https://qooah.com/2012/09/02/android%e7%9a%84%e6%99%ba%e8%83%bd%e6%89%8b%e6%a9%9f%e8%bb%9f%e4%bb%b6%e4%bc%8a%e7%b6%ad%e5%a5%87%e8%ae%93%e4%bd%a0%e5%9c%a8%e9%a7%95%e8%bb%8a%e4%b8%ad%e4%bd%bf%e7%94%a8%e9%9b%bb%e8%a9%b1%e8%ae%8a/