0912-从启动iOS的app的生命周期说起，Responding to the Launch of Your App必须清楚的前提知识点：
必须清楚的前提知识点：1、All apps have an associated process, represented by the UIApplication object. 进程对应 ---每一个app在ios系统中都有一个进程对应，而在这个进程就是用UIApplication object来表征。 --whose job is to respo...
