一、用runtime改变变量值
先看看Person类
@interface Person : NSObject
@property (nonatomic ,copy)NSString * name;
-(void)firstMethod;
-(void)secondMethod;
@end
Person类的实现
#import "Person.h"
@implementation Person
//实现第一个方法和第二个方法
-(void)firstMethod
{
NSLog(@"firstMethod");
}
-(void)secondMethod
{
NSLog(@"secondMethod");
}
@end
修改属性变量的值
-(void)changeIvar
{
///实例变量的个数
unsigned int count = 0;
///获取person中的所有的属性变量
Ivar * ivar = class_copyIvarList([self.person class], &count);
///遍历属性,去寻找到name的字段
for(int i=0;i<count;i++)
{
///获取实例变量
Ivar var = ivar[i];
const char * varName = ivar_getName(var);
///获取名字
NSString * name = [NSString stringWithUTF8String:varName];
///判断名字是不是name属性
if([name isEqualToString:@"_name"])
{
object_setIvar(self.person, var, @"Harry");
break;
}
}
NSLog(@"%@",self.person.name);
}
二、使用runtime交换方法
-(void)changeMethod
{
///获取实例方法
Method m1 = class_getInstanceMethod([self.person class], @selector(firstMethod));
Method m2 = class_getInstanceMethod([self.person class], @selector(secondMethod));
///交换
method_exchangeImplementations(m1, m2);
}
三、使用runtime添加方法
-(void)addMethod
{
class_addMethod([self.person class], @selector(run:),(IMP)runMethod , "v@:");
}
void runMethod(id self ,SEL _cmd,NSString *str)
{
NSLog(@"%@",str);
}
四、使用runtime给分类扩展属性
const char * sexStr = "key";
-(void)setSex:(NSString *)sex
{
objc_setAssociatedObject(self, &sexStr, sex, OBJC_ASSOCIATION_COPY_NONATOMIC);
}
-(NSString *)sex
{
return objc_getAssociatedObject(self, &sexStr);
}