I’m new here.
Please help me solve the problem.
I want to switch between fragments in the future, now I have 2 of them.
I can’t create a fragment_container. It should be like this: supportFragmentManager.commit {
replace(fragment_container)
}

So the question is, how do I switch between fragments in my case?

I guess I need to move the markup from the main_activity file somewhere, but I don’t understand how.

<?xml version="1.0" encoding="utf-8"?>
<androidx.drawerlayout.widget.DrawerLayout
    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"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:id="@+id/drawer_layout"
    android:fitsSystemWindows="true"
    tools:openDrawer="start"
    tools:context=".MainActivity">




    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:orientation="vertical">
        <androidx.appcompat.widget.Toolbar
            android:layout_width="match_parent"
            android:layout_height="56dp"
            android:id="@+id/toolbar"
            android:elevation="4dp"
            android:background="#BF81C784"
            android:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
            android:popupTheme="@style/ThemeOverlay.AppCompat.Light"/>
        <FrameLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:id="@+id/fragment_containerz"/>
    </LinearLayout>
    <com.google.android.material.navigation.NavigationView
        android:layout_width="wrap_content"
        android:layout_height="match_parent"
        android:id="@+id/nav_view"
        android:layout_gravity="start"
        app:headerLayout="@layout/nav_header"
        app:menu="@menu/nav_menu"
        android:background="@color/white"
        app:itemIconTint="@color/lavender"
        app:itemTextColor="@color/black"/>





</androidx.drawerlayout.widget.DrawerLayout>

class MainActivity : AppCompatActivity(), NavigationView.OnNavigationItemSelectedListener {
    private lateinit var drawerLayout: DrawerLayout
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)



        //............. Левое всплывающее меня

        drawerLayout = findViewById<DrawerLayout>(R.id.drawer_layout)
        val toolbar = findViewById<Toolbar>(R.id.toolbar)
        setSupportActionBar(toolbar)
        val navigationView = findViewById<NavigationView>(R.id.nav_view)
        navigationView.setNavigationItemSelectedListener(this)
        val toggle = ActionBarDrawerToggle(
            this,
            drawerLayout,
            toolbar,
            R.string.open_nav,
            R.string.close_nav
        )
        drawerLayout.addDrawerListener(toggle)
        toggle.syncState()
        if (savedInstanceState == null) {
            supportFragmentManager.beginTransaction()
                .replace(R.id.fragment_containerz, HomeFragment()).commit()
            navigationView.setCheckedItem(R.id.nav_home)
        }
    }

    override fun onNavigationItemSelected(item: MenuItem): Boolean {
        when (item.itemId) {
            R.id.nav_home -> supportFragmentManager.beginTransaction()
                .replace(R.id.fragment_containerz, HomeFragment()).commit()

            R.id.nav_logout -> Toast.makeText(this, "Logout!", Toast.LENGTH_SHORT).show()
        }
        drawerLayout.closeDrawer(GravityCompat.START)
        return true
    }

    override fun onBackPressed() {
        if (drawerLayout.isDrawerOpen(GravityCompat.START)) {
            drawerLayout.closeDrawer(GravityCompat.START)
        } else {
            onBackPressedDispatcher.onBackPressed()
        }
    }

    //............. Левое всплывающее меня





}

Please help me solve the problem.
I want to switch between fragments in the future, now I have 2 of them.
I can’t create a fragment_container. It should be like this: supportFragmentManager.commit {
replace(fragment_container)
}

So the question is, how do I switch between fragments in my case?

I guess I need to move the markup from the main_activity file somewhere, but I don’t understand how.