Question

我有这个功能 func deleteDayTracker(at indexPath: IndexPath)，我想在alertAction中调用它，因此当按下警报操作按钮时，将调用deleteDayTracker函数并在其中执行代码。我尝试了ViewController.deleteDayTracker(self)，但随后出现错误Expression解析为未使用的函数。如何在alertAction中调用deleteDayTracker。这是您的完整代码

func deleteDayTracker(at indexPath: IndexPath)
{
    let appDelegate = UIApplication.shared.delegate as! AppDelegate
    let context = appDelegate.persistentContainer.viewContext
    context.delete(numberOfDays[indexPath.row])
    context.delete(eventName[indexPath.row])
    context.delete(eventDate[indexPath.row])


    do
    {
        try context.save()
    }
    catch
    {
        let alert = UIAlertController(title: nil, message: "Unable to delete event", preferredStyle: .alert)
        let okButton = UIAlertAction(title: "OK", style: .default, handler: nil)
        alert.addAction(okButton)
        self.present(alert, animated: true, completion: nil)
    }
    tableView.reloadData()
}


@IBAction func editButton(_ sender: Any)
{

    let editAlert = UIAlertController(title: nil, message: "Delete this day tracker?", preferredStyle: .actionSheet)
    let deleteButton = UIAlertAction(title: "Delete", style: .destructive, handler: self.deleteCell)
    let cancelButton = UIAlertAction(title: "Cancel", style: .cancel, handler: nil)
    editAlert.addAction(deleteButton)
    editAlert.addAction(cancelButton)
    if let alert = editAlert.popoverPresentationController
    {
        alert.sourceView = self.view
        alert.sourceRect = CGRect(x: self.view.bounds.midX, y: self.view.bounds.midY, width: 0, height: 0)
        alert.permittedArrowDirections = []
    }

    self.present(editAlert, animated: true, completion: nil)
}

func deleteCell(alert: UIAlertAction!)
{
    ViewController.deleteDayTracker(self)
}

Answer 1

您使用参数“ at indexPath”创建了类型为“ IndexPath”的方法例如，您应该使用根据参数调用方法。

func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {

     UIAlertAction(title: "OK", style: UIAlertActionStyle.Default) { _ in
         self.deleteDayTracker(at: indexPath)
   }
}

表达式解析为具有特殊功能的未使用功能

1 个答案: