UITextView根据内容适应大小

- (void)textViewDidChange:(UITextView *)textView
{
CGFloat fixedWidth = textView.frame.size.width;
CGSize newSize = [textView sizeThatFits:CGSizeMake(fixedWidth, MAXFLOAT)];
CGRect newFrame = textView.frame;
newFrame.size = CGSizeMake(fmaxf(newSize.width, fixedWidth), newSize.height);
textView.frame = newFrame;
}

let fixedWidth = textView.frame.size.width
textView.sizeThatFits(CGSize(width: fixedWidth, height: CGFloat.max))
let newSize = textView.sizeThatFits(CGSize(width: fixedWidth, height: CGFloat.max))
var newFrame = textView.frame
newFrame.size = CGSize(width: max(newSize.width, fixedWidth), height: newSize.height)
textView.frame = newFrame;

textview.scrollEnabled = NO;