I want to change navigation bar color of QLPreviewController in swift 3. I have used below code to change color but its not working 

```
viewQLPreview = QLPreviewController()
viewQLPreview.dataSource = self
viewQLPreview.delegate = self
viewQLPreview.navigationController?.navigationBar.isTranslucent = false
viewQLPreview.navigationController?.navigationBar.tintColor = UIColor.red

```