CODEWITHSUNDEEP
iphoneiosuitableviewcore-data
yong ho
yong ho

Reputation: 4042

Delete a table view cell but " invalid number of rows" shows

My tableview datasoure comes from a array, and it gets data from managed object context's executeFetchRequest method. In the commitEditingStyle delegate, I got 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),

the delegate:

- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath
{
    if (editingStyle == UITableViewCellEditingStyleDelete) {
        [self.managedOjbectContext deleteObject:[self.myEvents objectAtIndex:indexPath.row]];
        [self.tableView deleteRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationFade];
        [self.tableView reloadData];
    }
}

Upvotes: 1

Views: 784

Answers (5)

bturner
bturner

Reputation: 514

If you delete a cell from you TableView, your datasource needs to be updated to recognize these changes.

There is a method called numberOfRowsInSection: This method returns the number of cells the table view should be displaying. More than likely its using an array or some other type of data structure. You need to make sure that this array is kept in sync with any changes made to the table view itself. If you tell the table view to remove a view, you need to also update the backing data of the table view to reflect the changes.

Upvotes: 0

blaa
blaa

Reputation: 438

Why not encapsulate the deleting and all between [self.tableView beginUpdates] and [self.tableView endUpdates]?

- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath
{
    if (editingStyle == UITableViewCellEditingStyleDelete) {
        [self.tableView beginUpdates];
        [self.managedOjbectContext deleteObject:[self.myEvents objectAtIndex:indexPath.row]];
        [self.tableView deleteRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationFade];
        [self.tableView endUpdates];
    }

}

As per: Apple's Table View Programmming Guidelines

Upvotes: 0

Ravindra Bagale
Ravindra Bagale

Reputation: 17655

try to use [tableView beginUpdates];and [tableView endUpdates]; dont use reloadData like this

[tableView beginUpdates];
if (editingStyle == UITableViewCellEditingStyleDelete) {
        [self.managedOjbectContext deleteObject:[self.myEvents objectAtIndex:indexPath.row]];
        [self.tableView deleteRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationFade];

    }
[tableView endUpdates];

Upvotes: 0

gcamp
gcamp

Reputation: 14662

The error says it all, you removed an a row, but your delegate stills says it's there.

My guess is that you didn't remove your object from self.myEvents. Removing the object from the managed context doesn't remove it from your array.

Assuming self.myEvents is an NSMutableArray*

[self.myEvents removeObjectAtIndex:indexPath.row]

Upvotes: 1

apascual
apascual

Reputation: 2980

You should delete the entry from your NSArray and then reload the tableView, that way won't have inconsistencies...

Upvotes: 1

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