斯坦福ios7 lecture4 要点

1.Creating Objects

有时候class creator和init method同时存在

Class creator method:[NSString stringWithFormat:...]

Init method:[NSString alloc] init]

苹果公司倾向使用后者

2.you can ask other Objects to create new object s for you

3.but not all Objects given out by other Objects are newly created

4.Sending messages to nil is mostly OK.

5.all object pointers are treated like id at runtime.

Dynamic binding:

6.Static typing

7.never use id *

8.casting

9.Introspection内省

10.Protocols

Does not specify the class of an object pointed to,  but  does specify what methods it implements.

In between id and static typing