How can I limit the number of decimal points in a UITextField? How can I limit the number of decimal points in a UITextField? ios ios

How can I limit the number of decimal points in a UITextField?


Implement the shouldChangeCharactersInRange method like this:

// Only allow one decimal point// Example assumes ARC - Implement proper memory management if not using.- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {    NSString *newString = [textField.text stringByReplacingCharactersInRange:range withString:string];    NSArray  *arrayOfString = [newString componentsSeparatedByString:@"."];    if ([arrayOfString count] > 2 )         return NO;    return YES;}

This creates an array of strings split by the decimal point, so if there is more than one decimal point we will have at least 3 elements in the array.


Here is an example with a regular expression, the example limits to only one decimal point and 2 decimals. You can tweak it to fit your needs.

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {    NSString *newString = [textField.text stringByReplacingCharactersInRange:range withString:string];    NSString *expression = @"^[0-9]*((\\.|,)[0-9]{0,2})?$";    NSError *error = nil;    NSRegularExpression *regex = [NSRegularExpression regularExpressionWithPattern:expression options:NSRegularExpressionCaseInsensitive error:&error];    NSUInteger numberOfMatches = [regex numberOfMatchesInString:newString options:0 range:NSMakeRange(0, [newString length])];    return numberOfMatches != 0;}


Swift 3 Implement this UITextFieldDelegate method to prevent user from typing an invalid number:

func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool {    let text = (textField.text ?? "") as NSString    let newText = text.replacingCharacters(in: range, with: string)    if let regex = try? NSRegularExpression(pattern: "^[0-9]*((\\.|,)[0-9]*)?$", options: .caseInsensitive) {        return regex.numberOfMatches(in: newText, options: .reportProgress, range: NSRange(location: 0, length: (newText as NSString).length)) > 0    }    return false}

It is working with both comma or dot as decimal separator. You can also limit number of fraction digits using this pattern: "^[0-9]*((\\.|,)[0-9]{0,2})?$" (in this case 2).


matomo