输入框不允许输入Emoji表情

在开发过程中，由于各种问题很可能会出现这种需求：
输入框不允许输入emoji表情

- (BOOL)textView:(UITextView )textView shouldChangeTextInRange:(NSRange)range replacementText:(NSString)text
 {
 //不允许输入emoji表情
 if ([textView isFirstResponder])
 {
 if ([[[textView textInputMode] primaryLanguage] isEqualToString:@"emoji"] || ![[textView textInputMode] primaryLanguage])
 {
 MBProgressHUD *hud = [MBProgressHUD showHUDAddedTo:self.view animated:YES];
 hud.mode = MBProgressHUDModeText;
 hud.label.text = @"评论不支持输入emoji表情";
 [hud hideAnimated:YES afterDelay:1.f];
 return NO;
 }
 }
 return YES;
 }