Will disabling UIAlertView buttons get my app rejected?

Question

I'm using an AlertView with a UITextView subview to let users reply to posts in my app, but I want the Reply button of the alert to disable when the user types more than the character limit. Will disabling the alert view button like this get my app rejected, is there a better way to do this?

-(void)textViewDidChange:(UITextView *)textView {
    if (!replyAlert) {
        return;
    }

    //character count
    replyAlert.title = [NSString stringWithFormat:@"Reply to Post (%i/250)", [textView.text length]];
    if ([textView.text length]>=250) {
        //disable alert view button
        for (UIView* view in [replyAlert subviews])
        {
            if ([[[view class] description] isEqualToString:@"UIAlertButton"])
            {
                UIButton *button = (UIButton*)view;
                if ([button.titleLabel.text isEqualToString:@"Reply"]) {
                    //disable
                    button.enabled = NO;
                }
            }
        }
    } else if ([textView.text length]==249) {
        //re-enable button if user deleted a character
        for (UIView* view in [replyAlert subviews])
        {
            if ([[[view class] description] isEqualToString:@"UIAlertButton"])
            {
                UIButton *button = (UIButton*)view;
                if ([button.titleLabel.text isEqualToString:@"Reply"]) {
                    //enable
                    button.enabled = YES;
                }
            }
        }
    }
}

Answer 1

Have a look at this method on the delegate (UIAlertViewDelegate)

- (BOOL)alertViewShouldEnableFirstOtherButton:(UIAlertView *)alertView

This method will be called each time a user types a character into a text field in the alert view, assuming you are using the UIAlertViewStylePlainTextInput (?). So in this method you could check the length of the text in the text field and return TRUE/FALSE accordingly.

The method is only available in iOS 5.0 or later too which may be an issue if supporting older versions.

If you are adding your own text fields as subviews to the alert view, then this alone is cause for the app to be rejected as it states that the view hierarchy is not to be manipulated. If you are using the text input style alert view out-of-the-box and just navigating the subviews to check the button titles and disable them, I'd be surprised (note this is a subjective opinion) if that caused a rejection of the app.