Is there any way to filter copied text/string into `UITextField`?
I already tried to use `UITextField` method `shouldChangeCharactersInRange`, but it only filter when we type in it, but when we paste to it, it still can't be filtered. I want `UITextField` only can input by alphanumeric, but it still can input by other char via copy paste.

here is a piece of my code

```
- (BOOL)textField:(UITextField *)textField shouldChangeCharactersInRange:(NSRange)range replacementString:(NSString *)string  {
if (textField == _nameField) {
NSCharacterSet *cs = [[NSCharacterSet characterSetWithCharactersInString:NAME_CHARACTERS] invertedSet];
NSString *filtered = [[string componentsSeparatedByCharactersInSet:cs] componentsJoinedByString:@""];
return [string isEqualToString:filtered];
}

```

Thanks in advance.