How can I restrict special characters in UITextField except dot and underscores?

Question

How can I restrict special characters in a UITextField except dot and underscores?

I have tried the code snippet below, but without luck:

#define ACCEPTABLE_CHARECTERS @" ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789_." - (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string { NSCharacterSet *acceptedInput = [NSCharacterSet characterSetWithCharactersInString:ACCEPTABLE_CHARECTERS]; if (![[string componentsSeparatedByCharactersInSet:acceptedInput] count] > 1){ NSLog(@"not allowed"); return NO; } else{ return YES; } }

have you tried Regular expression ??

Vinay Chopra
– Vinay Chopra

2013-01-28 08:52:56 +00:00
Commented Jan 28, 2013 at 8:52 — Vinay Chopra
– Vinay Chopra, Commented Jan 28, 2013 at 8:52
Best answer: stackoverflow.com/a/7541846/1463604

Nishant
– Nishant

2015-07-17 09:01:57 +00:00
Commented Jul 17, 2015 at 9:01 — Nishant
– Nishant, Commented Jul 17, 2015 at 9:01
FOR SWIFT... stackoverflow.com/a/26337774/294884

Fattie
– Fattie

2015-09-28 00:34:23 +00:00
Commented Sep 28, 2015 at 0:34 — Fattie
– Fattie, Commented Sep 28, 2015 at 0:34

Piyush Sanepara · Accepted Answer · 2017-11-08 07:42:22Z

Try code block given below, it worked fine for me.

SWIFT 3.0

let ACCEPTABLE_CHARACTERS = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789_" func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool { let cs = NSCharacterSet(charactersIn: ACCEPTABLE_CHARACTERS).inverted let filtered = string.components(separatedBy: cs).joined(separator: "") return (string == filtered) }

Objective C

#define ACCEPTABLE_CHARACTERS @" ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789_." - (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string { NSCharacterSet *cs = [[NSCharacterSet characterSetWithCharactersInString:ACCEPTABLE_CHARACTERS] invertedSet]; NSString *filtered = [[string componentsSeparatedByCharactersInSet:cs] componentsJoinedByString:@""]; return [string isEqualToString:filtered]; }

Hope it will work for you as well.

@Fogh he is already using the invertedSet method so we don't need to include ! in the return statement.
Seems a bit excessive to split something up, join it back together and then see if the two match when all you really need to do is count how many components there are after the split. If there's more than one, you already know there are unwanted characters.
Swift version here, let ALLOWED_CHARS = "abcdefghijklmnopqrstuvwxyz0123456789_."; func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool { let set = CharacterSet(charactersIn: ALLOWED_CHARS); let filtered = string .components(separatedBy: set) .joined(separator: ""); return filtered != string; }
@ElegyD, you should add Swift 4 version, not replace Swift 3 version with Swift 4.

amar · Accepted Answer · 2013-01-28 08:33:39Z

Try this

NSCharacterSet *set= [NSCharacterSet symbolCharacterSet]; if ([string rangeOfCharacterFromSet:[set invertedSet]].location == NSNotFound) { // valid } else { // invalid }

you can make your own set with

NSCharacterSet *set= [NSCharacterSet characterSetWithCharactersInString:@"<all your symbols you want to ignore>"];

Change symbolCharacterSet to ACCEPTABLE_CHARECTERS and this will work how he wants....

Sunil Targe · Accepted Answer · 2018-08-08 07:10:55Z

Swift 4

let RISTRICTED_CHARACTERS = "'*=+[]\\|;:'\",<>/?%"

UITextField delegate method:

func textField(_ textField: UITextField, shouldChangeCharactersIn _: NSRange, replacementString string: String) -> Bool { let set = CharacterSet(charactersIn: RISTRICTED_CHARACTERS) let inverted = set.inverted let filtered = string.components(separatedBy: inverted).joined(separator: "") return filtered != string }

This has a bug in it that the return bool should be == and not !=. Currently it will allow all characters except the restricted.
This doesn't work for case string == "" (for example clearing input)

