删除单元格前警告控制器 Swift Xcode

Question

我想知道如何在删除单元格之前显示删除确认（警告）。单元格是带有信息的字符，因此如果用户错误地删除（滑动）一个单元格会很糟糕。

这是允许我删除我的行的片段。我正在使用 Xcode 10 / Swift

// Delete Rows
override func tableView(_ tableView: UITableView,
               trailingSwipeActionsConfigurationForRowAt indexPath: IndexPath) -> UISwipeActionsConfiguration?
{
    let modifyAction = UIContextualAction(style: .normal, title:  "Delete", handler: { (ac:UIContextualAction, view:UIView, success:(Bool) -> Void) in
        print("Update action ...")
        success(true)

        self.namesArray.remove(at: indexPath.row)
        self.imagesArray.remove(at: indexPath.row)

        self.tableView.deleteRows(at: [indexPath], with: .fade)

    })
    modifyAction.image = UIImage(named: "delete")
    modifyAction.backgroundColor = .purple

    return UISwipeActionsConfiguration(actions: [modifyAction])

}

Answer 1

你可以试试

override func tableView(_ tableView: UITableView,
               trailingSwipeActionsConfigurationForRowAt indexPath: IndexPath) -> UISwipeActionsConfiguration?
{
    let modifyAction = UIContextualAction(style: .normal, title:  "Delete", handler: { (ac:UIContextualAction, view:UIView, success:(Bool) -> Void) in
        print("Update action ...")
        success(true)

         let alertView = UIAlertController(title: "", message: "Are you sure you want to delete the item ? ", preferredStyle: .alert)
         let okAction = UIAlertAction(title: "OK", style: .default, handler: { (alert) in
             self.namesArray.remove(at: indexPath.row)
             self.imagesArray.remove(at: indexPath.row)     
             self.tableView.deleteRows(at: [indexPath], with: .fade)
        })
        let cancelAction = UIAlertAction(title: "Cancel", style:.cancel, handler: { (alert) in
             print("Cancel")
        })
        alertView.addAction(okAction)
        alertView.addAction(cancelAction)
        self.present(alertView, animated: true, completion: nil)

    })
    modifyAction.image = UIImage(named: "delete")
    modifyAction.backgroundColor = .purple 
    return UISwipeActionsConfiguration(actions: [modifyAction])

}

Answer 2

您可以将显示 UIAlertController 的代码提取到一个单独的方法中，您可以在用户按下删除键时调用该方法。这是下面的代码，确保闭包中包含的所有表示逻辑都被分派到主线程。

func tableView(_ tableView: UITableView, trailingSwipeActionsConfigurationForRowAt indexPath: IndexPath) -> UISwipeActionsConfiguration? {
    let modifyAction = UIContextualAction(style: .normal, title:  "Delete", handler: { (ac:UIContextualAction, view:UIView, success:(Bool) -> Void) in
        DispatchQueue.main.async {
            self.showDeleteWarning(for: indexPath)
        }

        success(true)
    })

    modifyAction.image = UIImage(named: "delete")
    modifyAction.backgroundColor = .purple

    return UISwipeActionsConfiguration(actions: [modifyAction])
}

func showDeleteWarning(for indexPath: IndexPath) {
    //Create the alert controller and actions
    let alert = UIAlertController(title: "Warning Title", message: "Warning Message", preferredStyle: .alert)

    let cancelAction = UIAlertAction(title: "Cancel", style: .cancel, handler: nil)

    let deleteAction = UIAlertAction(title: "Delete", style: .destructive) { _ in
        DispatchQueue.main.async {
            self.namesArray.remove(at: indexPath.row)
            self.imagesArray.remove(at: indexPath.row)
            self.tableView.deleteRows(at: [indexPath], with: .fade)
        }
    }

    //Add the actions to the alert controller
    alert.addAction(cancelAction)
    alert.addAction(deleteAction)

    //Present the alert controller
    present(alert, animated: true, completion: nil)
}

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