Allow only 2 whitespace in text

Question

I have a UITextField and I want to allow user enter in this field maximum 2 whitespace. How I can do it?

I think I need to check something here:
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {}

But what to check? I have searched the web, but nothing found.

Answer 1

This will return how many spaces there are in the string

 - (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
    int numberOfSpaces = [[textField.text componentsSeparatedByString:@" "] count];

    if (numberOfSpace > 2) {

        //notify user that he/she has too many spaces

    }
}

Also you seem new to iOS. Don't forget to set your view controller as a UITextField delegate.

Answer 2

You want to use a regular expression for this. The expression \s\s+ means two or more spaces, carriage returns or tabs.

NSString *text = textField.text;
NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:
                              @"(\s\s+)" options:0 error:nil];

[regex replaceMatchesInString:str options:0 range:NSMakeRange(0, [str length]) withTemplate:@"  "];    
textField.text = text;