Develop Reference

How to use findNavController() on itemOnClickListener of an adapter?

Im having a problem on my navigation, first i have an A fragment which has a recycler view, when i use the navigation to move to another fragment (B fragment) and come back to my A fragment i cant seem to be able to click on the item contained in the recycler view, it raises me "View androidx.constraintlayout.widget.ConstraintLayout{1f8e1b2 V.E...... ........ 0,0-1080,1823} does not have a NavController set". If i dont move in beetween fragments (stay in A fragment) it works just fine.
The onItemClicked on my adapter calls a findNavController().
ps: Sry for my bad english as im not native, and this is my first post
This is my MainActivity:
`
class MainActivity : AppCompatActivity() {
private lateinit var binding: ActivityMainMenuBinding
private lateinit var bottomNav: BottomNavigationView
private lateinit var navController: NavController
val authViewModel: AuthViewModel by viewModels()
val TAG: String = "ReceitaListingFragment"
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
startUI()
}
private fun setNavController(){
val navHostFragment = supportFragmentManager.findFragmentById(R.id.nav_host) as NavHostFragment
navController = navHostFragment.navController
setupWithNavController(bottomNav,navController)
}
private fun startUI() {
binding = ActivityMainMenuBinding.inflate(layoutInflater)
setContentView(binding.root)
bottomNav = findViewById(R.id.bottomNavigationView)
setNavController()
bottomNav.setOnItemSelectedListener {
when (it.itemId){
R.id.recipes -> {
val connected_to_internet:Boolean = isOnline(this)
val fragment:Fragment = RecipeListingFragment()
fragment.arguments = Bundle().apply {
putBoolean("connectivity",connected_to_internet)
}
replaceFragment(RecipeListingFragment())
}
R.id.profile -> replaceFragment(ProfileFragment())
}
true
}
}
private fun replaceFragment(fragment : Fragment){
val fragmentManager = supportFragmentManager
val fragmentTransaction = fragmentManager.beginTransaction()
fragmentTransaction.replace(R.id.nav_host,fragment)
fragmentTransaction.commit()
}
}
`
this is my main_activity.xml:
`
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout 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"
tools:context=".MainActivity">
<androidx.fragment.app.FragmentContainerView
android:id="#+id/nav_host"
android:name="androidx.navigation.fragment.NavHostFragment"
android:layout_width="0dp"
android:layout_height="0dp"
app:defaultNavHost="true"
app:layout_constraintBottom_toTopOf="#+id/bottomNavigationView"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:navGraph="#navigation/app_navigation" />
<com.google.android.material.bottomnavigation.BottomNavigationView
android:id="#+id/bottomNavigationView"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="#E3E3E4"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:itemIconTint="#color/bordeux"
app:itemTextColor="#color/bordeux"
app:menu="#menu/bottom_nav_menu" />
</androidx.constraintlayout.widget.ConstraintLayout>
`
this is how i initialize my adapter in RecipeListingFragment:
`
private val adapter by lazy {
RecipeListingAdapter(
onItemClicked = {pos,item ->
findNavController().navigate(R.id.action_receitaListingFragment_to_receitaDetailFragment,Bundle().apply {
putParcelable("note",item)
})
},
this.authModel
)
}
`
this is how i set my adapter in RecipeListingFragment:
`
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
binding.recyclerView.adapter = adapter
}
`
this is my navigation.xml:
`
<navigation 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/app_navigation"
app:startDestination="#id/receitaListingFragment">
<fragment
android:id="#+id/receitaListingFragment"
android:name="com.example.projectfoodmanager.ui.recipe.RecipeListingFragment"
android:label="fragment_receita_listing"
tools:layout="#layout/fragment_recipe_listing" >
<action
android:id="#+id/action_receitaListingFragment_to_receitaDetailFragment"
app:destination="#id/receitaDetailFragment" />
<action
android:id="#+id/action_receitaListingFragment_to_profileFragment"
app:destination="#id/profileFragment" />
</fragment>
<fragment
android:id="#+id/receitaDetailFragment"
android:name="com.example.projectfoodmanager.ui.recipe.RecipeDetailFragment"
android:label="fragment_recipe_detail"
tools:layout="#layout/fragment_recipe_detail" >
<action
android:id="#+id/action_receitaDetailFragment_to_receitaListingFragment"
app:destination="#id/receitaListingFragment" />
</fragment>
<fragment
android:id="#+id/profileFragment"
android:name="com.example.projectfoodmanager.ui.profile.ProfileFragment"
android:label="fragment_profile"
tools:layout="#layout/fragment_profile" >
<action
android:id="#+id/action_profileFragment_to_receitaListingFragment"
app:destination="#id/receitaListingFragment" />
</fragment>
<fragment
android:id="#+id/calenderFragment"
android:name="com.example.projectfoodmanager.ui.views.CalenderFragment"
android:label="fragment_calender"
tools:layout="#layout/fragment_calender" >
</fragment>
<fragment
android:id="#+id/favoritesFragment"
android:name="com.example.projectfoodmanager.ui.views.FavoritesFragment"
android:label="fragment_favorites"
tools:layout="#layout/fragment_favorites" >
</fragment>
<fragment
android:id="#+id/goalFragment"
android:name="com.example.projectfoodmanager.ui.views.GoalFragment"
android:label="fragment_goal"
tools:layout="#layout/fragment_goal" >
</fragment>
</navigation>
`

