Why do all these duplicate items appear in the Xco

问题:

Can anyone suggest a way to prevent the following duplicates?

回答1:

Your class conforms to UITableViewDataSource and UITableViewDelegate, which declare those methods. So it might implement those methods. But it also inherits from UITableViewController, which does implement them. So your class might override those methods. Thus the method listings are arriving, as it were, from two different sources.

EDIT: Big news: this problem is resolved in Xcode 10.2.