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

Another option of entering only numeric values into your text field is by selecting the keyboard type attribute of the corresponding textfield. Attaching the screenshot for reference.

Answer 2

[textField setKeyboardType:UIKeyboardTypeNumberPad];

Answer 3

swift 4

This allows only number input and you can also set character limitation

func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {
  let aSet = NSCharacterSet(charactersIn:"0123456789").inverted
  let compSepByCharInSet = string.components(separatedBy: aSet)
  let numberFiltered = compSepByCharInSet.joined(separator: "")

  if string == numberFiltered {
    let currentText = textField.text ?? ""
    guard let stringRange = Range(range, in: currentText) else { return false }
    let updatedText = currentText.replacingCharacters(in: stringRange, with: string)
    return updatedText.count <= 10
  } else {
    return false
  }
}

Answer 4

this is the function which checks for the String contains Numeric value only

+(BOOL) checkforNumeric:(NSString*) str
{
    NSString *strMatchstring=@"\\b([0-9%_.+\\-]+)\\b"; 
    NSPredicate *textpredicate=[NSPredicate predicateWithFormat:@"SELF MATCHES %@", strMatchstring];

    if(![textpredicate evaluateWithObject:str])
    {
        //////NSLog(@"Invalid email address found");
        UIAlertView *objAlert = [[UIAlertView alloc] initWithTitle:APP_NAME message:@"please enter valid text." delegate:nil cancelButtonTitle:nil otherButtonTitles:@"Close",nil];
        [objAlert show];
        [objAlert release];
        return FALSE;
    }
    return TRUE;
}

check it on submit button.

Answer 5

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! :)

Answer 6

Swift 4.2 port of the best answer here by @almas-adlibek

A bunch of configuration variables:

private let kMaxTextLength = 8
private let kZeroDotted = "0."
private let kZero = "0"
private let kDoubleDot = ".."
private let kDot = "."
private let kPeriod = ","

Now the Swift 4 converted part of the code.

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

    guard let oldText = textField.text, let swiftRange = Range(range, in: oldText) else {
        return true
    }

    let newText = oldText.replacingCharacters(in: swiftRange, with: string)

    var currentText =  textField.text?.trimmingCharacters(in: CharacterSet.whitespacesAndNewlines)

    // Change the "," (appears in other locale keyboards, such as russian) key ot "."
    currentText = currentText?.replacingOccurrences(of: kPeriod, with: kDot)

    // Check the statements of decimal value.
    if (newText == kDot) {
        textField.text = kZeroDotted;
        return false
    }

    if (newText.range(of: kDoubleDot) != nil) {
        textField.text = newText.replacingOccurrences(of: kDoubleDot, with: kDot);
        return false
    }

    // If second dot is typed, ignore it.
    let dots = newText.components(separatedBy: kDot)
    if(dots.count > 2) {
        textField.text = currentText;
        return false
    }

    // If first character is zero and second character is > 0, replace first with second. 05 => 5;
    if(newText.count == 2) {
        if(newText[0...0] == kZero && newText != kZeroDotted) {
            textField.text = newText[1...1]
            return false
        }
    }

    // Check the max characters typed.
    let oldLength = textField.text?.count ?? 0
    let replacementLength = string.count
    let rangeLength = range.length

    let newLength = oldLength - rangeLength + replacementLength;
    let returnKey = string.rangeOfCharacter(from: CharacterSet.newlines) != nil

    return newLength <= kMaxTextLength || returnKey;
}