How to Read Number of lines in UITextView

I am using UITextView In my View , I have requirement to count number of line contained by textview am using following function to read '\n' . However this works only when return key is pressed from keyboard , but in case line warapper (when i type continuous characters i wont get new line char ) . How do i read new char when line is changed without hitting return key ?? Anybody has nay idea how to .. please share it .. I am follwing this link Link

- (BOOL)textView:(UITextView *)textView shouldChangeTextInRange:(NSRange)range 
 replacementText:(NSString *)text
{
    // Any new character added is passed in as the "text" parameter
    if ([text isEqualToString:@"\n"]) {
        // Be sure to test for equality using the "isEqualToString" message
        [textView resignFirstResponder];

        // Return NO so that the final '\n' character doesn't get added
        return NO;
    }
    // For any other character return YES so that the text gets added to the view
    return YES;
}