Tag: LOCK_MODE_UNLOCKED

An example of using a Navigation Listener would be to limit the screens on which your Navigation Drawer will be available. In this instance the drawer is locked on all screens other than the start destination (the opening Fragment):

import ...
class MainActivity : AppCompatActivity() {
    lateinit var drawerLayout: DrawerLayout
    lateinit var navController: NavController
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        @Suppress("UNUSED_VARIABLE")
        val binding = DataBindingUtil.setContentView<ActivityMainBinding>(this, R.layout.activity_main)
        navController = this.findNavController(R.id.myNavHostFragment)
        drawerLayout = binding.drawerLayout
        NavigationUI.setupActionBarWithNavController(this, navController, drawerLayout)

        // Add a listener which will determine if the destination is the start destination. If not, the nav drawer will be locked
        navController.addOnNavigatedListener { nc: NavController, nd: NavDestination -> // This currently doesn't work with Navigation version above 1.0.0-alpha07
            if (nd.id == nc.graph.startDestination) {
                drawerLayout.setDrawerLockMode(DrawerLayout.LOCK_MODE_UNLOCKED)
            } else {
                drawerLayout.setDrawerLockMode(DrawerLayout.LOCK_MODE_LOCKED_CLOSED)
            }
        }

        NavigationUI.setupWithNavController(binding.navView, navController)
    }

    override fun onSupportNavigateUp(): Boolean {
//        return navController.navigateUp()
        return NavigationUI.navigateUp(navController, drawerLayout)
    }
}