swift - 使用 Swift 编辑按钮的困难

Question

我是编码世界的新手。我正在尝试合并一个编辑按钮。当用户向右滑动时，我得到了显示按钮，但我无法让编辑按钮工作。按下时，如果用户首先输入数据但信息已经放置在字段中，它应该会调出表格。

例如：用户填写艺术家、专辑和发行日期，编辑按钮应该将他们带回到他们第一次输入信息但信息已经到位的位置。

这是我用于编辑按钮的代码：

override func tableView(_ tableView: UITableView,
               leadingSwipeActionsConfigurationForRowAt indexPath: IndexPath) -> UISwipeActionsConfiguration?


{
    let modifyAction = UIContextualAction(style: .normal, title:  "Update", handler: { (ac:UIContextualAction, view:UIView, success:(Bool) -> Void) in
        print("Update action ...")
        success(true)
    })
    modifyAction.title = "Edit"
    modifyAction.backgroundColor = .blue

    return UISwipeActionsConfiguration(actions: [modifyAction])
}

这是添加内容的代码：

@IBOutlet var artisttextfield: UITextField!
@IBOutlet var albumtextfield: UITextField!
@IBOutlet var releasedatePicker: UIDatePicker!


override func viewDidLoad() {
    super.viewDidLoad()

    releasedatePicker.minimumDate = Date()

    // Do any additional setup after loading the view, typically from a nib.
}
@IBAction func saveTapped( _ sender: UIBarButtonItem) {

    let artist = artisttextfield.text ?? ""
    let album = albumtextfield.text ?? ""
    let releasedate = releasedatePicker.date

    let appDelegate = UIApplication.shared.delegate as! AppDelegate
    let context = appDelegate.persistentContainer.viewContext

    let newRelease = Release_Date(context: context)
    newRelease.artist = artist
    newRelease.album = album
    newRelease.release_date = releasedate as NSDate?
    newRelease.release_dateId = UUID().uuidString

    if let uniqueId = newRelease.release_dateId {
        print("The freshreleaseId is \(uniqueId)")
    }

    do {
        try context.save()
        let message = "\(artist)'s new album \(album) releases Today!"
        let content = UNMutableNotificationContent()
        content.body = message
        content.sound = UNNotificationSound.default()
        var dateComponents = Calendar.current.dateComponents([.month, .day],
            from: releasedate)
        dateComponents.hour = 09
        dateComponents.minute = 00
        let trigger = UNCalendarNotificationTrigger(dateMatching: dateComponents,
            repeats: true)
        if let identifier = newRelease.release_dateId {

            let request = UNNotificationRequest(identifier: identifier,
                content: content, trigger: trigger)
            let center = UNUserNotificationCenter.current()
            center.add(request, withCompletionHandler: nil)
        }
    } catch let error {
        print("Could not save because of \(error).")
    }

    dismiss(animated: true, completion: nil)

    print("Added a Release Date!")
    print("Artist: \(newRelease.artist)")
    print("Album: \(newRelease.album)")
    print("Release Date: \(newRelease.release_date)")
}

@IBAction func cancelTapped(_ sender: UIBarButtonItem) {
    dismiss(animated: true, completion: nil)
}

这是视图将出现

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

    let appDelegate = UIApplication.shared.delegate as! AppDelegate
    let context = appDelegate.persistentContainer.viewContext

    let fetchRequest = Release_Date.fetchRequest() as NSFetchRequest<Release_Date>

    let sortDescriptor1 = NSSortDescriptor(key: "album", ascending: true)
    let sortDescriptor2 = NSSortDescriptor(key: "artist", ascending: true)
    fetchRequest.sortDescriptors = [sortDescriptor1, sortDescriptor2]
    do {
        freshreleases = try context.fetch(fetchRequest)
    } catch let error {
        print("Could not fetch because of error: \(error).")
    }
    tableView.reloadData()
}

标签： swiftuitableviewedit