没有特殊字符的 UITextfield 限制 ios objective c

Question

我有一个 UITextField，其中不允许使用特殊字符以及最多 20 个字符长度。

我正在使用以下代码来限制文本字段

NSUInteger newLength = [textField.text length] + [string length] - range.length;
return (newLength > limitPassportNumber) ? NO : YES;

为了停止特殊字符输入，我有以下代码。

NSCharacterSet *cs = [[NSCharacterSet characterSetWithCharactersInString:ACCEPTABLE_CHARACTERS] invertedSet];
        NSString *filtered = [[string componentsSeparatedByCharactersInSet:cs] componentsJoinedByString:@""];
        return [string isEqualToString:filtered];

现在，如果我需要 return 两个，那么只会执行一个。

有人可以指教一下吗。谢谢

Answer 1

NSString *str = @"[~!@#$%^&*()_+-]";

NSPredicate *emailTest = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", str];

if([[str evaluateWithObject:textfield.text]== YES] && [textfield.text length]<20){

  // Do Something
}
else{

  //Textfield has a special character or the text is greater than 20
}

Answer 2

检查长度。如果太长，return NO。否则检查字符是否有效。

您检查有效字符的代码效率很低。拆分并重新连接整个字符串并不是检查它是否包含任何无效字符的好方法。

以下代码是处理您的案例的更好方法：

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
    NSUInteger newLength = textField.text.length + string.length - range.length;
    if (newLength > limitPassportNumber) {
        return NO; // too long
    }

    NSCharacterSet *cs = [[NSCharacterSet characterSetWithCharactersInString:ACCEPTABLE_CHARACTERS] invertedSet];
    NSRange badRange = [string rangeOfCharacterFromSet:cs];

    return badRange.location == NSNotFound;
}

Answer 3

-(BOOL)isValidString:(NSString *)string{
    NSString *regex = @"[A-Z0-9a-z]*";
    NSPredicate *regTest = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", regex];
    if ([regTest evaluateWithObject:string]) {
        return YES;
    }
    return NO;
}

-(BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string{
    if ([string length] == 0)
        return YES;
    if ([string length] > 0 && [string length] <=20) {
        NSString *newString = [textField text];
        newString = [newString stringByReplacingCharactersInRange:range withString:string];

        return [self isValidString:newString];
    } else {
        return NO;
    }
}

没有特殊字符的 UITextfield 限制 ios objective c

UITextfield limit with no special charecters ios objective c

objective-c

uitextfield

ios