iphone - 使用特殊字符验证文本字段

Question

在我的应用程序中。我想用特殊字符验证文本字段，

前任。如果用户按？从键盘比用户无法输入？在文本字段中，

请任何人建议，我该怎么做？

Answer 1

像下面这样尝试它会帮助你。它只接受字母

   - (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string
    {
        //For avoiding user to enter non digital number..
        if([[string stringByTrimmingCharactersInSet:[[NSCharacterSet letterCharacterSet] invertedSet]] isEqualToString:@""])
        {
            return NO;
        }
        else
        {
            return YES;
        }
    }

Answer 2

检查这个

利用

- (BOOL) textField:(UITextField*)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString*)textEntered

Answer 3

看看这是否有效：

    -(NSString *) formatIdentificationNumber:(NSString *)string
     {
       NSCharacterSet * invalidNumberSet = [NSCharacterSet characterSetWithCharactersInString:@"\n_!@#$%^&*()[]{}'\".,<>:;|\\/?+=\t~` "];

    NSString  * result  = @"";
    NSScanner * scanner = [NSScanner scannerWithString:string];
    NSString  * scannerResult;

    [scanner setCharactersToBeSkipped:nil];

     while (![scanner isAtEnd])
     {
    if([scanner scanUpToCharactersFromSet:invalidNumberSet intoString:&scannerResult])
    {
        result = [result stringByAppendingString:scannerResult];
    }
    else
    {
        if(![scanner isAtEnd])
        {
            [scanner setScanLocation:[scanner scanLocation]+1];
        }
    }
 }

  return result;
  }