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

Here is Swift solution:

In viewDidLoad set the delegate:

_yourTextField.delegate = self

let _acceptableCharacters = "0123456789."

func textField(textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool {

    if (string.characters.count == 0) {
        return true
    }

    if (textField == self._yourTextField) {
        let cs = NSCharacterSet(charactersInString: self._acceptableCharacters)
        let filtered = string.componentsSeparatedByCharactersInSet(cs).filter {  !$0.isEmpty }
        let str = filtered.joinWithSeparator("")

        return (string != str)
    }

    return true
}

Answer 2

Objective C

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
{
    if (!string.length) 
        return YES;

    if (textField == self.tmpTextField)
    {
        NSString *newString = [textField.text stringByReplacingCharactersInRange:range withString:string];
        NSString *expression = @"^([0-9]+)?(\\.([0-9]{1,2})?)?$";
        NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:expression 
                                                                               options:NSRegularExpressionCaseInsensitive 
                                                                                 error:nil];
        NSUInteger numberOfMatches = [regex numberOfMatchesInString:newString
                                                            options:0
                                                              range:NSMakeRange(0, [newString length])];        
        if (numberOfMatches == 0)
            return NO;        
    }
    return YES;
}

Swift 3.0

func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
    if !string.characters.count {
        return true
    }
    do {
        if textField == self.tmpTextField {
            var newString = textField.text.replacingCharacters(inRange: range, with: string)
            var expression = "^([0-9]+)?(\\.([0-9]{1,2})?)?$"
            var regex = try NSRegularExpression(pattern: expression, options: NSRegularExpressionCaseInsensitive)
            var numberOfMatches = regex.numberOfMatches(inString: newString, options: [], range: NSRange(location: 0, length: newString.characters.count))
            if numberOfMatches == 0 {
                return false
            }
        }
    }
    catch let error {
    }
    return true
}