protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
            //透明状态栏
            getWindow().addFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_STATUS);
            //透明导航栏
            getWindow().addFlags(WindowManager.LayoutParams.FLAG_TRANSLUCENT_NAVIGATION);
        }
    }