https://qooah.com/2012/05/12/google-%e5%80%9f%e9%91%91-apple-game-center%ef%bc%8c%e6%ba%96%e5%82%99%e6%8e%a8%e5%87%ba%e8%87%aa%e5%ae%b6%e9%81%8a%e6%88%b2%e5%b9%b3%e5%8f%b0%ef%bc%9f/