https://qooah.com/2011/03/16/%e5%91%8a%e5%88%a5%e5%ad%a4%e5%85%92-milestone-android-2-2-%e6%9b%b4%e6%96%b0-%e8%ae%93%e6%ad%90%e6%b4%b2%e5%85%88%e8%a1%8c/