Android is an operating system which is based on Linux
and is open source, which is mainly used for smart mobile
devices, such as smart phones and pads. Google released the
source code of Android with the GPL [1] at November, 2007.
Because the character of open source Android is supported by a
lot of companies, so it is developping very fast, by now it is the
dominative smart phone operating system. According to IDC in
3th quarter of 2012 smart phone operating system market
Android’s share is 75% [2], and in China its share is even
higher it is 90% [3].