ios - if(objc_getAssociatedObject(self, &Key)) 为 nil 对象返回 true

Question

如何测试 objc_getAssociatedObject 是否为 nil？下面说元素不是 nil 但关联的对象以前从未设置过也从未被访问过。

static char orderedElementKey = 11;

if (objc_getAssociatedObject(self, &orderedElementKey) != nil)
{
    NSLog(@"element is not nil");
    return objc_getAssociatedObject(self, &orderedElementKey);
}
NSLog(@"elelement was nil !");

Answer 1

static char orderedElementKey = 11;
//objc_setAssociatedObject(self, &orderedElementKey, @"value", OBJC_ASSOCIATION_RETAIN);

if (objc_getAssociatedObject(self, &orderedElementKey) != nil)
{
    NSLog(@"Element: %@", objc_getAssociatedObject(self, &orderedElementKey));
}
else
{
    NSLog(@"element nil !");
}

打印“元素为零!”在删除 objc_setAssociatedObject() 上的注释时打印“Element: value”。您的代码有何不同？