检查复杂JSON响应中的空键

Question

我无法检查我的一个键是否为空.

以下是我正在使用的解析JSON响应:

案例1(关键'标签'不为空)

{
height = 480;
pid = "a@bsioihf93u420934";
tags =     (
            {
        attributes =             {
            mood =                 {
                confidence = 42;
                value = happy;
            };
            smiling =                 {
                confidence = 52;
                value = false;
            };
        };
        center =             {
            x = "49.86";
            y = "60.52";
        };
        confirmed = 0;
        width = "50.28";
    }
);
url = "http://abc/efg/hijk/lmnop.jpg";
width = 360;
}

有时候响应如下所示:

案例2(关键'标签'为空)

{
height = 480;
pid = "a@bsioihf93u420934";
tags =     (
);
url = "http://abc/efg/hijk/lmnop.jpg";
width = 360;
}

当我在案例2中检查'tags'是否为空时,它返回false:

if ([photo objectForKey:@"tags"] == nil)

检查[photo objectForKey:@"tags"]in log 的实际值返回:

(
) 

我怎么能检查'标签'是否为空？

Answer 1

尝试:

if ([[photo objectForKey:@"tags"] count] == 0)