Удалить UITableView строки ж/CoreData и NSFetchedResultsController

Question

После попытки удалить строку из Tableview приложения является оканчивающиеся следующей ошибкой:

Terminating app due to uncaught exception 
'NSInternalInconsistencyException', reason: 'Invalid update: invalid 
number of rows in section 0. The number of rows contained in an 
existing section after the update (2) must be equal to the number of 
rows contained in that section before the update (2), plus or minus 
the number of rows inserted or deleted from that section (0 inserted, 
1 deleted) and plus or minus the number of rows moved into or out of 
that section (0 moved in, 0 moved out).' 

Вот код:

import UIKit 
import CoreData 

class PlayerTableViewController: UITableViewController { 


lazy var fetchedResultsController:NSFetchedResultsController<TCSpieler> = { 
    let fetch:NSFetchRequest<NSFetchRequestResult> = NSFetchRequest(entityName: "TCSpieler") 
    let sortByName = NSSortDescriptor(key: "name", ascending: true) 
    fetch.sortDescriptors = [sortByName] 
    let managedObjectContext = (UIApplication.shared.delegate as! AppDelegate).persistentContainer.viewContext 
    let frc = NSFetchedResultsController(fetchRequest: fetch, managedObjectContext: managedObjectContext, sectionNameKeyPath: nil, cacheName: nil) 
    try! frc.performFetch() 
    return frc as! NSFetchedResultsController<TCSpieler> 
}() 

// MARK: - Table view data source 

override func numberOfSections(in tableView: UITableView) -> Int { 
    return fetchedResultsController.sections?.count ?? 1 
} 

override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int { 
    return fetchedResultsController.sections![section].numberOfObjects 
} 

override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell { 

    let cell = tableView.dequeueReusableCell(withIdentifier: "PlayerCell", for: indexPath) as! PlayerTableViewCell 
    // Configure the cell... 
    cell.player = fetchedResultsController.object(at: indexPath) 

    return cell 
} 


// Override to support conditional editing of the table view. 
override func tableView(_ tableView: UITableView, canEditRowAt indexPath: IndexPath) -> Bool { 
    // Return false if you do not want the specified item to be editable. 
    return true 
} 

// Override to support editing the table view. 
override func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCellEditingStyle, forRowAt indexPath: IndexPath) { 
    if editingStyle == .delete { 
    let rowToDelete = fetchedResultsController.object(at: indexPath) 
    fetchedResultsController.managedObjectContext.delete(rowToDelete) 
     try! fetchedResultsController.managedObjectContext.save() 

     // Delete the row from the data source 
     tableView.deleteRows(at: [indexPath], with: .fade) 
    } else if editingStyle == .insert { 
     // Create a new instance of the appropriate class, insert it into the array, and add a new row to the table view 
    } 

} 

Answer 1

Это работает для меня:

override func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCellEditingStyle, forRowAt indexPath: IndexPath) { 

     if editingStyle == UITableViewCellEditingStyle.delete { 
      let managedObjectContext: NSManagedObjectContext = (UIApplication.shared.delegate as! AppDelegate).managedObjectContext; 
      let managedObject: NSManagedObject = fetchedResultsController.object(at: indexPath) as! NSManagedObject; 
      managedObjectContext.delete(managedObject); 
      do { 
       try managedObjectContext.save(); 
       tableView.deleteRows(at: [indexPath], with: UITableViewRowAnimation.fade); 
      } catch { 
       // Error occured while deleting objects 
      } 



     } else if editingStyle == UITableViewCellEditingStyle.insert { 

     } 

    }