Try to using RecyclerView and move fragment navigation to your Fragment.
Your Adapter:
class MyCustomAdapter(
val openFragment: () -> Unit
) :
RecyclerView.Adapter<PromoAdapter.UserViewHolder>() {
override fun onBindViewHolder(holder: UserViewHolder, position: Int) {
holder.button.setOnClickListener {
openFragment()
}
}
}
In Fragment:
val mAdapter = MyCustomAdapter(
openFragment = {
// Navigate to Fragment
}
)

How can I use Navigation (NavHost) in nested fragments?

I'm trying to open Fragment2 from Fragment1(TransformFragment)
throught click item in RecyclerView. I tried to use Navigation (NavHost) to solve this problem.
Fragment1 code as below:
class TransformFragment : Fragment() {
private lateinit var transformViewModel: TransformViewModel
private var _binding: FragmentTransformBinding? = null
// This property is only valid between onCreateView and
// onDestroyView.
private val binding
get() = _binding!!
override fun onCreateView(
inflater: LayoutInflater,
container: ViewGroup?,
savedInstanceState: Bundle?
): View {
transformViewModel = ViewModelProvider(this)[TransformViewModel::class.java]
_binding = FragmentTransformBinding.inflate(inflater, container, false)
val root: View = binding.root
val recyclerView = binding.recyclerviewTransform
val adapter = TransformAdapter()
recyclerView.adapter = adapter
transformViewModel.texts.observe(viewLifecycleOwner) { adapter.submitList(it) }
return root
}
override fun onDestroyView() {
super.onDestroyView()
_binding = null
}
class TransformAdapter() :
ListAdapter<String, TransformViewHolder>(
object : DiffUtil.ItemCallback<String>() {
override fun areItemsTheSame(oldItem: String, newItem: String): Boolean =
oldItem == newItem
override fun areContentsTheSame(oldItem: String, newItem: String): Boolean =
oldItem == newItem
}
) {
private val drawables =
listOf(
R.drawable.avatar_1,
R.drawable.avatar_2,
R.drawable.avatar_3,
R.drawable.avatar_4,
R.drawable.avatar_5,
R.drawable.avatar_6,
R.drawable.avatar_7,
R.drawable.avatar_8,
R.drawable.avatar_9,
R.drawable.avatar_10,
R.drawable.avatar_11,
R.drawable.avatar_12,
R.drawable.avatar_13,
R.drawable.avatar_14,
R.drawable.avatar_15,
R.drawable.avatar_16,
R.drawable.avatar_17,
)
override fun onCreateViewHolder(parent: ViewGroup, viewType: Int): TransformViewHolder {
val binding = ItemTransformBinding.inflate(LayoutInflater.from(parent.context))
return TransformViewHolder(binding)
}
override fun onBindViewHolder(holder: TransformViewHolder, position: Int) {
holder.textView.text = getItem(position)
holder.imageView.setImageDrawable(
ResourcesCompat.getDrawable(holder.imageView.resources, drawables[position], null)
)
holder.itemView.setOnClickListener {
// my navigation(NavHost) code
}
}
}
class TransformViewHolder(binding: ItemTransformBinding) :
RecyclerView.ViewHolder(binding.root) {
val imageView: ImageView = binding.imageViewItemTransform
val textView: TextView = binding.textViewItemTransform
}
}
I tried to use this:
val navController = findNavController(R.id.nav_host_fragment_content_main)
navController.navigate(R.id.nav_detail)
nav_detail to navigate Fragment2, and My Fragment Container. This's my XML. I know that to display Dynamiclly Fragments, you must use FrameLayout, but it produces errors and the fragment container is OK.
<LinearLayout 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:orientation="vertical"
app:layout_behavior="#string/appbar_scrolling_view_behavior"
tools:showIn="#layout/app_bar_main">
<fragment
android:id="#+id/nav_host_fragment_content_main"
android:name="androidx.navigation.fragment.NavHostFragment"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_marginLeft="#dimen/fragment_horizontal_margin"
android:layout_marginRight="#dimen/fragment_horizontal_margin"
android:layout_weight="1"
app:defaultNavHost="true"
app:navGraph="#navigation/mobile_navigation" />
<!--
<FrameLayout
android:id="#+id/nav_host_fragment_content_main"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_marginLeft="#dimen/fragment_horizontal_margin"
android:layout_marginRight="#dimen/fragment_horizontal_margin"
android:layout_weight="1"
app:defaultNavHost="true"
app:navGraph="#navigation/mobile_navigation" />
-->
</LinearLayout>

