How do I fix MainActivity does not have a navcontroller?

Question

I just got my code to compile and when I try to start the app I receive the error. I'm currently trying to setup RecycleView for my class project. My goal is to make the RecycleView show content sorta like the reddit mobile app. I thought my RecycleView named "scrollview1" had a navcontroller setup. Not sure why I'm getting this output

java.lang.RuntimeException: Unable to start activity ComponentInfo{com.john.chanapi/com.john.chanapi.MainActivity}: java.lang.IllegalStateException: Activity com.john.chanapi.MainActivity@1850938 does not have a NavController set on 2131230866 

My MainActivity.kt:

package com.john.chanapi  import android.os.Bundle import com.google.android.material.floatingactionbutton.FloatingActionButton import com.google.android.material.snackbar.Snackbar import androidx.navigation.findNavController import androidx.navigation.ui.AppBarConfiguration import androidx.navigation.ui.navigateUp import androidx.navigation.ui.setupActionBarWithNavController import androidx.navigation.ui.setupWithNavController import androidx.drawerlayout.widget.DrawerLayout import com.google.android.material.navigation.NavigationView import androidx.appcompat.app.AppCompatActivity import androidx.appcompat.widget.Toolbar import android.view.Menu import android.view.View  class MainActivity : AppCompatActivity() {      private lateinit var appBarConfiguration: AppBarConfiguration      override fun onCreate(savedInstanceState: Bundle?) {         super.onCreate(savedInstanceState)         setContentView(R.layout.activity_main)         val toolbar: Toolbar = findViewById(R.id.toolbar)         setSupportActionBar(toolbar)          val fab: FloatingActionButton = findViewById(R.id.fab)         fab.setOnClickListener { view ->             Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)                 .setAction("Action", null).show()         }         val drawerLayout: DrawerLayout = findViewById(R.id.drawer_layout)         val navView: NavigationView = findViewById(R.id.nav_view)         val navController = findNavController(R.id.scrollview1)         // Passing each menu ID as a set of Ids because each         // menu should be considered as top level destinations.         appBarConfiguration = AppBarConfiguration(             setOf(                 R.id.nav_home, R.id.nav_new, R.id.nav_rising,                 R.id.nav_top, R.id.nav_inbox, R.id.nav_message             ), 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, menu)         return true     }      override fun onSupportNavigateUp(): Boolean {         val navController = findNavController(R.id.scrollview1)         return navController.navigateUp(appBarConfiguration) || super.onSupportNavigateUp()     } } 

My activity_main.xml:

<?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:id="@+id/drawer_layout"     android:layout_width="match_parent"     android:layout_height="match_parent"     android:fitsSystemWindows="true"     tools:openDrawer="start">      <include         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/activity_main_drawer" />  </androidx.drawerlayout.widget.DrawerLayout> 

Answer 1

To be on the safer side, (within an Activity) avoid using findNavController(Int) to initialize a NavController instead initialize it from NavHostFragment as shown

val navHostFragment =             supportFragmentManager.findFragmentById(R.id.navigation_host) as NavHostFragment val navController: NavController = navHostFragment.navController 

Answer 2

use simple <fragment> tag instead of <com.google.android.material.navigation.NavigationView>