https://qooah.com/2011/04/24/%e5%b9%b3%e7%ad%89%e5%be%85%e9%81%87-%e7%be%8e%e5%9c%8b%e5%ae%98%e6%96%b9apps-%e4%b9%9f%e6%9c%89-android-%e7%9a%84%e4%bb%bd%e5%85%92/