Activity

record the note of the Activity.
1.oncreate -> onstart -> onresume->onpause-> onstop-> onrestart -> ondestroy.
you should save your data in or before onpause called.  because before onpause the process will not been killed witch the activity hosted in.
2.when the activity unvisible,it will call onpause -> onstop.
3.detroy will called after you call finish method.
4.onconfigrationchange only called when the config you set in the menifest changed .