How to enable navigation drawer only when we are in a certain fragment?

Question

I want to set my navigation drawer menu on a Fragment. I don't want the navigation drawer to show up when I start my app. I want it to show up after I enter another page (i.e. not first page). But the problem is, onSupportNavigateUp can only be written on MainActivity, which is the first page.

This is my MainActivity.kt :

class MainActivity : AppCompatActivity() {
    private lateinit var drawerLayout: DrawerLayout
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        @Suppress("UNUSED_VARIABLE")

        val binding = DataBindingUtil.setContentView<ActivityMainBinding>(this, R.layout.activity_main)
        drawerLayout = binding.drawerLayout

        val navController = this.findNavController(R.id.myNavHostFragment)
        NavigationUI.setupActionBarWithNavController(this,navController, drawerLayout)
        NavigationUI.setupWithNavController(binding.navView, navController)
    }

    override fun onSupportNavigateUp(): Boolean {
        val navController = this.findNavController(R.id.myNavHostFragment)
        return NavigationUI.navigateUp(navController, drawerLayout)
    }
}

Here is my activity_main.xml `

<androidx.drawerlayout.widget.DrawerLayout
    android:id="@+id/drawerLayout"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">

        <fragment
            android:id="@+id/myNavHostFragment"
            android:name="androidx.navigation.fragment.NavHostFragment"
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            app:navGraph="@navigation/navigation"
            app:defaultNavHost="true"
            />
    </LinearLayout>
    <com.google.android.material.navigation.NavigationView
        android:id="@+id/navView"
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:layout_gravity="start"
        app:headerLayout="@layout/nav_header"
        app:menu="@menu/navdrawer_menu" />
</androidx.drawerlayout.widget.DrawerLayout>

`

It takes fragment_title.xml display and use it for activity_main.xml display by using fragment tag and NavHostFragment.

I also have another fragment called fragment_home.xml and HomeFragment.kt class.

What I don't know is, how to not show the navigation drawer when I'm on title fragment and start showing the navigation drawer when I'm on home fragment?

Answer 1

Below code will set navView visibility gone in TitleFragment and set visible on the other destinations:

        navController.addOnDestinationChangedListener { _, destination, _ ->
            if (destination.id == R.id.titleFragment) {
                navView.visibility = View.GONE
            } else {
                navView.visibility = View.VISIBLE
            }
        }