Question

I am a novice in Programming and have just started Objective C. I have created a text field in which I want to allow a “.” to be entered only once! From what I understand, rangeOfString should be able to do this.

-(IBAction)floatingPoint:(UIButton *) sender {

    NSString *floatingPoint = [sender currentTitle];
    NSRange range = [floatingPoint rangeOfString:@"."];

    if (range.location == NSNotFound) {
        self.display.text = 
            [self.display.text stringByAppendingString:floatingPoint];
    }
}

From what I understand the code floatingPoint rangeOfString:@”.” would check for “.” in currentTitle and if it is not found should append this string with a “.”

But this is not happening, no decimal point is being entered. If I enter only
self.display.text = [self.display.text stringByAppendingString:floatingPoint];
then the text field allows more than 1 decimal points to be entered.
Sorry if I described the problem incorrectly, I am new to all this stuff and this has just begun to sink in.

Answer 1

You’re checking the button’s title for a .. You probably set the button’s title to . in your nib, so of course it always contains a .!

You need to check your text field’s text for a . instead. Try this:

NSRange range = [self.display.text rangeOfString:floatingPoint];