KVO实现原理？

从被监听的类中派生出xxxxkvo_notify类 isa指针原来指向基类的, 改为指向派生类 重写setter指针 - (void)setName:(NSString *name){ xxx willchangevalueforkey:@"name" _name = name; xxx didchangevalueforkey }

>>阅读原文<<