如图
- (void)viewDidLoad {
[super viewDidLoad];
//定义一个 Person 类, 继承自 NSObject
Class Person = objc_allocateClassPair([NSObject class], "Person", 0);
//添加属性
objc_property_attribute_t type = { "T", "@\"NSString\"" };
objc_property_attribute_t ownership = { "C", "" }; // C = copy
objc_property_attribute_t backingivar = { "V", "_privateName" };
objc_property_attribute_t attrs[] = { type, ownership, backingivar };
class_addProperty(Person, "name", attrs, 3);
//添加方法
class_addMethod(Person, @selector(name), (IMP)nameGetter, "@@:");
class_addMethod(Person, @selector(setName:), (IMP)nameSetter, "v@:@");
//注册该类
objc_registerClassPair(Person);
//获取实例
id instance = [[Person alloc] init];
NSLog(@"%@", instance);
[instance setName:@"hxn"];
NSLog(@"%@", [instance name]);
}
//get方法
NSString *nameGetter(id self, SEL _cmd) {
Ivar ivar = class_getInstanceVariable([self class], "_privateName");
return object_getIvar(self, ivar);
}
//set方法
void nameSetter(id self, SEL _cmd, NSString *newName) {
Ivar ivar = class_getInstanceVariable([self class], "_privateName");
id oldName = object_getIvar(self, ivar);
if (oldName != newName) object_setIvar(self, ivar, [newName copy]);
}
