Pass information to UIAlertView delegate

Question

I'm trying to delete a row in table view after confirmation from the user, using an alert view. However I don't know how to let the UIAlertViewDelegate method know which row in the table to delete.

// Override to support editing the table view.
- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath
{
    if (editingStyle == UITableViewCellEditingStyleDelete) {
        UIAlertView *alert_delete = [[UIAlertView alloc]initWithTitle:[NSString stringWithFormat:@"Confirm Delete %@",[names objectAtIndex:indexPath.row] ] message:@"Warning all student data will be earsed" delegate:self cancelButtonTitle:@"Dismess" otherButtonTitles:@"YES", nil];
        [alert_delete show];

        // Delete the row from the data source
        [tableView deleteRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationFade];
    } 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
    }   
}

in alert method i try handle it to delete row from table and database

    -(void) alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex{
        NSString*title = [alertView buttonTitleAtIndex:buttonIndex];
        if ([title isEqualToString:@"YES"]) {
           // how to pass indexPath.row to alertview 
             [names removeObjectAtIndex:indexPath.row];
        }


    }

Answer 1

If you want to pass something to the delegate then add a property to the delegate class and pass the information to it before invoking the alert view:

@interface AlertDelegate : NSObject <UIAlertViewDelegate>
@property (nonatomic) NSIndexPath *indexPath;
@end

// @implementation AlertDelegate omitted

And use thus:

UIAlertView *alertView = ...;
AlertDelegate *delegate = [AlertDelegate new];
alertView.delegate = delegate;
delegate.indexPath = indexPathFromSomewhere;
[alertView show];   // or whatever

If the delegate is self, then that means adding the property to self (or use a private instance variable).

In the delegate method you then have access to the indexPath:

-(void) alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex{
    NSString*title = [alertView buttonTitleAtIndex:buttonIndex];
    if ([title isEqualToString:@"YES"]) {
        [names removeObjectAtIndex:self.indexPath.row];
    }
}