newSize = [_cell.detailedTextView sizeThatFits:CGSizeMake(CGRectGetWidth(_cell.detailedTextView.bounds), CGRectGetHeight(_cell.detailedTextView.bounds))];

+ (CGFloat)gettextViewHeight:(UITextView*)textView
  {
     CGSize constraint = CGSizeMake(textView.frame.size.width, 20000.0f);
     CGSize size;

      NSStringDrawingContext *context = [[NSStringDrawingContext alloc] init];
      CGSize boundingBox = [textView.text boundingRectWithSize:constraint
                                              options:NSStringDrawingUsesLineFragmentOrigin
                                           attributes:@{NSFontAttributeName:textView.font}
                                              context:context].size;

      size = CGSizeMake(ceil(boundingBox.width), ceil(boundingBox.height));

      return size.height;
  }

func height(of string: String, in textView: UITextView) -> CGFloat
{
    let font = textView.font ?? UIFont.preferredFont(forTextStyle: .headline)
    let width = textView.bounds.size.width - 2.0 * textView.textContainer.lineFragmentPadding
    let size = CGSize(width: width,
                      height: CGFloat.greatestFiniteMagnitude)
    let height = string.boundingRect(with: size,
                                     options: [.usesLineFragmentOrigin, .usesFontLeading],
                                     attributes: [NSAttributedString.Key.font: font],
                                     context: nil).size.height
    let insets = textView.textContainerInset.top + textView.textContainerInset.bottom
    let diff = ceil(font.ascender - font.capHeight)
    return height + insets + diff
}