Delete row at index path error - ios

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 (1) must be equal to the number of rows contained in that section before the update (1), 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).'
Here's the code:
func tableView(tableView: UITableView, commitEditingStyle editingStyle: UITableViewCellEditingStyle, forRowAtIndexPath indexPath: NSIndexPath) {
if editingStyle == UITableViewCellEditingStyle.Delete {
let delegate = UIApplication.sharedApplication().delegate as! AppDelegate
let managedContext = delegate.managedObjectContext!
var error: NSError?
let fetchRequest = NSFetchRequest(entityName: "Task")
let fetchedResults = managedContext.executeFetchRequest(fetchRequest, error: &error) as! [NSManagedObject]
managedContext.deleteObject(fetchedResults[indexPath.row])
if managedContext.save(&error) == true {
println("Yes, you did it!")
}
//All the above code works fine.
table.deleteRowsAtIndexPaths([indexPath], withRowAnimation: UITableViewRowAnimation.Fade)
}
}
UPDATE:
func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return tasks.count
}

You have to update the tasks variable before deleteRowsAtIndexPaths be called:
managedContext.deleteObject(fetchedResults[indexPath.row])
tasks.removeAtIndex(indexPath.row)
table.deleteRowsAtIndexPaths([indexPath], withRowAnimation: UITableViewRowAnimation.Fade)

Problem is you delete data from core data but that data is still in your source array.
you have to delete that data from your source array before delete row

Related

CoreData app crashes when deleting row from TableView

I have a dozen table view controllers that all work as expected, then I have this one which crashes with:
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 (1) must be equal to the number of rows contained in that section before the update (1), 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).'
The code doing this has been modified several times with different options but to no effect.
import UIKit
import CoreData
class QTypeVCY: UITableViewController, NSFetchedResultsControllerDelegate
{
let app = UIApplication.shared.delegate as! AppDelegate
override func viewDidLoad()
{
super.viewDidLoad()
}
override func numberOfSections(in tableView: UITableView) -> Int
{
let sections = frc.sections
return sections!.count
}
override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int
{
guard let sections = self.frc.sections else
{
fatalError("No sections in fetchedResultsController")
}
let sectionInfo = sections[section]
return sectionInfo.numberOfObjects
}
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell
{
let cell = tableView.dequeueReusableCell(withIdentifier: "QQQQ", for: indexPath)
let qtype = frc.object(at: indexPath)
cell.textLabel?.text = qtype.title
return cell
}
override func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCellEditingStyle, forRowAt indexPath: IndexPath) {
if editingStyle == .delete
{
do
{
let qtype = frc.object(at: indexPath)
let context = self.frc.managedObjectContext
context.delete(qtype)
try context.save()
tableView.deleteRows(at: [indexPath], with: .fade)
}
catch
{
debugPrint(error)
}
} 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
}
}
lazy var frc: NSFetchedResultsController<Qtype> =
{
let context = self.app.persistentContainer.viewContext
let req: NSFetchRequest<Qtype> = Qtype.fetchRequest()
req.fetchBatchSize = 10
let sortDescriptor1 = NSSortDescriptor(key: #keyPath(Qtype.specialty), ascending:true)
let sortDescriptor2 = NSSortDescriptor(key: #keyPath(Qtype.title), ascending:true)
req.sortDescriptors = [sortDescriptor1, sortDescriptor2]
let afrc = NSFetchedResultsController(fetchRequest: req, managedObjectContext: context, sectionNameKeyPath: nil, cacheName: nil)
afrc.delegate = self
do
{
try afrc.performFetch()
}
catch
{
print(error.localizedDescription)
fatalError("Abort while fetching Qtype")
}
return afrc
}()
}
The crash occurs on the tableview.deleteRows statement. I have tried surrounding the code with beginUpdate/endUpdates, with and without the performFetch, even tried re-entering the code in case I had a typo that I missed. This same basic code is working fine on other tables/view controllers, just this one.
The entity is just made up of strings. I had it with and without relationships to other entities.
The row is deleted since the next time I run the app it is missing. Also, one other thing about this table is that calling reloadData after adding a new object does not add the row. I need to leave the tableview and reenter it. I'm sure the two are related but can't say why.
Since originally posting this, I included the entire VC code instead of just the offending code. I have also tried swapping the Entity with a different entity where this issue does not occur, but the program still crashes even with a different entity.
You forgot to remove the item also from the data source array
let qtype = qtypes[indexPath.row]
let context = self.frc.managedObjectContext
context.delete(qtype)
try context.save()
qtypes.remove(at: indexPath.row) // <--
tableView.deleteRows(at: [indexPath], with: .fade)
I wish I could offer the actual solution, but the above code now works. I had updated XCode to the 1/24/18 version but I don't think that is the solution. I also stripped out a few things I had in the original code that crashed, but then I put them back and it still works. I suspect I had a typo somewhere, but after spending a half hour trying to locate it, I'm declaring victory and moving on.
I just solloved a problem similar to yours.
when deleted data in CoreData, TableView data array also delete before appDelegate.saveContext()
Code in func tableView(_ tableView: UITableView, trailingSwipeActionsConfigurationForRowAt indexPath: IndexPath)
self.tableviewArrayData.remove(at: indexPath.row)
tableView.deleteRows(at: [indexPath], with: .fade)
appDelegate.saveContext()

