UITableView 内容在删除后不会被删除？ [斯威夫特 3.0 - Xcode 8]

Question

我试图删除 UITableView 中的单元格，但是当我删除它们时，它们会在我重新加载应用程序后重新出现。我从与核心数据一起存储值的同一个数组中删除。我是否也必须直接从 coreData 中删除？我怎么做？

这是我的代码：

///Function to remove TableView Cells

public func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCellEditingStyle, forRowAt indexPath: IndexPath) {
if editingStyle == UITableViewCellEditingStyle.delete
{
    SetTIME.remove(at: indexPath.row)
    if SaveData.count == 4 {
        SaveData.remove(at: myIndex*4)
        SaveData.remove(at: (myIndex*4)+1)
        SaveData.remove(at: (myIndex*4)+2)
        SaveData.remove(at: (myIndex*4)+3)}
        tableView.reloadData()
    }

}



 ///CoreData

override func viewDidLoad() {
    super.viewDidLoad()

    let appDelegate = UIApplication.shared.delegate as! AppDelegate
    let context = appDelegate.persistentContainer.viewContext
    let newTrip = NSEntityDescription.insertNewObject(forEntityName: "Sets", into: context)
    if DataGrab.count == 4{ // need to change after storing data in VC2 before sending
    newTrip.setValue(DataGrab[0], forKey: "set1")
    newTrip.setValue(DataGrab[1], forKey: "set4")
    newTrip.setValue(DataGrab[2], forKey: "set3")
    newTrip.setValue(DataGrab[3], forKey: "set2")}


    do {
        try context.save()
        print("Saved")
    }
    catch{
        //ProcessError
    }


    let request = NSFetchRequest<NSFetchRequestResult>(entityName: "Sets")
    request.returnsObjectsAsFaults = false

    do {
        let results = try context.fetch(request)
        if results.count > 0 {
            for result in results {
                if let set1 = (result as AnyObject).value(forKey: "set1") as? String
                {
                    if SaveData.contains(set1){

                    } else {
                    SaveData.append(set1)
                        SetTIME.append(set1)

                if let set2 = (result as AnyObject).value(forKey: "set2") as? String
                {
                    SaveData.append(set2)
                }
                if let set3 = (result as AnyObject).value(forKey: "set3") as? String
                {
                    SaveData.append(set3)
                }
                if let set4 = (result as AnyObject).value(forKey: "set4") as? String
                {
                    SaveData.append(set4)
                        }
                    }
                }
            }
        }
    }
    catch{
        //ProcessErrors
    }

Answer 1

您可以将 NSFetchedResultsController 与 UITableview 一起使用。这将负责核心数据中对象的删除/添加/编辑。

以下是创建 NSFetchedResultsController 的链接

https://cocoacasts.com/populate-a-table-view-with-nsfetchedresultscontroller-and-swift-3/

https://developer.apple.com/library/content/documentation/Cocoa/Conceptual/CoreData/nsfetchedresultscontroller.html

Answer 2

    @IBOutlet weak var btnremove: UIButton!
        @IBOutlet weak var managetable: UITableView!
        var arrayStudent:[StudentData] = []
        var streno:String!
        let appDelegate = UIApplication.shared.delegate as! AppDelegate
        var managedContext:NSManagedObjectContext!
        var entity:NSEntityDescription!

    func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath)
        {
            let obj = arrayStudent[indexPath.row]
            streno = obj.strEnrollment
            print(streno) 
           deleteFeed(eno:streno )
        }
func deleteFeed(eno:String)
    {
        managedContext = appDelegate.persistentContainer.viewContext
        let fetchRequest = NSFetchRequest<NSFetchRequestResult>(entityName:"Student")
        fetchRequest.predicate = NSPredicate(format: "eno = %@", "\(eno)")
        do
        {
            let fetchedResults =  try managedContext!.fetch(fetchRequest) as? [NSManagedObject]

            for entity in fetchedResults! {

                managedContext?.delete(entity)
                do
                {
                    try managedContext.save()
                    _ = self.navigationController?.popViewController(animated: true)

                }
                catch let error as Error!
                {
                    print(error.localizedDescription)
                }
                managetable.reloadData()

            }
        }
        catch _ {
            print("Could not delete")

        }
    }