Sourabh Sharma · Accepted Answer · 2023-03-11 20:06:56Z

Swift 5 solution

let ACCEPTABLE_CHARACTERS = " ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789_." func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool { let cs = CharacterSet(charactersIn: ACCEPTABLE_CHARACTERS).inverted let filtered: String = (string.components(separatedBy: cs) as NSArray).componentsJoined(by: "") return (string == filtered) }

ChintaN -Maddy- Ramani · Accepted Answer · 2015-01-19 05:12:39Z

NSString *Regex = @"[A-Za-z0-9^]*";

NSPredicate *TestResult = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", Regex];

[TestResult evaluateWithObject:@"YourTestString"];

Last return boolean value true/false

In Method

+ (BOOL) validateSpecialCharactor: (NSString *) text { NSString *Regex = @"[A-Za-z0-9^]*"; NSPredicate *TestResult = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", Regex]; return [TestResult evaluateWithObject:text]; }

Community · Accepted Answer · 2017-05-23 11:47:01Z

Swift 2.2 based on Mrunal's answer:

let notAllowedCharacters = " ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789_."; func textField( textField: UITextField, shouldChangeCharactersInRange range: NSRange, replacementString string: String) -> Bool { let set = NSCharacterSet(charactersInString: notAllowedCharacters); let inverted = set.invertedSet; let filtered = string .componentsSeparatedByCharactersInSet(inverted) .joinWithSeparator(""); return filtered == string; }

@a.u.b I don't think the replacement string can ever be empty, but give it a try

SachinVsSachin · Accepted Answer · 2013-01-28 09:35:09Z

This may help you try this.. and let me know please

-(BOOL)isHaveSpecialChar:(NSString*)str{ NSString *customStr = @"~`!@#$%^&*()+=-/;:\"\'{}[]<>^?, "; NSCharacterSet *alphaSet = [NSCharacterSet characterSetWithCharactersInString:customStr]; BOOL isHaveSpecialChar = [[str stringByTrimmingCharactersInSet:alphaSet] isEqualToString:@""]; return !isHaveSpecialChar; }

This is wrong - it will only return YES if every character in str is a character in customStr.

GOWTHAM · Accepted Answer · 2016-11-02 12:50:09Z

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

Aleksey Mazurenko · Accepted Answer · 2019-03-04 12:20:13Z

func textField(_ textField: UITextField, shouldChangeCharactersIn range: NSRange, replacementString string: String) -> Bool { let cs = NSCharacterSet.decimalDigits.inverted let filtered = string.components(separatedBy: cs).joined(separator: "") return (string == filtered) }

shivam · Accepted Answer · 2013-01-28 09:10:56Z

Try this:

NSString *str = @"___asdf.SHiv._.l.asg. g.g._ASdgASG_.......asfgads.g. .._____fdgdsfghsdfgh"; str= [str stringByReplacingOccurrencesOfString:@"." withString:@""]; str=[str stringByReplacingOccurrencesOfString:@"_" withString:@""]; str=[str stringByReplacingOccurrencesOfString:@" " withString:@""]; str=[str stringByTrimmingCharactersInSet:[NSCharacterSet alphanumericCharacterSet]]; if ([str isEqualToString:@""]) { NSLog(@"valid"); } else { NSLog(@"invalid"); }

This is an extremely roundabout. Regular expressions are built for exactly this kind of thing.

Collectives™ on Stack Overflow

How can I restrict special characters in UITextField except dot and underscores?

10 Answers 10

6 Comments

1 Comment

2 Comments

Swift 5 solution

1 Comment

Comments

2 Comments

1 Comment

Comments

Comments

1 Comment

Linked

Hot Network Questions

Collectives™ on Stack Overflow

10 Answers 10

6 Comments

1 Comment

2 Comments

Swift 5 solution

1 Comment

Comments

2 Comments

1 Comment

Comments

Comments

1 Comment

Linked

Related