为什么在错误的单元格中添加了复选标记？

Question

我正在创建一个显示用户列表的视图。当前用户能够单击其中一个单元格，从而跟随或取消该单元格中的用户。出于某种原因，复选标记显示在不应具有复选标记的单元格中（意味着当前用户跟随某人他实际上不是）。用户的图像也不正确。我想这的原因与复选标记错误有关。我做错了什么？请帮助！

import UIKit
import Parse

class TableViewController: UITableViewController {



    var refresher: UIRefreshControl!

    var usernames = [""]
    var userIds = [""]
    var userPics = [String:PFFile]()
    var isFollowing = ["":false]


    override func viewDidLoad() {
        super.viewDidLoad()

        navigationItem.hidesBackButton = true


        refresher = UIRefreshControl()

        refresher.attributedTitle = NSAttributedString(string: "Pull to refresh")
        refresher.addTarget(self, action: "refresh", forControlEvents: UIControlEvents.ValueChanged)

        self.tableView.addSubview(refresher)
        refresh()


    }

    func refresh (){

        let query = PFUser.query()

        query?.findObjectsInBackgroundWithBlock({ (object, error) -> Void in
            if let users = object {

                self.usernames.removeAll(keepCapacity: true)
                self.userIds.removeAll(keepCapacity: true)
                self.isFollowing.removeAll(keepCapacity: true)
                self.userPics.removeAll(keepCapacity: true)

                for objects in users {
                    if let user = objects as? PFUser {


                            if user.objectId != PFUser.currentUser()?.objectId {

                                self.usernames.append(user.username!)
                                self.userIds.append(user.objectId!)

                                if let image = user["profileImage"] {
                                    self.userPics[user.objectId!] = image as? PFFile
                                }



                                let query = PFQuery(className: "Followers")
                                query.whereKey("following", equalTo: user.objectId!)
                                query.whereKey("follower", equalTo: (PFUser.currentUser()!.objectId)!)
                                query.findObjectsInBackgroundWithBlock({ (object, error) -> Void in
                                    if let object = object {

                                        if object.count > 0 {

                                            self.isFollowing[user.objectId!] = true

                                        } else {
                                            self.isFollowing[user.objectId!] = false
                                        }
                                    }
                                    if self.isFollowing.count == self.usernames.count {
                                        print(self.isFollowing)
                                        print(self.userIds)

                                        self.tableView.reloadData()
                                        self.refresher.endRefreshing()

                                    }
                                })
                            }

                        }


                    }
                }

        })

    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

    // MARK: - Table view data source

    override func numberOfSectionsInTableView(tableView: UITableView) -> Int {
        // #warning Incomplete implementation, return the number of sections
        return 1
    }

    override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        // #warning Incomplete implementation, return the number of rows
        return usernames.count
    }


    override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UsersTableViewCell {




        let cell = tableView.dequeueReusableCellWithIdentifier("Cell", forIndexPath: indexPath) as! UsersTableViewCell

        cell.userLabel.text = usernames[indexPath.row]
        if isFollowing[userIds[indexPath.row]] == true {

            cell.accessoryType = UITableViewCellAccessoryType.Checkmark
        }

        cell.userImage.frame = CGRectMake(0, 0, 100, 100)
        cell.userImage.clipsToBounds = true
        cell.userImage.layer.cornerRadius =  cell.userImage.frame.height/2

        if userPics[userIds[indexPath.row]] != nil {
            userPics[userIds[indexPath.row]]!.getDataInBackgroundWithBlock { (data, error) -> Void in
                if let data = data {
                    cell.userImage.image = UIImage(data: data)
                }
            }
        }


        return cell
    }

    override func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {

        let cell: UsersTableViewCell = tableView.cellForRowAtIndexPath(indexPath)! as! UsersTableViewCell

        if isFollowing[userIds[indexPath.row]] == false {

            isFollowing[userIds[indexPath.row]] = true


            cell.accessoryType = UITableViewCellAccessoryType.Checkmark

            let following = PFObject(className: "Followers")
            following["following"] = userIds[indexPath.row]
            following["follower"] = PFUser.currentUser()?.objectId

            following.saveInBackground()
        } else {

            isFollowing[userIds[indexPath.row]] = false

            cell.accessoryType = UITableViewCellAccessoryType.None

            let query = PFQuery(className: "Followers")
            query.whereKey("following", equalTo: userIds[indexPath.row])
            query.whereKey("follower", equalTo: (PFUser.currentUser()?.objectId)!)

            query.findObjectsInBackgroundWithBlock({ (object, error) -> Void in
                if let object = object {
                    for users in object {
                        users.deleteInBackground()
                    }
                }
            })

        }
    }

}

Answer 1

像迈克尔说的那样，你需要清除复选标记，尝试使用此代码而不是if

cell.accessoryType = isFollowing[userIds[indexPath.row]] ? UITableViewCellAccessoryType.Checkmark : UITableViewCellAccessoryType.None