单元格按钮上的Swift Parse关系单击错误

Question

我正在使用tableview单元格中的按钮来创建当前登录用户与已单击的tableview单元格中显示的用户之间的关系。我已经能够为此tableview单元格按钮创建操作功能，并且可以确认由于我的日志而注册了单击，但是我的Parse保存块的else语句正在使用值nil触发。我是否试图用我的解析代码错误地建立这种关系？

TableView代码：

import UIKit

class SearchUsersRegistrationTableViewController: UITableViewController {

    var userArray : NSMutableArray = []

    override func viewDidLoad() {
        super.viewDidLoad()

        var user = PFUser.currentUser()

        loadParseData()


    }

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

    // MARK: - Table view data source

    override func numberOfSectionsInTableView(tableView: UITableView) -> Int {

        return 1

    }

    override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {

        return userArray.count

    }

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

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

        cell.addUserButton.tag = indexPath.row
        cell.addUserButton.addTarget(self, action: "addUser:", forControlEvents: .TouchUpInside)

        let users: PFObject = self.userArray.objectAtIndex(indexPath.row) as! PFObject

        if let user : PFUser = users as? PFUser {
            cell.usernameLabel.text = user.username

            println("user exist")

            if let userImage : PFFile = user["profileImage"] as? PFFile {

                userImage.getDataInBackgroundWithBlock{
                    (imageData: NSData!, error: NSError!) -> Void in

                    if error != nil {

                        let image: UIImage = UIImage(data: imageData)!

                        cell.userImage.image = image as UIImage

                    }

                }

            } else {

                cell.userImage.image = UIImage(named: "profileImagePlaceHolder")

            }

        }
        return cell
    }

    func loadParseData() {

        var query : PFQuery = PFUser.query()

        query.findObjectsInBackgroundWithBlock {
            (objects:[AnyObject]!, error:NSError!) -> Void in

            if error == nil {

                if let objects = objects {

                    println("\(objects.count) users are listed")

                    for object in objects {

                        self.userArray.addObject(object)

                    }
                    self.tableView.reloadData()
                }
            } else {
                println("There is an error")
            }
        }
    }

    @IBAction func addUser(sender: AnyObject) {

        println("Button Triggered")

        let addUserButton : UIButton = sender as! UIButton

        let user : PFObject = self.userArray.objectAtIndex(addUserButton.tag) as! PFObject

        var relation : PFRelation = PFUser.currentUser().relationForKey("Followers")

        relation.addObject(user)

        PFUser.currentUser().saveInBackgroundWithBlock {
            (succeed:Bool, error: NSError!) -> Void in
            if error != nil {

                println("Added User")

            } else {

                println(error)

            }

        }
    }

}

TableView Cell：

import UIKit

class SearchUsersRegistrationTableViewCell: UITableViewCell {



    @IBOutlet weak var userImage: UIImageView!
    @IBOutlet weak var usernameLabel: UILabel!
    @IBOutlet weak var addUserButton: UIButton!


    override func awakeFromNib() {
        super.awakeFromNib()

        userImage.layer.borderWidth = 1
        userImage.layer.masksToBounds = false
        userImage.layer.borderColor = UIColor.whiteColor().CGColor
        userImage.layer.cornerRadius = userImage.frame.width/2
        userImage.clipsToBounds = true


    }

    override func setSelected(selected: Bool, animated: Bool) {
        super.setSelected(selected, animated: animated)

        // Configure the view for the selected state
    }



}

更新：数据实际上是正确发送到解析，但我不确定为什么我的else语句被解雇。

Answer 1

if中PFUser.currentUser().saveInBackgroundWithBlock块内的addUser(...)语句看起来不对。您正在测试错误是否为!=（即出现错误）。也许如果它测试nil如下...

if error == nil {
  println("Added User")
} else {
  println(error)
}

...你会看到你期望的日志记录。