objective-c - 验证 UITextField 中的字母数字值

Question

我想在文本字段中输入字母数字值。如果用户只输入字符或数字，然后发送消息。甚至不接受特殊字符。

        NSString *str = askIdTxt.text;
        NSCharacterSet *alphanumericSet = [NSCharacterSet alphanumericCharacterSet];
        NSCharacterSet *numberSet = [NSCharacterSet decimalDigitCharacterSet];
        BOOL isAlphaNumericOnly = [[str stringByTrimmingCharactersInSet:alphanumericSet] isEqualToString:@""] && ! [[str stringByTrimmingCharactersInSet:numberSet] isEqualToString:@""];
        if (isAlphaNumericOnly) {
             NSLog(@"isAplhaNumericOnly: %@",(isAlphaNumericOnly? @"Yes":@"No"));
        }

这总是返回真。我不明白这有什么问题。

Answer 1

如何使用正则表达式:

-(BOOL)isAlphaNumericOnly:(NSString *)input 
{
    NSString *alphaNum = @"[a-zA-Z0-9]+";
    NSPredicate *regexTest = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", alphaNum];

    return [regexTest evaluateWithObject:input];
}

然后使用它

if([self isAlphaNumeric:str])
{
    NSLog(@"IT IS ALPHA NUMERIC STRING");

}

编辑可以使用相同的技术来验证密码，您只需要更好的正则表达式:

-(BOOL)isPasswordStrong:(NSString *)password {
/*
8-20 chars
at least one letter
at least one number OR special character
no more than 3 repeated characters
*/
        NSString *strongPass= @"^(?!.*(.)\\1{3})((?=.*[\\d])(?=.*[A-Za-z])|(?=.*[^\\w\\d\\s])(?=.*[A-Za-z])).{8,20}$";;
        NSPredicate *regexTest = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", strongPass];

        return [regexTest evaluateWithObject:password];
}

使用正则表达式，您可以创建不同的规则，但这可以让您抢先一步，