1：如果无法保证子类行为的一致性，那么就用委托
If the subClass cann't keep with superClass,use delegate rather than inheritance.
2:屏幕上看到的，都是UIVew
Everything you see on Screen is UIView.
3:如果对性能要求高，慎用Interface Build
if application's performance is important,be discreet for the interface build.
4:copy是创建，retain是引用
the copy operation is create a new one,but the retain operation is just a reference.
5：alloc需要release,convenient不需要release
alloc method need corresponding release method,but convenient method not.
6:加载到NSArray/NSMutableArray里的对象，不需要负责release
The objects added to NSArray/NSMutableArray need not to be released.
7:IBOutlet,IBAction为你开启了访问Interface Build中对象的大门
IBOutlet and IBAction open the door to access the objects in Interface build.
8:UIApplicationDelegate负责应用程序的生命周期，而UIViewController负责View的生命周期
UIApplicationDelegate is responsible for the application life cycle,but UIViewController for the UIView.
9:为了程序的健壮性，请尽量实现Delegate的生命周期函数
if you want to develop a robust application,implement the life cycle methods as more as possbile.
10:哥触摸的不是UIEvent,而是NSSet的UIView
what you touch on screen is not UIEvent but UIView