链接文本的颜色怎么改？

[Denial92]

label.linkTextAttributes = @{NSForegroundColorAttributeName:[UIColor redColor],NSFontAttributeName:[UIFont boldSystemFontOfSize:14]};
label.activeLinkTextAttributes = @{NSForegroundColorAttributeName:[UIColor blueColor],NSFontAttributeName:[UIFont boldSystemFontOfSize:14]};

为什么，这样写没用？