I've found the correct answer in Android developers documentation.
holder.itemView.setOnClickListener {
it.findNavController().navigate(R.id.nav_detail)
}

To use findNavController() to navigate between fragments, you've to make sure that you've setup with activity properly first.
So, in your activity layout first add container, parent need nod to be FrameLayout itself, I'm gonna make use of ConstraintLayout below.
activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
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"
tools:context=".MainActivity">
<!-- We declare attribute id to hook with MainActivity.java class-->
<!-- Attribute name will change behavior of simple fragment to NavHostFragment-->
<!-- Keep width and height to match_parent so that all our fragments take whole space-->
<!-- We change this NavHost to behave default NavHost-->
<!-- Attach our app navigation graph to this NavHostFragment-->
<fragment
android:id="#+id/nav_host_fragment"
android:name="androidx.navigation.fragment.NavHostFragment"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:defaultNavHost="true"
app:navGraph="#navigation/nav_graph" />
</androidx.constraintlayout.widget.ConstraintLayout>
Now let's hook container as an acting host for activity.
MainActivity.kt
class MainActivity : AppCompatActivity() {
lateinit var navController: NavController
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
// NavigationController to set default NavHost as nav_host_fragment.
navController = Navigation.findNavController(this, R.id.nav_host_fragment)
NavigationUI.setupActionBarWithNavController(this, navController)
}
override fun onSupportNavigateUp(): Boolean {
return navController.navigateUp()
}
}
onSupportNavigateUp function helps you to navigate back to previous fragment on action trigered or called specifically on any view with navigateUp().
Now you want to navigate from Fragment1 -> Fragment2.
Make sure you've added two fragments to navigation graph.
Connect first fragment to second with action.
Keep track of destination Id's to call correct one.
<?xml version="1.0" encoding="utf-8"?>
<navigation 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/nav_graph"
app:startDestination="#id/firstFragment">
<fragment
android:id="#+id/firstFragment"
android:name=".FirstFragment"
android:label="FirstFragment"
tools:layout="#layout/fragment_first">
<action
android:id="#+id/action_first_fragment_to_second_fragment"
app:destination="#id/secondFragment" />
</fragment>
<fragment
android:id="#+id/secondFragment"
android:name=".SecondFragment"
android:label="Authors"
tools:layout="#layout/fragment_second" />
</navigation>
Now finally once action is triggered call action with id like below on controller.
yourListItemView.setOnClickListener {
findNavController(R.id.action_first_fragment_to_second_fragment)
}
That's it.
Please check the documentation, it has a good information.

