从 UITableView 中删除单元格 - 错误

Question

In my iPhone app, I have a UITableView with the following method

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
    return [tableArrays count];
}

Note that tableArrays is a class variable (an NSMutableArray of NSMutableArrays - representing one NSMutableArray for each section in my tableView). Now, that UITableView supports editing, and I have the following method

- (void)tableView:(UITableView *)theTableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath {
    ...some code...

    NSLog(@"tableArrays count is %i",[tableArrays count]);
    [tableArrays removeObjectAtIndex:indexPath.section];
    NSLog(@"tableArrays is now %@",tableArrays);
    NSLog(@"tableArrays count is now %i",[tableArrays count]);


   [tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade];

}

So, I run the app and I have two sections in my table view. Row deletion works fine except when I delete the last row in a section. When I delete the last row of section 1, I see the following output, as per the code above:

tableArrays count is 2
tableArrays is now (("Blah1","Blah2"))
tableArrays count is now 1

So clearly, my tableArrays count decreases by one, but I get the following error:

...The number of sections contained in the tableView after the update (1) must be qual to the number of sections contained in the table view before the update (2), plus or minus the number of sections inserted or dleted (0 inserted, 0 deleted).'

Answer 1

I guess in -(NSInteger)numberOfSectionsInTableView:(UITableView *)tableView; you are returning the total count of objects and you want to display only one section.

Try returning one in this method.

You should also return [tableArrays count] in -(NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section; .

It should work better like this. Also what is section in

[tableArrays removeObjectAtIndex:section]; ? Did you mean indexPath.section ?

Thank for the comment, so the method that is returning the number of section is correct, but you to do like that to delete a cell.

NSLog(@"tableArrays count is %i",[tableArrays count]);
NSMutableArray *sectionArray = [tableArrays objectAtIndex:indexPath.section];
[sectionArray removeObjectAtIndex:indexPath.row];
//[tableArrays removeObjectAtIndex:indexPath.section];
NSLog(@"tableArrays is now %@",tableArrays);
NSLog(@"tableArrays count is now %i",[tableArrays count]);

Answer 2

The key is to use

[tableView deleteSections:[NSIndexSet indexSetWithIndex:indexPath.section] withRowAnimation:UITableViewRowAnimationFade];

when you are trying to delete the last row in a section.