UITextField - Add a character/s after 1st character is entered while typing

Question

I have a UITextField which will contain height value. I want to format the value of the field while the user is typing into the UITextField. e.g. if I want to enter the value as "5 ft 10", the flow will be:

1. Enter 5
2. " ft " is appended immediately after I type 5 with leading & trailing space.

My code looks like this:

-(BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range       replacementString:(NSString *)string
{   

if ( [string isEqualToString:@""] ) return YES;

// currHeight Formatting
if ( textField == currHeight )  { 
   if (currHeight.text.length == 1) {   
        currHeight.text = [NSString stringWithFormat:@"%@ ft ", currHeight.text];    
        }
}
return YES; 
}

I am stuck at the point where I enter 5 nothing happens. I have to tap any button for the " ft " to be appended.

Can I do this without tapping anything?

+1 @Durga. Also see http://stackoverflow.com/questions/2198067/using-textfieldshouldchangecharactersinrange-how-do-i-get-the-text-including — HDdeveloper, Feb 27 '13 at 12:08

score 6 · Accepted Answer · edited May 23 '17 at 12:32

-shouldChangeCharactersInRange gets called before the change to the text field takes place, so the length is still 0 (see Using `textField:shouldChangeCharactersInRange:`, how do I get the text including the current typed character?). Try this instead:

- (BOOL)textField:(UITextField*)textField shouldChangeCharactersInRange:(NSRange)range
replacementString: (NSString*) string {
    if (textField == currHeight) {
        NSString *text = [textField.text stringByReplacingCharactersInRange:range
        withString: string];
        if (text.length == 1) { //or probably better, check if int
            textField.text = [NSString stringWithFormat: @"%@ ft ", text];
            return NO;
        }
    }
    return YES;
}

Thanks @lseidman. Appreciate the answer. It worked perfectly. — Durga Prasad Sahoo, May 06 '12 at 16:45

score 1 · Answer 2 · answered May 06 '12 at 15:50

When this function is called, currHeight.text still has length 0. The text only updates to 5 after you return YES.

The way to do what you want to do is test if currHeight.text.length is 0, string.length is 1 and the first character of string is numeric.

UITextField - Add a character/s after 1st character is entered while typing

2 Answers2