Here are some functions will be call in a activity‘s life cycle:
1.oncreate():
it will be called when a activity be created.
2.onstart()
when activity be visibled.
3.onresume()
when the activity get the focus.(that‘s mean it‘s view can response u)
4.onpause
when the activity loss the focus
5.onstop
when the activity can‘t be visibled
6.ondestrory
when the activity be destroeid
Android activity‘s life cycle,布布扣,bubuko.com
原文：http://blog.csdn.net/howlaa/article/details/22694069