Question

我们成功实现了从Core Data中保存和读取，但是当删除随机单元格时，我们在从Core Data中删除数据时遇到问题。如何从tableView中删除随机单元格时从Core Data中删除数据???我们输入了一些代码，比如从数组中删除最后一个索引，但它不起作用......

2cd Vc

    import UIKit
import CoreData

class TableViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {

@IBOutlet weak var tableView: UITableView!

var item = [NSManagedObject] ()

override func viewDidLoad() {
    super.viewDidLoad()

    self.tableView.delegate = self
    self.tableView.dataSource = self
}

func tableView(tableView:UITableView, numberOfRowsInSection section:Int) -> Int
{
    return item.count
}

func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell
{

    let cell = tableView.dequeueReusableCellWithIdentifier("Cell", forIndexPath: indexPath)
    let person = item[indexPath.row]
    cell.textLabel!.text = person.valueForKey("username") as? String
    cell.detailTextLabel?.text = person.valueForKey("passwords") as? String

    return cell
}

 func tableView(tableView: UITableView, commitEditingStyle editingStyle: UITableViewCellEditingStyle, forRowAtIndexPath indexPath: NSIndexPath) {


// WHAT TO TYPE HERE TO REMOVE DATA FROM CORE DATA WHEN RANDOM CELL IS DELETED
    let context: NSManagedObjectContext = (UIApplication.sharedApplication().delegate as! AppDelegate).managedObjectContext

    do {
        try context.save()
    } catch _ {
    }
}

override func viewWillAppear(animated: Bool) {
    super.viewWillAppear(animated)

    let appDelegate = UIApplication.sharedApplication().delegate as! AppDelegate
    let managedContext = appDelegate.managedObjectContext
    let fetchRequest = NSFetchRequest(entityName: "Users")

    do {
        let results =
        try managedContext.executeFetchRequest(fetchRequest)
        item = results as! [NSManagedObject]
    } catch let error as NSError {
        print("Could not fetch \(error), \(error.userInfo)")
    }
}

Answer 1

我发现它像这样工作

func tableView(tableView: UITableView, commitEditingStyle editingStyle: UITableViewCellEditingStyle, forRowAtIndexPath indexPath: NSIndexPath) {

  switch editingStyle {
    case .Delete:
        // remove the deleted item from the model
        let appDel:AppDelegate = UIApplication.sharedApplication().delegate as! AppDelegate
        let context:NSManagedObjectContext = appDel.managedObjectContext
        context.deleteObject(item[indexPath.row] as NSManagedObject)
        item.removeAtIndex(indexPath.row)
        do{
            try context.save()
        }catch{
            print("Error, data not saved!")
        }

        //tableView.reloadData()
        // remove the deleted item from the `UITableView`
        self.tableView.deleteRowsAtIndexPaths([indexPath], withRowAnimation: .Fade)
    default:
        return

    }

Swift 2.0 Core Data TableView删除单元格

1 个答案: