Question

I’m trying to validate text length in textField. Here is what I try

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
    NSString *textLenght = [NSString stringWithFormat:@"%@", [textField text]];
    if ([textLenght length] > 5)
    {
        UIAlertView *alert = [[UIAlertView alloc]initWithTitle:@"Message" 
                                                message:@"Too long" 
                                                delegate:self 
                                                cancelButtonTitle:@"OK" 
                                               otherButtonTitles:nil, nil];
        [alert show];
        [alert release];
        return NO;
    }
    return YES;
}

This code works well. The alert box is displayed when I type more than 5 characters. The problem is that when I try to delete the last character of textfield the alert box is displayed again.

How to fix that ?

Answer 1

You have to create the actual string first

NSString *str = [textField.text stringByReplacingCharactersInRange:range withString:text];

You check the length afterwards

int length = str.length;

And continue with the if (length) checking.

This way first creates the required string (also taking into consideration the backspaces).