareKeys = true;

        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN_MR1) {
            Display d = windowManager.getDefaultDisplay();

            DisplayMetrics realDisplayMetrics = new DisplayMetrics();
            d.getRealMetrics(realDisplayMetrics);

            int realHeight = realDisplayMetrics.heightPixels;
            int realWidth = realDisplayMetrics.widthPixels;

            DisplayMetrics displayMetrics = new DisplayMetrics();
            d.getMetrics(displayMetrics);

            int displayHeight = displayMetrics.heightPixels;
            int displayWidth = displayMetrics.widthPixels;

            hasSoftwareKeys = (realWidth - displayWidth) > 0 || (realHeight - displayHeight) > 0;
        } else {
            boolean hasMenuKey = ViewConfiguration.get(c).hasPermanentMenuKey();
            boolean hasBackKey = KeyCharacterMap.deviceHasKey(KeyEvent.KEYCODE_BACK);
            hasSoftwareKeys = !hasMenuKey && !hasBackKey;
        }
        return hasSoftwareKeys;
    }

https://sharecoding.wordpress.com/2016/08/23/detect-navigation-bar-or-get-its-height-in-android/