android activity 生命周期

http://tyroandroid.blogspot.com/2009/07/android-activity.html

http://www.eoeandroid.com/thread-4775-1-1.html

http://wsj.wikidot.com/android:1

http://blog.yam.com/ipray/article/29768416

http://www.eoeandroid.com/thread-58912-1-1.html

http://www.linuxgraphics.cn/android/life_circle.html

http://hi.baidu.com/1351087848313510878483/blog/item/1eef36e9424df1dfd539c98a.html

http://hxfjfk520.iteye.com/blog/1322061

http://www.cnblogs.com/cappuccino/archive/2011/07/29/2120998.html