- 首先定義一個(gè)類
#import@interface Person : NSObject
@property (assign, nonatomic) NSInteger age;
-(void)run;
@end
#import "Person.h"
@implementation Person
-(void)run{
NSLog(@"%s",__func__);
}
@end
- 定義分類
#import "Person.h"
@interface Person (PersonExtention)
@property (copy, nonatomic) NSString *name;
-(void)saySex;
@end
#import "Person+PersonExtention.h"
#import <objc/runtime.h>
@implementation Person (PersonExtention)
//定義常量 必須是C語(yǔ)言字符串
static char *PersonNameKey = "PersonNameKey";
-(void)setName:(NSString *)name{
/*
OBJC_ASSOCIATION_ASSIGN; //assign策略
OBJC_ASSOCIATION_COPY_NONATOMIC; //copy策略
OBJC_ASSOCIATION_RETAIN_NONATOMIC; // retain策略
OBJC_ASSOCIATION_RETAIN;
OBJC_ASSOCIATION_COPY;
*/
/*
* id object 給哪個(gè)對(duì)象的屬性賦值
const void *key 屬性對(duì)應(yīng)的key
id value 設(shè)置屬性值為value
objc_AssociationPolicy policy 使用的策略纠永，是一個(gè)枚舉值腹侣，和copy，retain撤奸，assign是一樣的吠昭，手機(jī)開(kāi)發(fā)一般都選擇NONATOMIC
objc_setAssociatedObject(id object, const void *key, id value, objc_AssociationPolicy policy);
*/
objc_setAssociatedObject(self, PersonNameKey, name, OBJC_ASSOCIATION_COPY_NONATOMIC);
}
-(NSString *)name{
return objc_getAssociatedObject(self, PersonNameKey);
}
-(void)saySex{
NSLog(@"%s----%@",__func__,self);
}
@end
總結(jié)：在分類中@property不會(huì)生成_變量喊括，也不會(huì)實(shí)現(xiàn)getter和setter方法,我們可以手動(dòng)實(shí)現(xiàn)如下
-(NSString *)name{
return @"name";
}
-(void)setName:(NSString *)name{
}
但是這樣是沒(méi)什么意義的，而且分類中不允許定義變量矢棚，所以只能用runtime類實(shí)現(xiàn)