Android: How to open a Fragment with Navigation Graph without replacing the current Fragment

I am wondering if there is a way to add another fragment to the screen without replacing the old one with the Navigation Graph.
I want to do this because the new fragment will just be open for a bit just to check some details and when the user returns to the previous fragment, I want them to be in the same spot they left off.
I have read around but I couldn't find one that does it without replacing the original. I have tried to just add it to the nav_graph_fragment which I try to do this in the newFrag() function in the CurrentFragment section but it doesn't work.
Main Activty
class MainActivity : AppCompatActivity() {
private lateinit var toolbar: Toolbar
private val navController by lazy {
(supportFragmentManager.findFragmentById(R.id.nav_host_fragment) as NavHostFragment).navController
}
private lateinit var appBarConfiguration: AppBarConfiguration
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.main_activity)
toolbar = findViewById(R.id.mainToolBar)
setSupportActionBar(toolbar)
appBarConfiguration = AppBarConfiguration(navController.graph, null)
setupActionBarWithNavController(navController, appBarConfiguration)
}
override fun onCreateOptionsMenu(menu: Menu?): Boolean {
val inflater: MenuInflater = menuInflater
inflater.inflate(R.menu.main_menu_bar, menu)
return true
}
override fun onSupportNavigateUp(): Boolean {
return navController.navigateUp(appBarConfiguration) || super.onSupportNavigateUp()
}
override fun onOptionsItemSelected(item: MenuItem): Boolean {
val navController = findNavController(R.id.nav_host_fragment)
if (item.itemId == navController.currentDestination?.id)
return true
return item.onNavDestinationSelected(navController) || super.onOptionsItemSelected(item)
}
}
Main Activity xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="#+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".activity.MainActivity">
<include
layout="#layout/appbar"
android:id="#+id/mainToolBar"/>
<androidx.fragment.app.FragmentContainerView
android:id="#+id/nav_host_fragment"
android:name="androidx.navigation.fragment.NavHostFragment"
android:layout_width="0dp"
android:layout_height="0dp"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toBottomOf="#id/mainToolBar"
app:layout_constraintBottom_toBottomOf="parent"
app:defaultNavHost="true"
app:navGraph="#navigation/nav_graph" />
</androidx.constraintlayout.widget.ConstraintLayout>
CurrentFragment
class CurrentFragment : Fragment() {
private lateinit var currentFragmentViewModel: CurrentFragmentViewModel
private lateinit var binding: CurrentFragmentBinding
private lateinit var recyclerView: RecyclerView
override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View? {
binding = DataBindingUtil.inflate(inflater, R.layout.current_fragment, container, false)
currentFragmentViewModel = ViewModelProvider(this).get(CurrentFragmentViewModel::class.java)
binding.lifecycleOwner = this
binding.viewmodel = currentFragmentViewModel
binding.accountButton.setOnClickListener {
Log.d("TEST", "button clicked")
newFrag()
}
return binding.root
}
// Here is where I am trying to open the new fragment
private fun newFrag() {
val newFrag = Fragment()
val transaction: FragmentTransaction = parentFragmentManager.beginTransaction()
transaction.hide(this)
transaction.add(R.id.nav_host_fragment, newFrag).commit()
}
}
Nav Graph
<?xml version="1.0" encoding="utf-8"?>
<navigation 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/nav_graph"
app:startDestination="#id/mainFragment">
<fragment
android:id="#+id/mainFragment"
android:name="com.example.app.ui.main.MainFragment"
android:label="MainFragment">
<action
android:id="#+id/action_mainFragment_to_currentFragment"
app:destination="#id/currentFragment" />
</fragment>
<fragment
android:id="#+id/currentFragment"
android:name="com.example.app.ui.search.CurrentFragment"
android:label="currentFragment" >
</fragment>

Android: Navigation Component - How to connect Toolbar menu to the fragments?

