Question

i can successfuly delete data from tableview , but when i go to main menu and come back then i see all the old data,

how to make data consistent , i.e once deleted it will be gone forever

- (void)viewDidLoad
{
    [super viewDidLoad];
    appDelegate = (DatabaseTestAppDelegate *)[[UIApplication sharedApplication] delegate];

        {
     appDelegate.favDetail = [[NSMutableArray alloc] initWithObjects:@"1", @"2",@"4",nil];
        }

}


- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *CellIdentifier = @"Cell";

    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    if (cell == nil) {
        cell = [[[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier] autorelease];
    }

    appDelegate = (DatabaseTestAppDelegate *)[[UIApplication sharedApplication] delegate];



     NSString *cc=[appDelegate.favDetail objectAtIndex:indexPath.row];
    NSLog(@" vale is %d",indexPath.row);
    // Configure the cell...
     NSArray *theParameters = [cc componentsSeparatedByString:@","];



    NSLog(@"array is %@",cc);
          NSLog(@"arraytheParameters is %@",theParameters);

    cell.text=cc;//theParameters;
    return cell;
}



// Override to support editing the table view.
- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath
{   NSLog(@"matrix is her%@",appDelegate.favDetail);
    if (editingStyle == UITableViewCellEditingStyleDelete) {
        // Delete the row from the data source



        [appDelegate.favDetail removeObjectAtIndex: indexPath.row];
        [tableView beginUpdates];
        [self.tableView deleteRowsAtIndexPaths:[NSArray arrayWithObject: indexPath] withRowAnimation:UITableViewRowAnimationFade];
        [tableView endUpdates];
    }   

     /*
    else if (editingStyle == UITableViewCellEditingStyleInsert) {
        // Create a new instance of the appropriate class, insert it into the array, and add a new row to the table view
    } */


}



- (void)viewWillAppear:(BOOL)animated
{ [tableView reloadData];
    [super viewWillAppear:animated]; // no use , it shows old data
}

thanks

Answer 1

If you are looking to save the state of your model beyond the life of your table view controller, there are few things you can do. One is to write the array to a file in the documents directory and read it back on reload. This would work well will small sets of data. But if you are going to use a large data set, you have to use Core Data.

As for this specific case, you are reinitializing the data on every viewDidLoad. I suggest you do this in viewDidLoad –

...
if ( appDelegate.favDetail == nil ) {
    appDelegate.favDetail = [[NSMutableArray alloc] initWithObjects:@"1", @"2",@"4",nil];
}
...

This will make sure that you don’t reinitialize it.