检查UITextfield是否包含(?！$等)

Question

我正在执行一个条件语句，该语句检查文本字段是否包含某些字符，如果包含这些字符，则会显示UIAlertView。目前，如果文本字段包含字母，则会显示警报，我将如何扩展下面的方法以包括字符，如？！，$等

if ([self.withdrawTextField.text rangeOfCharacterFromSet:[NSCharacterSet letterCharacterSet]].location != NSNotFound) {
        UIAlertView * alert = [[UIAlertView alloc] initWithTitle:@"Ooops" message:@"Please only use numbers and the period (.)." delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil, nil];
        [alert show];
}

Answer 1

试试这个：

NSMutableCharacterSet *mcs1 = [[NSCharacterSet letterCharacterSet] mutableCopy];
 [mcs1 addCharactersInString:@"?!.$"];
if ([self.withdrawTextField.text rangeOfCharacterFromSet:mcs1].location != NSNotFound) {
        UIAlertView * alert = [[UIAlertView alloc] initWithTitle:@"Ooops" message:@"Please only use numbers and the period (.)." delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil, nil];
        [alert show];
}

Answer 2

由于您只想在字符串中使用数字和句点，因此可以尝试下面的代码。它可能会对你有所帮助。

NSCharacterSet *myCharSet = [NSCharacterSet characterSetWithCharactersInString:@"0123456789."];
for (int i = 0; i < [[self.withdrawTextField.text length]; i++) 
{
    unichar c = [string characterAtIndex:i];
    if (![myCharSet characterIsMember:c]) 
       {
        UIAlertView * alert = [[UIAlertView alloc] initWithTitle:@"Ooops" message:@"Please only use numbers and the period (.)." delegate:self cancelButtonTitle:@"OK" otherButtonTitles:nil, nil];
        [alert show];
        return;
       }
}