UITextField Should accept number only values

Question

I have UITexfields i want that it should accept only number other shows alert that enter a numeric value. I want that motionSicknessTextFiled should only accept number

Answer 1

I just modified the answer of Michael and made it a little bit easier to implement. Just make sure that the delegate of your UITextfield is set to itself.

yourTxtField.delegate = self;

Furthermore copy & paste this code into your main file.

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

    if (textField == yourTxtField) {
        NSCharacterSet *numbersOnly = [NSCharacterSet characterSetWithCharactersInString:@"0123456789"];
        NSCharacterSet *characterSetFromTextField = [NSCharacterSet characterSetWithCharactersInString:string];

        BOOL stringIsValid = [numbersOnly isSupersetOfSet:characterSetFromTextField];
            return stringIsValid;
        }else {
            return YES;
        }
    }

If you want to allow the use of the spacebar just put in a blank space at the end of the CharactersInString, just like so:

@"0123456789" -> @"0123456789 "

Additionally:

If you want to restrict the length of the string just replace the if-function with following:

if (textField == yourTxtField) {
        NSUInteger newLength = [textField.text length] + [string length] - range.length;
        NSCharacterSet *cs = [[NSCharacterSet characterSetWithCharactersInString:@"1234567890"] invertedSet];
        NSString *filtered = [[string componentsSeparatedByCharactersInSet:cs] componentsJoinedByString:@""];
        return (([string isEqualToString:filtered])&&(newLength <= 10));

    }

In my case the "10" at the end represents the limit of characters.

Cheers! :)