行删除后如何对表格视图数字字符串进行数字排序

Question

I have a table view that adds rows on a button press. The rows are numbered from a string itmeNo in ascending order for each row. My problem is when user deletes a row, the numbers are no longer in order.

ie 1,2,3,4,5,

if user deletes row 3and 4 they are numbered

1,2,5

Im a bit stuck on how to sort numerically? where I have [self.observations count] + 1]; can I change this perhaps so itemNo always sorts ascending numerically

In summary I always want my table view rows number string to always be sequentially numbered

A bit of reach but so far ive tried [self.tableView reloadData]; in the delete method and playing around with method allowing re ordering of table view.

 - (void)addObservationButtonPressed:(id)sender
{
LogCmd();
Observation *observation = [[ICObservationManager manager] newObservation];
observation.createdAt = [NSDate date];
observation.modifiedAt = [NSDate date];
observation.certificate = self.certificate;
observation.itemNo = [NSString stringWithFormat:@"%d", [self.observations count] + 1];
[self.certificate addObservationsObject:observation];
[self loadData];
[self.tableView reloadData];
[self.tableView scrollToRowAtIndexPath:[NSIndexPath indexPathForRow:self.observations.count-1 inSection:0] atScrollPosition:UITableViewScrollPositionBottom animated:YES];
}


 - (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
 {
return [self.certificate.observations count];
}



 - (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
static NSString *cellIdentifier = @"ObservationsCellIdentifier";
UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier];
if (cell == nil) {
    cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:cellIdentifier];
}
Observation *observation = [self.observations objectAtIndex:indexPath.row];
NSString *itemLabel = [NSString stringWithFormat:@"%@. %@",
                       observation.itemNo,
                       (observation.item.length ? observation.item : @"No description")];
cell.textLabel.text = itemLabel;

return cell;
}

 //Delete observations

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

if (editingStyle == UITableViewCellEditingStyleDelete) {
    [self.managedObjectContext deleteObject:[self.observations objectAtIndex:indexPath.row]];
    [self.appDelegate saveContext];
    [self.observations removeObjectAtIndex:indexPath.row];
    [tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject:indexPath] withRowAnimation:UITableViewRowAnimationFade];

 }

}

Answer 1

Here is code :-

Observation *observation = [self.observations objectAtIndex:[self.observations count]-1];
int lastValue = [observation.itemNo intValue];
lastValue++;

lastValue is max value you can use

Hope it helps you

Answer 2

Try this code

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

if (editingStyle == UITableViewCellEditingStyleDelete) {
    [self.managedObjectContext deleteObject:[self.observations objectAtIndex:indexPath.row]];
    [self.appDelegate saveContext];
    [self.observations removeObjectAtIndex:indexPath.row];

//need to add these lines
 NSSortDescriptor *sortByUploaded =[NSSortDescriptor sortDescriptorWithKey:@"itmeNo"ascending:YES];

  NSArray *sortDescriptorArr = [NSArray arrayWithObjects:sortByUploaded,nil];

 self.observations = [NSMutableArray arrayWithArray:[self.observations sortedArrayUsingDescriptors:sortDescriptorArr]];


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

 }

}

Let me know if its not working

Answer 3

When you are deleting rows from UITableView just sort it to the order again you want as @ rohit does and then delete the row and reload your table according to order. Hope this helps.