Iv been stuck in trying to add the Navigation Component to my app. Specifically to my toolbar menu items.
I have been following the navigation migrate documentation on Android's site but I am getting a but confused on how it works or even to set it up.
This is a single-activity multi-fragment architecture.
The app would start in the MainFragment and then when tapping the menu items in the toolbar, such as Main Frag to Search Movie Frag. The user would be able to navigate using the menu items from anywhere in the app (e.g. if they click the home icon, they should be sent to the home screen form anywhere in the app. Still thinking if thats how it should be done).
The main thing is I don't know how to properly attach the Navigation Component to the menu items.
App
Nav Graph
nav_graph.xml
<?xml version="1.0" encoding="utf-8"?>
<navigation 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/nav_graph"
app:startDestination="#id/mainFragment">
<fragment
android:id="#+id/mainFragment"
android:name="com.example.movieapp.ui.main.MainFragment"
android:label="MainFragment">
<action
android:id="#+id/action_mainFragment_to_searchMovieFragment"
app:destination="#id/searchMovieFragment" />
</fragment>
<fragment
android:id="#+id/searchMovieFragment"
android:name="com.example.movieapp.ui.search.SearchMovieFragment"
android:label="SearchMovieFragment" />
</navigation>
main_activity.xml
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="#+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".activity.MainActivity">
<include
layout="#layout/appbar"
android:id="#+id/mainToolBar"/>
<androidx.fragment.app.FragmentContainerView
android:id="#+id/nav_host_fragment"
android:name="androidx.navigation.fragment.NavHostFragment"
android:layout_width="0dp"
android:layout_height="0dp"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"
app:layout_constraintTop_toBottomOf="#id/mainToolBar"
app:layout_constraintBottom_toBottomOf="parent"
app:defaultNavHost="true"
app:navGraph="#navigation/nav_graph" />
</androidx.constraintlayout.widget.ConstraintLayout>
MainActivity.kt
class MainActivity : AppCompatActivity() {
private lateinit var toolbar: Toolbar
private val navController by lazy {
(supportFragmentManager.findFragmentById(R.id.nav_host_fragment) as NavHostFragment).navController
}
private lateinit var appBarConfiguration: AppBarConfiguration
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.main_activity)
toolbar = findViewById(R.id.mainToolBar)
setSupportActionBar(toolbar)
appBarConfiguration = AppBarConfiguration(navController.graph, null)
setupActionBarWithNavController(navController, appBarConfiguration)
}
override fun onCreateOptionsMenu(menu: Menu?): Boolean {
val inflater: MenuInflater = menuInflater
inflater.inflate(R.menu.main_menu_bar, menu)
return true
}
override fun onSupportNavigateUp(): Boolean {
return navController.navigateUp(appBarConfiguration) || super.onSupportNavigateUp()
}
}
MainFragment.kt
class MainFragment : Fragment() {
companion object {
fun newInstance() = MainFragment()
}
private lateinit var viewModel: MainViewModel
private lateinit var binding: MainFragmentBinding
private lateinit var navController: NavController
override fun onCreateView(inflater: LayoutInflater, container: ViewGroup?, savedInstanceState: Bundle?): View {
binding = DataBindingUtil.inflate(inflater, R.layout.main_fragment, container, false)
setHasOptionsMenu(true)
return binding.root
}
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
navController = Navigation.findNavController(view)
// navController.navigate(R.id.action_mainFragment_to_searchMovieFragment)
}
override fun onActivityCreated(savedInstanceState: Bundle?) {
super.onActivityCreated(savedInstanceState)
viewModel = ViewModelProvider(this).get(MainViewModel::class.java)
binding.viewModel = viewModel
// TODO: Use the ViewModel
}
}
main_fragment.xml
<?xml version="1.0" encoding="utf-8"?>
<layout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools">
<data>
<variable
name="viewModel"
type="com.example.movieapp.ui.main.MainViewModel" />
</data>
<LinearLayout
android:orientation="vertical"
android:id="#+id/main_fragment"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".ui.main.MainFragment">
<TextView
android:id="#+id/message"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="MainFragment1" />
</LinearLayout>
</layout>

The id for a menu item in your file main_menu_bar.xml needs to match the id for the destination(fragment) specified in your navigation graph (nav_graph.xml).
Your main_menu_bar.xml should look something like this:
<menu xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
tools:showIn="navigation_view">
<group android:checkableBehavior="single">
<item
android:id="#id/searchMovieFragment"
android:icon="#drawable/search"
android:title="#string/menu_search" />
<item
android:id="#id/mainFragment"
android:icon="#drawable/ic_menu_camera"
android:title="#string/menu_home" />
</group>
</menu>
Also, you need to override the onOptionsItemSelected(MenuItem) method and associate your menu items with destinations. Like so:
override fun onOptionsItemSelected(item: MenuItem): Boolean {
val navController = findNavController(R.id.nav_host_fragment)
return item.onNavDestinationSelected(navController) || super.onOptionsItemSelected(item)
}
Reference

