A.
启动程序AppDelegate方法按以下顺序从上至下执行
[AppDelegate applicationDidBecomeActive:]
[AppDelegate application:willFinishLaunchingWithOptions:]
[AppDelegate application:didFinishLaunchingWithOptions:]
B.
按下home键AppDelegate方法按以下顺序从上至下执行
[AppDelegate applicationWillResignActive:]
[AppDelegate applicationDidEnterBackground:]
C.
app从后台到前台AppDelegate方法按以下顺序从上至下执行
[AppDelegate applicationWillEnterForeground:]
[AppDelegate applicationDidBecomeActive:]
D.
当程序被杀掉时调动下面方法：
[AppDelegate applicationDidFinishLaunching:]
