- (NSString *)associatedObject_copy {
return objc_getAssociatedObject(self, _cmd);
}
- (void)setAssociatedObject_copy:(NSString *)associatedObject_copy {
objc_setAssociatedObject(self, @selector(associatedObject_copy), associatedObject_copy, OBJC_ASSOCIATION_COPY_NONATOMIC);
}上面这段代码中, _cmd 和 self 类似，只不过前者表示的是当前的SEL。
第二个方法的第二个参数为什么不也用_cmd呢？我理解的 _cmd和@selector(当前方法)不是一个意思吗？
为什么第一个方法的第二个参数用_cmd,第二个方法的第二个参数却用@selector(xxx)了啊？
希望能告知一二.....
啰嗦这么多：
其实我的问题主要是 在同一个方法里面，_cmd和@selector(当前方法) 完全一样嘛？不一样，有什么区别？
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Because to bind the same property setter and getter must be the same
key,但是用_cmd只能获取当前的方法名,所以你在set方法里面肯定要或获取跟上面相同的key,_cmd也是SEL类型的参数和@selector(xxx)sameThe second parameter of objc_getAssociatedObject and objc_setAssociatedObject is just a key
Of course, you can use @selector() as a parameter. Its essence is also a constant id. You also said above that your
_cmdis also a SEL. Logically speaking, the second parameter of your objc_setAssociatedObject should be _cmd. Generally, Usage is defined as follows:_cmd can only get the name of the current method. If you also use _cmd in set, you will get "setAssociatedObject_copy".