How does one remove the BACK arrow from the AppNavBar? - kotlin

Question

I've read a few lightly documented explanations of this on StackOverflow, but nothing that helps. What I've done is created a sample app with Navigation Drawer Activity using Android Studio that features the hamburger nav icon and a sliding nav drawer functionality. It works great!
However, when I copy every aspect of that sample app into my app, from the MainActivity, AppManifest, Navigation Map, to the theme settings to the layout XMLs, I still get a bloody back arrow and fragment title.
What code actually controls this?
This is what I need:
This is what I'm getting:
[]
My fear is that using DataBinding might be breaking some associations for the AppNavBar settings.
This is my main_activity.xml
<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools">
<androidx.drawerlayout.widget.DrawerLayout
android:id="#+id/drawer_layout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fitsSystemWindows="true"
tools:openDrawer="start">
<include
android:id="#+id/app_bar_main"
layout="#layout/app_bar_main"
android:layout_width="match_parent"
android:layout_height="match_parent" />
<com.google.android.material.navigation.NavigationView
android:id="#+id/nav_view"
android:layout_width="wrap_content"
android:layout_height="match_parent"
android:layout_gravity="start"
android:fitsSystemWindows="true"
app:headerLayout="#layout/nav_header_main"
app:menu="#menu/sc_drawer_menu_items" />
</androidx.drawerlayout.widget.DrawerLayout>
</layout>
This is my MainActivity class.
open class MainActivity : AppCompatActivity() {
private lateinit var appBarConfiguration: AppBarConfiguration
private lateinit var binding: MainActivityBinding
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
binding = DataBindingUtil.setContentView(this, R.layout.main_activity)
setSupportActionBar(binding.appBarMain.toolbar)
val drawerLayout: DrawerLayout = binding.drawerLayout
val navView: NavigationView = binding.navView
val navHostFragment = supportFragmentManager.findFragmentById(R.id.nav_host_fragment_content_main) as NavHostFragment
val navController = navHostFragment.navController
appBarConfiguration = AppBarConfiguration(
setOf(
R.id.sc_menu_i_inv_count,
R.id.sc_menu_i_work_orders,
R.id.sc_menu_i_ins_queue,
R.id.sc_menu_i_return_queue,
R.id.sc_menu_i_settings,
R.id.sc_menu_i_sign_out,
R.id.sc_menu_image_list_view
), drawerLayout
)
setupActionBarWithNavController(navController, appBarConfiguration)
navView.setupWithNavController(navController)
}
override fun onCreateOptionsMenu(menu: Menu): Boolean {
// Inflate the menu; this adds items to the action bar if it is present.
menuInflater.inflate(R.menu.main_activity, menu)
return true
}
override fun onSupportNavigateUp(): Boolean {
val navController = findNavController(R.id.nav_host_fragment_content_main)
return navController.navigateUp(appBarConfiguration) || super.onSupportNavigateUp()
}
}
Other than some changes for DataBindingUtils, it should perform the same as I understand it.

Answer 1

Found a solution. Added this code to my MainActivity.kt
val drawerLayout: DrawerLayout = binding.drawerLayout
val navView: NavigationView = binding.navView
val navHostFragment = supportFragmentManager.findFragmentById(R.id.nav_host_fragment_content_main) as NavHostFragment
val navController = navHostFragment.navController
getSupportActionBar()?.setDisplayHomeAsUpEnabled(true)
getSupportActionBar()?.setHomeButtonEnabled(true)
appBarConfiguration = AppBarConfiguration(
setOf(
R.id.sc_menu_i_inv_count,
R.id.sc_menu_i_work_orders,
R.id.sc_menu_i_ins_queue,
R.id.sc_menu_i_return_queue,
R.id.sc_menu_i_settings,
R.id.sc_menu_i_sign_out,
R.id.sc_menu_image_list_view
), drawerLayout
)
setupActionBarWithNavController(navController, appBarConfiguration)
navView.setupWithNavController(navController)
actionBarDrawerToggle =
ActionBarDrawerToggle(this,
drawerLayout,
binding.appBarMain.toolbar,
R.string.nav_open,
R.string.nav_close)
drawerLayout.addDrawerListener(actionBarDrawerToggle)
actionBarDrawerToggle.syncState()
supportActionBar!!.setDisplayHomeAsUpEnabled(true)