You can add a Toolbar on top of the most basic FragmentContainerView, access this toolbar from other fragments, and change the toolbar I created separately according to the fragment in it while opening the relevant fragment as follows.
toolbar = requireActivity().findViewById(R.id.toolbar_base)
toolbar?.menu?.clear()
toolbar?.title = ""
val toolbarFlowFragment = context?.let { getInflateLayout(it, R.layout.toolbar_profile) }
toolbar?.addView(toolbarFlowFragment)

Navigation Component - ActionBar handle in Activity only

I am finally adopting Navigation Architecture Components in a new project and I am already encountering some issues that the docs don't seem to address.
With an ActionBar menu setup in the activity, when I navigate to another fragment and then try to use the ActionBar menu I receive
java.lang.IllegalArgumentException: Navigation action/destination X cannot be found from the current destination
It would appear that I must also add actions from all possible destinations to goto all other destinations which seems like overkill, this just cannot be. There must be a solution to this problem that I am not finding.
I intend to open the app which inflates MainActivity and then MainFragment within the fragment element. The MainActivity should still handle top level navigation within the ActionBar. There is absolutely no reason I need to dupe menu click work in every fragment and define destinations to all other areas of the app.
MainActivity
class MainActivity : AppCompatActivity() {
private lateinit var navController: NavController
private lateinit var appBarConfiguration: AppBarConfiguration
private var menu: Menu? = null
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
val controller by lazy { findNavController(R.id.fragment_container) }
navController = controller
val appBarConfig by lazy { AppBarConfiguration(navController.graph) }
appBarConfiguration = appBarConfig
setSupportActionBar(toolbar)
setupActionBarWithNavController(navController, appBarConfiguration)
}
override fun onCreateOptionsMenu(menu: Menu?): Boolean {
menuInflater.inflate(R.menu.appbar_menu, menu)
this.menu = menu
return true
}
override fun onOptionsItemSelected(item: MenuItem): Boolean {
var direction: NavDirections? = null
when(item.itemId) {
R.id.action_messages -> {
direction = MainFragmentDirections.actionMainFragmentToMessagesFragment()
}
R.id.action_menu -> {
direction = MainFragmentDirections.actionMainFragmentToMessagesFragment()
}
else -> super.onOptionsItemSelected(item)
}
if (direction != null) navController.navigate(direction)
return true
}
override fun onSupportNavigateUp(): Boolean {
return navController.navigateUp(appBarConfiguration) || super.onSupportNavigateUp()
}
}
activity_main
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
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/card_id_test"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity">
<androidx.appcompat.widget.Toolbar
android:id="#+id/toolbar"
android:layout_width="match_parent"
android:layout_height="?actionBarSize"
android:background="#color/colorPrimary"
android:elevation="4dp"
android:clipToPadding="false"
app:menu="#menu/appbar_menu"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:titleTextColor="#color/white" />
<fragment
android:id="#+id/fragment_container"
android:name="androidx.navigation.fragment.NavHostFragment"
android:layout_width="match_parent"
android:layout_height="0dp"
app:defaultNavHost="true"
app:navGraph="#navigation/nav_graph"
app:layout_constraintTop_toBottomOf="#+id/toolbar"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintEnd_toEndOf="parent"/>
</androidx.constraintlayout.widget.ConstraintLayout>
MainFragment
class MainFragment : Fragment() {
private var _binding: FragmentMainBinding? = null
private val binding get() = _binding!!
private var mActivity : MainActivity? = null
private var mView: View? = null
override fun onCreateView(
inflater: LayoutInflater,
container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
super.onCreateView(inflater, container, savedInstanceState)
_binding = FragmentMainBinding.inflate(inflater, container, false)
mView = binding.root
mActivity = (activity as MainActivity)
return mView
}
override fun onViewCreated(view: View, savedInstanceState: Bundle?) {
super.onViewCreated(view, savedInstanceState)
btn_dashboard.setOnClickListener {
findNavController().navigate(
MainFragmentDirections.actionMainFragmentToDashboardFragment())
}
}
}
fragment_main
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="#+id/content_test"
android:layout_width="match_parent"
android:layout_height="match_parent">
<androidx.appcompat.widget.AppCompatTextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintBottom_toBottomOf="parent"
android:text="Main Fragment"
android:textSize="24dp" />
<com.google.android.material.button.MaterialButton
android:id="#+id/btn_dashboard"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="16dp"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintBottom_toBottomOf="parent"
android:text="Dashboard" />
</androidx.constraintlayout.widget.ConstraintLayout>
DashboardFragment
class DashboardFragment : Fragment() {
private var _binding: FragmentDashboardBinding? = null
private val binding get() = _binding!!
private var mActivity : MainActivity? = null
private var mView: View? = null
override fun onCreateView(
inflater: LayoutInflater,
container: ViewGroup?,
savedInstanceState: Bundle?
): View? {
super.onCreateView(inflater, container, savedInstanceState)
_binding = FragmentDashboardBinding.inflate(inflater, container, false)
mView = binding.root
mActivity = (activity as MainActivity)
return mView
}
}
fragment_dashboard
<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="#+id/content_test"
android:layout_width="match_parent"
android:layout_height="match_parent">
<androidx.appcompat.widget.AppCompatTextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintBottom_toBottomOf="parent"
android:text="Dashboard Fragment"
android:textSize="24dp" />
</androidx.constraintlayout.widget.ConstraintLayout>
nav_graph
<?xml version="1.0" encoding="utf-8"?>
<navigation
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="#+id/nav_graph"
app:startDestination="#id/mainFragment">
<fragment
android:id="#+id/mainFragment"
android:name="com.example.appbarnavigation.MainFragment"
android:label="Main" >
<action
android:id="#+id/action_mainFragment_to_messagesFragment"
app:destination="#id/action_messages" />
<action
android:id="#+id/action_mainFragment_to_menuFragment"
app:destination="#id/action_menu" />
<action
android:id="#+id/action_mainFragment_to_dashboardFragment"
app:destination="#id/dashboardFragment" />
</fragment>
<fragment
android:id="#+id/action_messages"
android:name="com.example.appbarnavigation.MessagesFragment"
android:label="Messages" />
<fragment
android:id="#+id/action_menu"
android:name="com.example.appbarnavigation.MenuFragment"
android:label="Menu" />
<fragment
android:id="#+id/dashboardFragment"
android:name="com.example.appbarnavigation.DashboardFragment"
android:label="Dashboard" />
</navigation>
appbar_menu
<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto">
<item
android:id="#+id/action_messages"
android:orderInCategory="1"
android:title="Messages"
android:icon="#drawable/ic_message"
app:showAsAction="always"/>
<item
android:id="#+id/action_menu"
android:orderInCategory="2"
android:title="Menu"
android:icon="#drawable/ic_menu"
app:showAsAction="always"/>
</menu>

