您可能想将两者放入容器视图，可以正确地放置一个在另一个之后，而不影响超视觉真的意味着持有任意视图（虽然这可能会工作很好）。

You may want to put both into a container view, so that you can properly place one behind the other without affecting a superview not really meant to hold arbitrary views (although that will probably work just fine).