Swift TableView deleteRowsAtIndexPaths NSException

I have a dynamic TableView and want to delete rows with an animation.
My Code:
struct TableItem {
let text: String
let id: String
let creationDate: String
let bug: String
let comments: String
}
var sections = Dictionary<String, Array<TableItem>>()
var sortedSections = [String]()
//Some other Code
override func tableView(tableView: UITableView, commitEditingStyle editingStyle: UITableViewCellEditingStyle, forRowAtIndexPath indexPath: NSIndexPath) {
}
override func tableView(tableView: UITableView, editActionsForRowAtIndexPath indexPath: NSIndexPath) -> [UITableViewRowAction]? {
let setChecked = UITableViewRowAction(style: UITableViewRowActionStyle.Default, title: "Erledigt" , handler: { (action:UITableViewRowAction!, indexPath:NSIndexPath!) -> Void in
var tableSection = self.sections[self.sortedSections[indexPath.section]]
let tableItem = tableSection![indexPath.row]
//Not important HTTP POST Code
if(success == 1)
{
NSLog("SUCCESS");
self.tableView.beginUpdates()
tableSection?.removeAtIndex(indexPath.row)
self.tableView.deleteRowsAtIndexPaths([indexPath], withRowAnimation: .Left)
self.tableView.endUpdates()
//self.getChecked()
}
}
return [setChecked]
}
If I run this Code I get the following error-message:
Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'Invalid update: invalid number of rows in section 6. 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).'
I have no idea what I'm doing wrong.
Thanks for your help.
That's the value type trap.
Swift collection types are structs which have value semantics unlike classes which have reference semantics.
The line var tableSection = self.sections[self.sortedSections[indexPath.section]] makes a copy of the object and leaves self.sections unchanged.
After removing the item from the list you have to assign the array back to self.sections.
tableSection?.removeAtIndex(indexPath.row)
self.sections[self.sortedSections[indexPath.section]] = tableSection

Deleting Rows in UITableView Swift 3

okay im making an app where you add items to a cart and it updates as you add. i do all the adding fine, but i cant get deleting to work. in the cart cell i would need to remove from 3 arrays, but that doesn't seem to be the problem because i keep getting this error:
"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 (1) must be equal to the number of rows contained in that section before the update (1), 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).'"
i'm not really sure what i'm doing wrong here. i've followed a few tutorials and they all seem to be doing the same thing. any help is appreciated thanks in advance.
heres some of my code:
//declaring arrays to show in cell
var cartKeys = [String]()
var cartValues = [String]()
var deets = [[String]]()
var count = 0
//populating arrays from original arrays
func populateCart(){
for (key,value) in MenuStore.shared.cart {
self.cartKeys.append(key)
self.cartValues.append(value)
}
for i in MenuStore.shared.cartAndItems{
for (k,v) in i {
deets.append(v)
}
}
print("DEETS \(deets)")
for c in cartView.visibleCells {
count += 1
}
}
func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCellEditingStyle, forRowAt indexPath: IndexPath) {
switch tableView{
case cartView:
if editingStyle == .delete{
let index = indexPath.row
print(index)
cartKeys.remove(at: index)
cartValues.remove(at: index)
deets.remove(at: index)
tableView.deleteRows(at: [indexPath], with: .automatic)
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
switch tableView{
case cartView:
let cartCell = tableView.dequeueReusableCell(withIdentifier: "cartCell", for: indexPath) as? CartCell
cartCell?.cartTitle.text = cartKeys[(indexPath as NSIndexPath).row]
cartCell?.cartPrice.text = cartValues[(indexPath as NSIndexPath).row]
cartCell?.cartDetails.text = deets[count].joined(separator: ", ")
return cartCell!
ps. if anyone wants to help with replacing the visible cells call thatd be great. id like to loop through all the cells even if their not visible on the screen.

