Switch between Hamburger icon and Back arrow icon in navigation drawer in spcific fragment not working

Question

I am trying to change the navigation icon when opening the settings fragment using this way and this but both not working I am still seeing the hamburger icon in the settings fragment

MainActivity

@AndroidEntryPoint
class MainActivity : AppCompatActivity(), HideShowIconInterface {

    var APP_START_TIME: Long = 0


    private lateinit var appBarConfiguration: AppBarConfiguration
    private var _binding: ActivityMainBinding? = null
    val binding get() = _binding!!
    private lateinit var navController: NavController
    private lateinit var postViewModel: PostViewModel
    private var _navGraph: NavGraph? = null
    private val navGraph get() = _navGraph!!
    lateinit var adView: AdView
    private var adRequest: AdRequest? = null


    private val applicationScope = CoroutineScope(Dispatchers.Unconfined)

    lateinit var drawerLayout: DrawerLayout

    lateinit var drawerToggle: ActionBarDrawerToggle


    override fun onDestroy() {
        super.onDestroy()

        adView.destroy()
        adRequest = null
        _binding = null
    }

    override fun onCreate(savedInstanceState: Bundle?) {

        super.onCreate(savedInstanceState)
        APP_START_TIME = System.currentTimeMillis()
        _binding = ActivityMainBinding.inflate(layoutInflater)
        setContentView(binding.root)


        adView = AdView(this)
        delayedInit()
        postViewModel = ViewModelProvider(this)[PostViewModel::class.java]


        setSupportActionBar(binding.toolbar)


        drawerLayout = binding.drawerLayout

        drawerToggle = ActionBarDrawerToggle(
            this,
            drawerLayout,
            binding.toolbar,
            R.string.app_name,
            R.string.app_name
        ).apply {
            drawerLayout.addDrawerListener(this)
            this.syncState()
        }
        


        initBackStackChangeListener()

        val navHostFragment =
            supportFragmentManager.findFragmentById(R.id.nav_host_fragment) as NavHostFragment?

        if (navHostFragment != null) {
            navController = navHostFragment.navController
        }




        appBarConfiguration = AppBarConfiguration(
            setOf(
                R.id.nav_home, R.id.nav_accessory,
                R.id.nav_arcade, R.id.nav_fashion,
                R.id.nav_food, R.id.nav_heath,
                R.id.nav_lifestyle, R.id.nav_sports, R.id.nav_favorites, R.id.settingsFragment
            ), drawerLayout
        )



        setupActionBarWithNavController(this, navController, appBarConfiguration)
        setupWithNavController(binding.navView, navController)

        _navGraph = navController.navInflater.inflate(R.navigation.mobile_navigation)


        onBackPressedDispatcher.addCallback(this /* lifecycle owner */,
            object : OnBackPressedCallback(true) {
                override fun handleOnBackPressed() {
                    // Back is pressed... Finishing the activity

                    finish()
                }
            })
    }


    override fun onResume() {
        super.onResume()
        adView.resume()

        postViewModel.currentDestination.observe(this) { currentDestination ->

            Log.w(TAG, "currentDestination: at first run is $currentDestination")

            navGraph.setStartDestination(currentDestination)
            navController.graph = navGraph


        }

        navController.addOnDestinationChangedListener { _, destination, _ ->
            Log.d(TAG, "addOnDestinationChangedListener: " + destination.id)

            if (destination.id != R.id.settingsFragment
                && destination.id != R.id.aboutFragment
                && destination.id != R.id.privacyPolicyFragment
                && destination.id != R.id.termsAndConditionsFragment
            ) {
                postViewModel.saveCurrentDestination(destination.id)
            }

        }
    }

 

    override fun onSupportNavigateUp(): Boolean {
        return navController.navigateUp(appBarConfiguration) || super.onSupportNavigateUp()
    }

    override fun showHamburgerIcon() {
        supportActionBar?.setDisplayHomeAsUpEnabled(false)
        drawerToggle.setDrawerIndicatorEnabled(true)
    }

    override fun showBackIcon() {
        supportActionBar?.setDisplayHomeAsUpEnabled(true)
        binding.toolbar.setNavigationIcon(R.drawable.ic_arrow_back_24)
        drawerToggle.setDrawerIndicatorEnabled(false)
    }

    private fun initBackStackChangeListener() {
        supportFragmentManager.addOnBackStackChangedListener {
            val fragment =   supportFragmentManager.findFragmentById(R.id.nav_host_fragment)

            if (fragment is SettingsFragment) {
                binding.toolbar.setNavigationIcon(R.drawable.ic_arrow_back_24)
                drawerToggle.isDrawerIndicatorEnabled = false
                drawerLayout.setDrawerLockMode(DrawerLayout.LOCK_MODE_LOCKED_CLOSED)
                drawerToggle.setToolbarNavigationClickListener { onBackPressed() }
                supportActionBar?.setDisplayHomeAsUpEnabled(true)
            } else {
                supportActionBar?.setDisplayHomeAsUpEnabled(false)
                drawerLayout.setDrawerLockMode(DrawerLayout.LOCK_MODE_UNLOCKED)
                drawerToggle.isDrawerIndicatorEnabled = true
                drawerToggle.toolbarNavigationClickListener = null
                drawerToggle.syncState()
            }
        }
    }


}


interface HideShowIconInterface {
    fun showHamburgerIcon()
    fun showBackIcon()
}

SettingsFragment

@AndroidEntryPoint
class SettingsFragment : Fragment() {

    private var _binding: FragmentSettingsBinding? = null
    private val binding get() = _binding!!

    private val settingsViewModel: SettingsViewModel by viewModels()


    override fun onCreateView(
        inflater: LayoutInflater,
        container: ViewGroup?,
        savedInstanceState: Bundle?
    ): View {

        _binding = FragmentSettingsBinding.inflate(inflater, container, false)

        (requireActivity() as MainActivity).showBackIcon()

        return binding.root
    }

Answer 1

Try this

navController.addOnDestinationChangedListener { _, destination, _ ->
            Log.d(TAG, "addOnDestinationChangedListener: " + destination.id)

            if (destination.id == R.id.settingsFragment) {
                drawerLayout.setDrawerLockMode(DrawerLayout.LOCK_MODE_LOCKED_CLOSED)
                if (drawerLayout.isDrawerOpen(GravityCompat.START)) {
                    drawerLayout.closeDrawer(GravityCompat.START)

                }

               binding.toolbar.setNavigationOnClickListener { //do whatever you want here

                   navController.navigateUp()
               }


            } else {
                drawerLayout.setDrawerLockMode(DrawerLayout.LOCK_MODE_UNLOCKED)

                binding.toolbar.setNavigationOnClickListener{
                    drawerLayout.openDrawer(GravityCompat.START)
                }

            }


   override fun showBackIcon() {
        supportActionBar?.setDisplayHomeAsUpEnabled(true)
        supportActionBar?.setDisplayShowHomeEnabled(true)
        binding.toolbar.setNavigationIcon(R.drawable.ic_arrow_back_24)
    }

and remove showHamburgerIcon & ActionBarDrawerToggle codes