This was resolved by defining and using global actions.
<?xml version="1.0" encoding="utf-8"?>
<navigation
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:id="#+id/nav_graph"
app:startDestination="#id/mainFragment">
<fragment
android:id="#+id/mainFragment"
android:name="com.example.appbarnavigation.MainFragment"
android:label="Main" >
<action
android:id="#+id/action_mainFragment_to_dashboardFragment"
app:destination="#id/dashboardFragment" />
</fragment>
<fragment
android:id="#+id/action_messages"
android:name="com.example.appbarnavigation.MessagesFragment"
android:label="Messages" />
<fragment
android:id="#+id/action_menu"
android:name="com.example.appbarnavigation.MenuFragment"
android:label="Menu" />
<fragment
android:id="#+id/dashboardFragment"
android:name="com.example.appbarnavigation.DashboardFragment"
android:label="Dashboard" />
<action android:id="#+id/action_global_action_messages" app:destination="#id/action_messages" />
<action android:id="#+id/action_global_action_menu" app:destination="#id/action_menu" />
</navigation>
and in the MainActivity
override fun onOptionsItemSelected(item: MenuItem) = when(item.itemId) {
R.id.action_messages -> {
navController.navigate(R.id.action_global_action_messages)
true
}
R.id.action_menu -> {
navController.navigate(R.id.action_global_action_menu)
true
}
// This is used for menu buttons or anything not explicitly defined here
else -> {
super.onOptionsItemSelected(item)
}
}