https://qooah.com/2011/07/08/google-%e5%b0%87%e6%8e%a8%e5%87%ba-android-2-3-5%e5%a4%a9%e6%9b%b4%e6%96%b0-%e5%8f%af%e6%83%9c%e8%b7%9f%e6%88%91%e5%80%91%e7%84%a1%e9%97%9c/