ios - PFObject 没有成员 objectforkey

Question

这是我的代码:

override func viewWillAppear(animated: Bool) {
    super.viewWillAppear(animated)

    state = .DefaultMode

    // fill the cache of a user's followees
    ParseHelper.getFollowingUsersForUser(PFUser.currentUser()!) { (results: [PFObject]?, error: NSError?) -> Void in
        let relations = results
        // use map to extract the User from a Follow object
        self.followingUsers = relations.map {
            $0.objectForKey(ParseHelper.ParseFollowToUser) as! PFUser
        }
    }
}

我的错误:

Value of type '[PFObject]' has no member 'objectForKey'

Answer 1

我猜是因为 [PFObjects] 数组是可选的并且尚未解包。

if let relations = results {
    // use map to extract the User from a Follow object
    self.followingUsers = relations.map {
        $0.objectForKey(ParseHelper.ParseFollowToUser) as! PFUser
    }
}