Question

我的聊天应用中有一个表格视图，其中包含登录到应用程序的用户。这个应用程序在Swift中，表视图嵌入在导航控制器中。我也在使用Parse。

当我点击用户时，它会将我发送到他们想要做的聊天屏幕。然后，当我单击“后退”按钮时，它会将我带回到User表视图，但是会发生一些奇怪的事情。它有登录的用户，但显示两次。例如，如果User1登录到应用程序，我单击它进行聊天，然后返回到表视图，它现在显示User1两次。如果我重复这个过程，它会显示User1三次。希望有人能帮忙......

变量：

 import UIKit

   // Global Variable 
   var userName = ""

class usersVC: UIViewController, UITableViewDataSource, UITableViewDelegate {

@IBOutlet weak var resultsTable: UITableView!

var resultsUsernameArray = [String]()
var resultsProfileNameArray = [String]()
var resultsImageFile = [PFFile]()

override func viewDidLoad() {
    super.viewDidLoad()

    let theWidth = view.frame.size.width
    let theHeight = view.frame.size.height

    resultsTable.frame = CGRectMake(0, 0, theWidth, theHeight-64)

    // PFUser.currentUser().username is part of Parse framework
    userName = PFUser.currentUser()!.username!

}

然后这里是viewDidAppear，我认为这是问题所在：

    override func viewDidAppear(animated: Bool) {

    let predicate = NSPredicate(format: "username != '"+userName+"'")
    var query = PFQuery(className: "_User", predicate: predicate)
    var theObjects = query.findObjects()
        for object in theObjects! {

        // object.username is the name of the username class in Parse, as well as "profileName" and "photo"
        self.resultsUsernameArray.append(object["username"] as! String)
        self.resultsProfileNameArray.append(object["profileName"] as! String)
        self.resultsImageFile.append(object["photo"] as! PFFile)

        self.resultsTable.reloadData()

    }



}

不确定是否需要这个但它有一些相同的变量并处理表视图：

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

    var cell : ResultsCell = tableView.dequeueReusableCellWithIdentifier("Cell") as! ResultsCell

    cell.usernameLbl.text = self.resultsUsernameArray[indexPath.row]
    cell.usernameLbl.hidden = true

    cell.profileNameLbl.text = self.resultsProfileNameArray[indexPath.row]


    resultsImageFile[indexPath.row].getDataInBackgroundWithBlock {

        (imageData: NSData?, error: NSError?) -> Void in

        if error == nil {

            let image = UIImage(data: imageData!)
            cell.profileImg.image = image
        }
    }

    return cell

}

如果需要更多代码，请告诉我们！

谢谢你，千斤顶

Answer 1

你应该像这样改变你的viewDIdAppear()方法，

override func viewDidAppear(animated: Bool) {
    let predicate = NSPredicate(format: "username != '"+userName+"'")
    var query = PFQuery(className: "_User", predicate: predicate)
    var theObjects = query.findObjects()
    self.resultsUsernameArray.removeAll(keepCapacity: true)
    self.resultsProfileNameArray.removeAll(keepCapacity: true)
    self.resultsImageFile.removeAll(keepCapacity: true)
    for object in theObjects! {

        // object.username is the name of the username class in Parse, as well as "profileName" and "photo"
        self.resultsUsernameArray.append(object["username"] as! String)
        self.resultsProfileNameArray.append(object["profileName"] as! String)
        self.resultsImageFile.append(object["photo"] as! PFFile)

        self.resultsTable.reloadData()

    }
}

HTH，享受编码!!

表格查看单元格重新加载问题

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