iOS - 类别和扩展（Categories和Extensions）

1 #import “UIViewController.h”
2 @interface UIViewController（CustomView）
3 -（void）extMethod；
4 @end

1 #import “UIViewController+CustomView.h”
2 @implementation UIViewController（CustomView）
3 -（void）extMethod；
4 @end

1 @interface MyObject:NSObject
 2 {
 3 NSNumber* number;
 4 }
 5 -(NSNumber*)getNum;
 6 @end
 7  
 8 @interface MyObject(Setter)
 9 -(void)setNum:(NSNumber*)num;
10 @end
11  
12 @implementation MyObject
13 -(NSNumber*)getNum
14 {
15 return number;
16 }

1 @interface MyObject:NSObject
 2 {
 3 NSNumber* number;
 4 }
 5 -(NSNumber*)getNum;
 6 @end
 7  
 8 @interface MyObject() //注意这里的括号里面是没有名字的
 9 -(void)setNum:(NSNumber*)num;
10 @end
11  
12 @implementation MyObject
13 -(NSNumber*)getNum
14 {
15 return number;
16 }
17  
18 -(void)setNum:(NSNumber*)num
19 {
20 number = num;
21 }
22 @end