Inflating toolnbar as a fragement

HomeActivity.kt

private fun showToolbarContent(isAuthenticated: Boolean, destinationId: Int) {

        val content = when (destinationId) {
            R.id.homeFragment -> if (isAuthenticated) FeedbackFragment() else CountdownFragment()
            R.id.feedFragment -> TitleFragment().also {
                val args = Bundle()
                args.putString("title", getString(R.string.feed))
                it.arguments = args
            }
            R.id.sessionsFragment -> TitleFragment().also {
                val args = Bundle()
                args.putString("title", getString(R.string.sessions))
                it.arguments = args
            }
            R.id.aboutFragment -> TitleFragment().also {
                val args = Bundle()
                args.putString("title", getString(R.string.about))
                it.arguments = args
            }
            else -> null
        }

        content?.let {
            val ft: FragmentTransaction = supportFragmentManager.beginTransaction()
            if (supportFragmentManager.fragments.size > 0)
                ft.replace(toolbarContent.id, content).commit()
            else ft.add(toolbarContent.id, content).commit()
        }
    }