Navigation component + ToolBar + Drawer (Navigation icon click behavior and animation fix)

NavComponent.kt

private var navController: NavController? = null

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.activity_main)
    setNavigationAndToolBar()
}

private fun setNavigationAndToolBar() {
    setSupportActionBar(toolbar)
    supportActionBar?.setDisplayShowTitleEnabled(false)
      
    navController = findNavController(R.id.nav_host_fragment)
    navController?.let { navController ->
        // The set of destinations by id considered at the top level of your information hierarchy.
        // The Up button will not be  displayed when on these destinations.
        appBarConfiguration = AppBarConfiguration(
           setOf(R.id.splashFragment, R.id.homeFragment),
               drawerLayout
           )
        NavigationUI.setupActionBarWithNavController(this, navController, appBarConfiguration!!)
    }
    
    fixNavigationIconBehavior()
    setDrawerListener()
}

private fun fixNavigationIconBehavior() {
    toolbar.setNavigationOnClickListener {
        if (drawerLayout.isDrawerOpen(GravityCompat.START)) {
            drawerLayout.closeDrawer(GravityCompat.START)
        } else {
            if ((toolbar.navigationIcon as DrawerArrowDrawable).progress == 1.0f) {
                navController?.navigateUp()
            } else {
                drawerLayout.openDrawer(GravityCompat.START)
            }
        }
    }
}

private fun setDrawerListener() {
    drawerLayout.addDrawerListener(object : DrawerLayout.SimpleDrawerListener() {
        override fun onDrawerSlide(drawerView: View, slideOffset: Float) {
            toolbar.navigationIcon as DrawerArrowDrawable).progress = slideOffset
        }
    })
}

override fun onBackPressed() {
    when {
        drawerLayout.isDrawerOpen(GravityCompat.START) -> drawerLayout.closeDrawer(GravityCompat.START)
        else -> super.onBackPressed()
    }
}