https://qooah.com/2012/02/28/android-%e5%b9%b3%e6%9d%bf%e9%9b%bb%e8%85%a6%e5%87%ba%e8%b2%a8-1200-%e8%90%ac%e5%8f%b0-%e6%9c%aa%e9%81%94-google-%e9%a0%90%e6%9c%9f-2/