有哪个大神能跟我解释下 UiViewController生命周期，尽量解释的直白点。
大神们，求指导～

重写下dealloc方法就能测试

if the view not exit ->"load view " -> "view did load" -> then sent "view will appear" -> "view did appear" ->
now view can visable on scrren -> if you want remove the view -> "view will disappear" -> "view did disappear" -> if low memory warning occurs OC will call "didReceiveMerroryWarning" -> property view is received and sent to nil -> "view did unload" ...