如何限制UITextField中除点和下划线之外的特殊字符？

Question

如何限制UITextField中除点和下划线之外的特殊字符？

我尝试了下面的代码片段，但运气不好：

#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;
        }
}

Answer 1

雨燕4

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

UITextField委托方法：

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
}

Answer 2

试试这个

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

你可以自己做一套

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

Answer 3

试试下面给出的代码块，它对我来说很好。

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)
}

目标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];
}

希望它也能对你起作用。