访问和修改类的私有属性由一下两种方法实现:
1.通过KVC获取
2.通过runtime访问并修改
定义Person类:
.h文件
#import <Foundation/Foundation.h>
@interface Person : NSObject
@property (nonatomic, strong) NSString *name;
-(void)sayHello;
@end
.m文件
#import "Person.h"
@interface Person()
@property (nonatomic,strong) NSString *address;
@end
@implementation Person
-(instancetype)init{
self = [super init];
if (self) {
_address = @"三里屯";
self.name = @"张晓";
}
return self;
}
- (NSString *)description
{
return [NSString stringWithFormat:@"我的名字是: %@, 居住在: %@",self.name, self.address];
}
-(void)sayHello{
NSLog(@"hello ,I'm at %@",self.address);
}
@end
方法一:KVC(键值编码):
Person *onePerson = [[Person alloc]init];
NSLog(@"未修改前: %@",onePerson.description);
[onePerson setValue:@"西二旗" forKey:@"address"];
NSLog(@"通过KVO修改私有属性后:%@",[onePerson description]);
打印结果:
2017-02-14 17:30:43.877 chermon[11436:190372] 未修改前: 我的名字是: 张晓, 居住在: 三里屯
2017-02-14 17:30:43.878 chermon[11436:190372] 通过KVO修改私有属性后:我的名字是: 张晓, 居住在: 西二旗
方法二: 通过runtime:
Person *onePerson = [[Person alloc]init];
NSLog(@"未修改前: %@",onePerson.description);
unsigned int count = 0;
//获取指定类的Ivar列表及Ivar个数
Ivar *member = class_copyIvarList([Person class], &count);
for(int i = 0; i < count; i++){
Ivar var = member[i];
//获取Ivar的名称
const char *memberAddress = ivar_getName(var);
//获取Ivar的类型
const char *memberType = ivar_getTypeEncoding(var);
NSLog(@"address = %s ; type = %s",memberAddress,memberType);
}
//设置实例对象中Ivar的值
object_setIvar(onePerson, member[1], @"海淀区");
NSLog(@"通过runtime修改私有属性后:%@",[onePerson description]);
打印结果:
2017-02-14 17:34:46.388 chermon[11487:193486] 未修改前: 我的名字是: 张晓, 居住在: 三里屯
2017-02-14 17:34:46.389 chermon[11487:193486] address = _name ; type = @"NSString"
2017-02-14 17:34:46.389 chermon[11487:193486] address = _address ; type = @"NSString"
2017-02-14 17:34:46.389 chermon[11487:193486] 通过runtime修改私有属性后:我的名字是: 张晓, 居住在: 海淀区