CODEWITHSUNDEEP
iosobjective-cuitableview
kevin nguyen
kevin nguyen

Reputation: 29

Terminating with uncaught exception of type NSException when deleting row from UITableView

I'm working on an app that will update and add user's coordinate to a UITableView when the user has traveled over a preset distance interval. The coordinates will be automatically added to an NSMutableArray, and I use the array to update the table.

Everything load up and work fine (I can edit the table by moving and re-ordering the rows) but whenever I chose to delete a specific row, the program crash with the error "libc++abi.dylib: terminating with uncaught exception of type NSException".

- (void) tableView:( UITableView *) tableView commitEditingStyle:( UITableViewCellEditingStyle) editingStyle forRowAtIndexPath:( NSIndexPath *) indexPath {
    if (editingStyle == UITableViewCellEditingStyleDelete) {

        NSArray *items = [[G5SharedStore sharedStore]allCoords];
        G5SharedStore *item = items[indexPath.row];
        [[G5SharedStore sharedStore]removeItem:item];
        //THIS IS WHERE THE ERROR OCCURS
        [tableView deleteRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationFade];
    }
}

The last line is what causes the error, but I'm new to objective-c, so I'm not sure how to fix this. Any help would be appreciated. Let me know if you need more details.

Thanks in advance.

**Edit: Ok, I played around with the code this morning and it works. The problem is that the array keeps adding more and more items, but the tableview doesn't, unless I go back out and click "show table" button again to refresh it. So whenever I delete something in the tableview, the table's size is inconsistent with the array's size therefore I get the error. Here's my new problem, I tried to solve the above problem by making the table automatically update its data using:

[tableView reloadData];

The table does update, but it keeps adding blank cells ... with no data in it. Here's where I added the above:

- (UITableViewCell *) tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
        UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:@" UITableViewCell"
                                                        forIndexPath:indexPath];

        NSArray *items = [[G5SharedStore sharedStore] allCoords];
        G5SharedStore *item = items[indexPath.row];
        cell.textLabel.text = [item description];
        [tableView reloadData];
        return cell;
}

Since I just started iOS programming 1 month ago, I could be wrong. So please guide me.

Thanks again everyone

Upvotes: 1

Views: 1402

Answers (2)

Moinuddin Girach
Moinuddin Girach

Reputation: 223

Instead of delete row delete object from the array and reload table

- (void) tableView:( UITableView *) tableView commitEditingStyle:( UITableViewCellEditingStyle) editingStyle forRowAtIndexPath:( NSIndexPath *) indexPath {
if (editingStyle == UITableViewCellEditingStyleDelete) {

    NSArray *items = [[G5SharedStore sharedStore]allCoords];
    G5SharedStore *item = items[indexPath.row];
    [[G5SharedStore sharedStore]removeItem:item];

    //Remove this
    [tableView deleteRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationFade];

    //Add This Line
    [tableView reloadData];
}

}

Upvotes: 0

trojanfoe
trojanfoe

Reputation: 122391

I can see two problems:

Firstly this article recommends modifying the table view before the data-model (you are doing it the other way round):

It must do two things:

Send deleteRowsAtIndexPaths:withRowAnimation: or insertRowsAtIndexPaths:withRowAnimation: to the table view to direct it to adjust its presentation.

Update the corresponding data-model array by either deleting the referenced item from the array or adding an item to the array.

Secondly you don't appear to be calling beginUpdates and endUpdates around that call. To quote the reference:

Note the behavior of this method when it is called in an animation block defined by the beginUpdates and endUpdates methods.

Upvotes: 1

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