1

我想将用户名字段的输入限制为仅限英文字母（az）。有人可以帮我添加到下面的代码中，以不允许输入除英文字母之外的任何数字、字符和任何其他语言吗？

现在下面的代码不允许空格，也不允许输入超过 10 个字母。

- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string {
{
    BOOL _isAllowed = YES;
    NSString *nameRegex = @"[A-Za-z]+";
    NSPredicate *nameTest = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", nameRegex];

    NSString *tempString = [[textField.text stringByReplacingCharactersInRange:range withString:string] stringByTrimmingCharactersInSet:[NSCharacterSet whitespaceAndNewlineCharacterSet]];



    if (textField == self.usernameField)
    {
        if ([self.usernameField.text isEqualToString:tempString])
        {
            self.title.text = @"No Spaces Allowed";
            self.title.textColor = [UIColor yellowColor];

            _isAllowed =  NO;
        }

        else if (tempString.length > 10)
        {
            self.title.text = @"Username cannot be more than 10 letters.";
            self.title.textColor = [UIColor yellowColor];

            _isAllowed =  NO;
        }

更新：

        else if (![nameTest evaluateWithObject:self.usernameField.text])
        {
                self.title.text = @"Username can only contain english letters.";
                self.title.textColor = [UIColor yellowColor];

                _isAllowed =  NO;
        }
        return   _isAllowed;
    }

    return   _isAllowed;
}

谢谢。

4

1 回答 1

7

您可以使用此正则表达式来检查用户名是否仅包含英文字母：

NSString *nameRegex = @"[A-Za-z]+";
NSPredicate *nameTest = [NSPredicate predicateWithFormat:@"SELF MATCHES %@", nameRegex];

if(![nameTest evaluateWithObject:self.usernameField.text]){
        self.title.text = @"Username can only contain english letters.";
        self.title.textColor = [UIColor yellowColor];

        _isAllowed =  NO;
}
于 2013-03-13T17:18:05.880 回答