Trying to delete an entity from core data, i get...?

I am trying to delete an entity from core data but i am getting the following error:
The number of rows contained in an existing section after the update (10) must be equal to the number of rows contained in that section before the update (10),
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).'
Here is my tableview function
// MARK: delete
func tableView(tableView: UITableView, commitEditingStyle editingStyle: UITableViewCellEditingStyle, forRowAtIndexPath indexPath: NSIndexPath) {
let deletedRow:UITableViewCell = tableView.cellForRowAtIndexPath(indexPath)!
if editingStyle == UITableViewCellEditingStyle.Delete {
// remove the deleted item from the model
moContext.deleteObject(scannedVisitors[indexPath.row] as NSManagedObject)
scannedVisitors.removeAtIndex(indexPath.row)
do {
try moContext.save()
print("deleted and saved")
} catch {
// Replace this implementation with code to handle the error appropriately.
// abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
let nserror = error as NSError
NSLog("Unresolved error \(nserror), \(nserror.userInfo)")
abort()
}
// remove the deleted item from the `UITableView`
tableView.deleteRowsAtIndexPaths([indexPath], withRowAnimation: UITableViewRowAnimation.Automatic)
deletedRow.accessoryType = UITableViewCellAccessoryType.None
print("Deleted + accessory")
}
}
I have the fetchRequest in viewDidAppear and not in viewDidLoad
override func viewDidAppear(animated: Bool) {
do {
let request = NSFetchRequest(entityName: "ScannedVisitor")
scannedVisitors = try moContext.executeFetchRequest(request) as! [ScannedVisitor]
self.tableView.reloadData()
} catch let error as NSError {
print(error)
}
}
When i restart the app the entity has been deleted, but during the deletion action i get the runtime error.
How can i fix this?
[EDIT] taking a closer look i am seeing this part being "parsed" 3 times
func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
print("Rows \(scannedVisitors.count)")
return scannedVisitors.count
}
because it prints
Rows 0
Rows 0
Rows 6
Don't get the object to be deleted from the view, get it from the model and do all deletion tasks regarding the UI before saving the context.
let objectToDelete = scannedVisitors[indexPath.row]
scannedVisitors.removeAtIndex(indexPath.row)
tableView.deleteRowsAtIndexPaths([indexPath], withRowAnimation:.Automatic)
moContext.deleteObject(objectToDelete)
do {
try moContext.save()
...
Actually it's not needed to change the accessory type of a cell which is going to be removed anyway

commitEditingStyle makes my app crash

My app has crashed multiple times while implementing a swipe to delete feature.
reason: 'Invalid update: invalid number of rows in section 0.
The number of rows contained in an existing section after the update
(1) must be equal to the number of rows contained in that section
before the update (1), 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).'
I read somewhere that this has to do with rows not being decremented by 1 at numberOfRowsInSection so I created a var deleted :Bool? to change whenever a data / row is deleted. Now, I just swipe and delete once and my app crashes after another attempt.
Here are the codes related to this:
var myFavs : [MyFavourites]?
var deleted :Bool?
override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
// #warning Incomplete implementation, return the number of rows
if deleted == true {
return myFavs!.count - 1
} else {
return (myFavs?.count)!
}
}
// Override to support editing the table view.
override func tableView(tableView: UITableView, commitEditingStyle editingStyle: UITableViewCellEditingStyle, forRowAtIndexPath indexPath: NSIndexPath) {
if editingStyle == .Delete {
tableView.beginUpdates()
//Delete from CD.
let appDel: AppDelegate = UIApplication.sharedApplication().delegate as! AppDelegate
let context: NSManagedObjectContext = appDel.managedObjectContext
let myFavo = myFavs![indexPath.row]
context.deleteObject(myFavo as MyFavourites)
do {
try context.save()
} catch _ {
}
// Delete the row from the data source
tableView.deleteRowsAtIndexPaths([indexPath], withRowAnimation: .Fade)
deleted = true
tableView.endUpdates()
tableView.reloadData()
}
}
[Edit]
My Data source var myFavs : [MyFavourites]? is a generated NSManagedObject subclass from CoreData. I forgot to mention that it deletes successfully from coreData when I restart the App from Simulator.
Here's my Data Source code if necessary.
extension MyFavourites {
#NSManaged var id: String?
}
What am I doing wrong ?

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