How can I remove rows from a UITableView with animation?
I am having problems deleting rows from a table view. I am using below code when delete button was clicked in line:
NSIndexPath *indexPath = [NSIndexPath indexPathForRow:control.tag-100 inSection:0];
[resultList removeObjectAtIndex:indexPath.row];
[resultView beginUpdates];
[resultView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationAutomatic];
[resultView endUpdates];
//[resultView reloadData];
The first line was deleted successfully, but then the indices were incorrect. So when I remove the last row it gives an out of bounds index exception.
Cell Generation Code:
- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *CellIdentifier = @"personalizeTableCell";
PersonalizeCell *cell = (PersonalizeCell *)[tableView dequeueReusableCellWithIdentifier:CellIdentifier];
if (cell == nil)
cell = [[PersonalizeCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
cell.title.text = @"text";
cell.rateView.tag = indexPath.row + 100;
return cell;
}
Where am I going wrong?
UPDATE:
for (NSInteger j = 0; j < [venuesTableView numberOfSections]; ++j)
{
for (NSInteger i = 0; i < [venuesTableView numberOfRowsInSection:j]; ++i)
{
PersonalizeCell* cell = (PersonalizeCell*)[venuesTableView cellForRowAtIndexPath:[NSIndexPath indexPathForRow:i inSection:j]];
cell.rateView.tag = 100 + i;
}
}
solved my problem. Thanks to Nenad M.
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Assuming yours is [NSIndexPath indexPathForRow:control.tag-100 inSection:0];
returning the correct index path .... Have you tried moving the call removeObjectAtIndex
inside the "start / end update" bracket ?:
NSIndexPath *indexPath = [NSIndexPath indexPathForRow:control.tag-100 inSection:0];
[resultView beginUpdates];
[resultList removeObjectAtIndex:indexPath.row];
[resultView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationAutomatic];
[resultView endUpdates];
UPDATE:
Obviously yours cell.rateView.tag
will become incorrect after you delete the first cell. So after every delete (i.e. every removeObjectAtIndex...
) you have to iterate over the remaining tableview cells to re-assign the correct tag value ( cell.rateView.tag = indexPath.row + 100
)! Otherwise, yours [NSIndexPath indexPathForRow:control.tag-100 inSection:0];
will return the wrong index patch, therefore leading to your error out of bounds!
Reassigning tag values:
You don't need to reload the whole table, just iterate over the remaining cells reassigning the tag value after [resultView endUpdates];
:
NSMutableArray *cells = [[NSMutableArray alloc] init];
for (NSInteger j = 0; j < [tableView numberOfSections]; ++j)
{
for (NSInteger i = 0; i < [tableView numberOfRowsInSection:j]; ++i)
{
[cells addObject:[tableView cellForRowAtIndexPath:[NSIndexPath indexPathForRow:i inSection:j]]];
}
}
Now run:
for (PersonalizeCell* cell in cells)
{
cell.rateView.tag = // new calculated tag
}
(Or re-assignment even in the inner loop of the first piece of code).
Here is some really typical code for the whole process, two lines from the table in the example:
Please note that facebookRowsExpanded is a class variable that you must have:
if ( [theCommand isEqualToString:@"fbexpander"] )
{
NSLog(@"expander button......");
[tableView deselectRowAtIndexPath:indexPath animated:NO];
NSArray *deleteIndexPaths;
NSArray *insertIndexPaths;
facebookRowsExpanded = !facebookRowsExpanded;
// you must do that BEFORE, not AFTER the animation:
if ( !facebookRowsExpanded ) // ie, it was just true, is now false
{
deleteIndexPaths = [NSArray arrayWithObjects:
[NSIndexPath indexPathForRow:2 inSection:0],
[NSIndexPath indexPathForRow:3 inSection:0],
nil];
[tableView beginUpdates];
[tableView
deleteRowsAtIndexPaths:deleteIndexPaths
withRowAnimation: UITableViewRowAnimationMiddle];
[tableView endUpdates];
}
else
{
insertIndexPaths = [NSArray arrayWithObjects:
[NSIndexPath indexPathForRow:2 inSection:0],
[NSIndexPath indexPathForRow:3 inSection:0],
nil];
[tableView beginUpdates];
[tableView
insertRowsAtIndexPaths:insertIndexPaths
withRowAnimation: UITableViewRowAnimationMiddle];
[tableView endUpdates];
}
// DO NOT do this at the end: [_superTableView reloadData];
return;
}
NOTE: your code for numberOfRowsInSection must use facebookRowsExpanded
(it will be something like "if facebookRowsExpanded return 7, else return 5")
NOTE: your code for cellForRowAtIndexPath must use facebookRowsExpanded.
(it should return the correct string, depending on whether it expands or not.)
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