https://qooah.com/2012/02/23/google-%e6%96%b0%e5%b0%88%e5%88%a9%e9%a1%af%e7%a4%ba-android-%e9%9b%bb%e8%85%a6%e6%88%96%e5%b0%87%e6%88%90%e7%82%ba%e7%8f%be%e5%af%a6/