[ios] 'Invalid update: invalid number of rows in section 0

I've read all of the related posts regarding this and I am still having an error:

'Invalid update: invalid number of rows in section 0.  The number of rows contained in an existing section after the update (5) must be equal to the number of rows contained in that section before the update (5), 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 are the details:

in .h I have an NSMutableArray:

@property (strong,nonatomic) NSMutableArray *currentCart;

In .m my numberOfRowsInSection looks like this:

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    // Return the number of rows in the section.


    return ([currentCart count]);

}

To enable delete and remove the object from the array:

// Editing of rows is enabled
- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath {
    if (editingStyle == UITableViewCellEditingStyleDelete) {

        //when delete is tapped
        [tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade];

        [currentCart removeObjectAtIndex:indexPath.row];


    }
}

I thought that by having my number of sections relying on the count of the array I'm editing it would ensure the proper number of rows? Can't this be done without having to reload the table when you delete a row anyway?

This question is related to ios objective-c arrays nsmutablearray

The answer is


In my case issue was that numberOfRowsInSection was returning similar number of rows after calling tableView.deleteRows(...).

Since this was the required behaviour in my case, I ended up calling tableView.reloadData() instead of tableView.deleteRows(...) in cases where numberOfRowsInSection will remain same after deleting a row.


Here is some code from above added with actual action code (point 1 and 2);

func tableView(_ tableView: UITableView, trailingSwipeActionsConfigurationForRowAt indexPath: IndexPath) -> UISwipeActionsConfiguration? {
    let deleteAction = UIContextualAction(style: .destructive, title: "Delete") { _, _, completionHandler in

        // 1. remove object from your array
        scannedItems.remove(at: indexPath.row)
        // 2. reload the table, otherwise you get an index out of bounds crash
        self.tableView.reloadData()

        completionHandler(true)
    }
    deleteAction.backgroundColor = .systemOrange
    let configuration = UISwipeActionsConfiguration(actions: [deleteAction])
    configuration.performsFirstActionWithFullSwipe = true
    return configuration
}

Swift Version --> Remove the object from your data array before you call

func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCellEditingStyle, forRowAt indexPath: IndexPath) {
    if editingStyle == .delete {
        print("Deleted")

        currentCart.remove(at: indexPath.row) //Remove element from your array 
        self.tableView.deleteRows(at: [indexPath], with: .automatic)
    }
}

Examples related to ios

Adding a UISegmentedControl to UITableView Crop image to specified size and picture location Undefined Symbols error when integrating Apptentive iOS SDK via Cocoapods Keep placeholder text in UITextField on input in IOS Accessing AppDelegate from framework? Autoresize View When SubViews are Added Warp \ bend effect on a UIView? Speech input for visually impaired users without the need to tap the screen make UITableViewCell selectable only while editing Xcode 12, building for iOS Simulator, but linking in object file built for iOS, for architecture arm64

Examples related to objective-c

Adding a UISegmentedControl to UITableView Keep placeholder text in UITextField on input in IOS Accessing AppDelegate from framework? Warp \ bend effect on a UIView? Use NSInteger as array index Detect if the device is iPhone X Linker Command failed with exit code 1 (use -v to see invocation), Xcode 8, Swift 3 ITSAppUsesNonExemptEncryption export compliance while internal testing? How to enable back/left swipe gesture in UINavigationController after setting leftBarButtonItem? Change status bar text color to light in iOS 9 with Objective-C

Examples related to arrays

PHP array value passes to next row Use NSInteger as array index How do I show a message in the foreach loop? Objects are not valid as a React child. If you meant to render a collection of children, use an array instead Iterating over arrays in Python 3 Best way to "push" into C# array Sort Array of object by object field in Angular 6 Checking for duplicate strings in JavaScript array what does numpy ndarray shape do? How to round a numpy array?

Examples related to nsmutablearray

'Invalid update: invalid number of rows in section 0 How do I convert NSMutableArray to NSArray? The best way to remove duplicate values from NSMutableArray in Objective-C? How do I sort an NSMutableArray with custom objects in it?