UITableViewRowAction和UIAlertController

Question

我已经用UITableView :编辑和删除创建了UITableViewRowAction。当按下删除时，确认应该显示为UIAlertController。如果用户按下删除，则应删除单元格，如果用户按下“取消”，则应删除单元格，而UIAlertController应消失。我编写了这段代码，但它不像预期的那样工作。

let edit = UITableViewRowAction(style: .normal, title: "Изменить") { action, index in
        self.performSegue(withIdentifier: "LEDChangesSegue", sender: self.tableView.cellForRow(at: indexPath))
    }
    edit.backgroundColor = UIColor.init(red: 0, green: 122.0/256.0, blue: 1, alpha: 1)

    let delete = UITableViewRowAction(style: .normal, title: "Удалить") { action, index in

        let alertController = UIAlertController(title: self.ledControllers[indexPath.row].name, message: "Действительно удалить этот контроллер?", preferredStyle: .alert)
        var answer = true

        let cancelAction = UIAlertAction(title: "Отмена", style: .cancel) { (action:UIAlertAction!) in answer = false
        }

        let deleteAction = UIAlertAction(title: "Удалить", style: .destructive ) { (action:UIAlertAction!) in answer = true
        }
        alertController.addAction(deleteAction)
        alertController.addAction(cancelAction)
        self.present(alertController, animated: true, completion: nil)

        if  answer {
            self.ledControllers.remove(at: index.row)
            saveLED(self.ledControllers)
            self.tableView.deleteRows(at: [index], with: .fade)
        }}
    delete.backgroundColor = UIColor.red()

    return [edit, delete]

始终返回原始值var answer = true，而不是我在UIAlertController中单击的内容。是什么修复了代码才能使它正确工作？

Answer 1

解决方案1

您可以直接这样做，而不必接受变量answer，因为这是局部变量，并且在此块之外没有作用域。

let edit = UITableViewRowAction(style: .normal, title: "Изменить") { action, index in
    self.performSegue(withIdentifier: "LEDChangesSegue", sender: self.tableView.cellForRow(at: indexPath))
}
edit.backgroundColor = UIColor.init(red: 0, green: 122.0/256.0, blue: 1, alpha: 1)

let delete = UITableViewRowAction(style: .normal, title: "Удалить") { action, index in

    let alertController = UIAlertController(title: self.ledControllers[indexPath.row].name, message: "Действительно удалить этот контроллер?", preferredStyle: .alert)

    let cancelAction = UIAlertAction(title: "Отмена", style: .cancel) { (action:UIAlertAction!) in
    }

    let deleteAction = UIAlertAction(title: "Удалить", style: .destructive ) { (action:UIAlertAction!) in 
        self.ledControllers.remove(at: index.row)
        self.saveLED(self.ledControllers)
        self.tableView.deleteRows(at: [index], with: .fade)
    }
    alertController.addAction(deleteAction)
    alertController.addAction(cancelAction)
    self.present(alertController, animated: true, completion: nil)

delete.backgroundColor = UIColor.red()

return [edit, delete]

解决方案2

如果您真的想用变量answer(实际上没有意义使用)来实现这一点，那么编写一个单独的函数来删除该行。

func deleteRowNow(answer : Bool, forRow : NSIndexPath)
{
    if  answer {
        self.ledControllers.remove(at: index.row)
        saveLED(self.ledControllers)
        self.tableView.deleteRows(at: [index], with: .fade)
    }}
}

并在UIAlertAction块内调用它

let edit = UITableViewRowAction(style: .normal, title: "Изменить") { action, index in
    self.performSegue(withIdentifier: "LEDChangesSegue", sender: self.tableView.cellForRow(at: indexPath))
}
edit.backgroundColor = UIColor.init(red: 0, green: 122.0/256.0, blue: 1, alpha: 1)

let delete = UITableViewRowAction(style: .normal, title: "Удалить") { action, index in

    let alertController = UIAlertController(title: self.ledControllers[indexPath.row].name, message: "Действительно удалить этот контроллер?", preferredStyle: .alert)
    var answer = true

    let cancelAction = UIAlertAction(title: "Отмена", style: .cancel) { (action:UIAlertAction!) in 
          answer = false
          self.deleteRowNow(answer, forRow : index)
    }

    let deleteAction = UIAlertAction(title: "Удалить", style: .destructive ) { (action:UIAlertAction!) in 
          answer = true
          self.deleteRowNow(answer, forRow : index)
    }
    alertController.addAction(deleteAction)
    alertController.addAction(cancelAction)
    self.present(alertController, animated: true, completion: nil)

delete.backgroundColor = UIColor.red()

return [edit, delete]