ios - 删除单元格之前提醒 Controller Swift Xcode

Question

我想知道如何在删除单元格之前显示删除确认(警报)。这些单元格是带有信息的字符，因此如果用户错误地删除(滑动)单元格，那将是很糟糕的。

这是允许我删除行的代码片段。我使用 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

您可以将显示 UIAlertController 的代码拉出到一个单独的方法中，您可以在用户按删除键时调用该方法。下面是代码，确保闭包中包含的所有表示逻辑都被分派(dispatch)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)
}