I am using The new **[Navigation Architecture Component][1]** in android and I am stuck in clearing the navigation stack after moving to a new fragment. 

Example: 
I am in the loginFragment and I want this fragment to be cleared from the stack when I navigate to the home fragment so that the user will not be returned back to the loginFragment when he presses the back button.

I am using a simple [NavHostFragment.findNavController(Fragment).navigate(R.id.homeFragment)][2] to navigate.

Current Code : 

    mAuth.signInWithCredential(credential)
                .addOnCompleteListener(getActivity(), new OnCompleteListener&lt;AuthResult&gt;() {
                    @Override
                    public void onComplete(@NonNull Task&lt;AuthResult&gt; task) {
                        if (task.isSuccessful()) {
                            NavHostFragment.findNavController(LoginFragment.this).navigate(R.id.homeFragment);
                        } else {
                            Log.w(TAG, &quot;signInWithCredential:failure&quot;, task.getException());
                        }
                    }
                });


I tried using the [NavOptions][3] in the [navigate()][4], but the back button is still sending me back to the loginFragment
                        

    NavOptions.Builder navBuilder = new NavOptions.Builder();
    NavOptions navOptions = navBuilder.setPopUpTo(R.id.homeFragment, false).build();   
                 NavHostFragment.findNavController(LoginFragment.this).navigate(R.id.homeFragment, null, navOptions);


  [1]: https://developer.android.com/topic/libraries/architecture/navigation/navigation-implementing
  [2]: https://developer.android.com/reference/androidx/navigation/fragment/NavHostFragment#findNavController(android.support.v4.app.Fragment)
  [3]: https://developer.android.com/reference/androidx/navigation/NavOptions.Builder
  [4]: https://developer.android.com/reference/androidx/navigation/NavController#navigate_7

How to clear navigation Stack after navigating to another fragment in Android

I am having an issue with the new Android Navigation Architecture component when I try to navigate from **one Fragment to another**, I get this weird error: 

    java.lang.IllegalArgumentException: navigation destination XXX
    is unknown to this NavController

Every other navigation works fine except this particular one.

I use `findNavController()` function of Fragment to get access to the `NavController`.

Any help will be appreciated.

IllegalArgumentException: navigation destination xxx is unknown to this NavController

I&#39;m using Android Navigation Component for Navigation. I have a LoginFragment which has a button to transition to SignUpFragment. On clicking the button I&#39;m getting this error.
   

    java.lang.IllegalStateException: View android.support.v7.widget.AppCompatButton{49d9bd1 VFED..C.. ...P.... 201,917-782,1061 #7f090172 app:id/signUpLink} does not have a NavController set

Here is my nav_graph.xml

    &lt;navigation xmlns:app=&quot;http://schemas.android.com/apk/res-auto&quot;
            xmlns:android=&quot;http://schemas.android.com/apk/res/android&quot;
            xmlns:tools=&quot;http://schemas.android.com/tools&quot;
            app:startDestination=&quot;@id/loginFragment&quot;&gt;
            &lt;fragment
                android:id=&quot;@+id/loginFragment&quot;
                android:name=&quot;org.fossasia.openevent.app.core.auth.login.LoginFragment&quot;
                android:label=&quot;login_fragment&quot;
                tools:layout=&quot;@layout/login_fragment&quot;&gt;
                &lt;action
                    android:id=&quot;@+id/action_loginFragment_to_signUpFragment&quot;
                    app:destination=&quot;@id/signUpFragment&quot; /&gt;
              
            &lt;/fragment&gt;
        &lt;/navigation&gt;

Here is the code in LoginFragment for Navigation -

    binding.signUpLink.setOnClickListener(Navigation.createNavigateOnClickListener(R.id.action_loginFragment_to_signUpFragment, null));

Here is extract from activity layout file for NavHostFragment -

    &lt;FrameLayout
        android:id=&quot;@+id/fragment_container&quot;
        android:layout_width=&quot;match_parent&quot;
        android:layout_height=&quot;match_parent&quot;
        app:layout_behavior=&quot;@string/appbar_scrolling_view_behavior&quot;
        android:name=&quot;android.navigation.fragment.NavHostFragment&quot;
        app:navGraph=&quot;@navigation/main_navigation&quot;
        app:defaultNavHost=&quot;true&quot;/&gt;



IllegalStateException: Link does not have a NavController set

I recently downloaded [Android Studio Bumblebee][1] and it helpfully asked whether I wanted to upgrade to Android Gradle Plugin 7.1.0, the version that shipped alongside Android Studio Bumblebee.

After upgrading, I get a build error:

```
Unable to load class &#39;com.android.build.api.extension.AndroidComponentsExtension&#39;.

This is an unexpected error. Please file a bug containing the idea.log file.
```

And looking at the `idea.log` file, I see:

```
A problem occurred evaluating project &#39;:main&#39;.
	at org.gradle.initialization.exception.DefaultExceptionAnalyser.transform(DefaultExceptionAnalyser.java:103)
	...
Caused by: org.gradle.api.GradleScriptException: A problem occurred evaluating project &#39;:main&#39;.
	at org.gradle.groovy.scripts.internal.DefaultScriptRunnerFactory$ScriptRunnerImpl.run(DefaultScriptRunnerFactory.java:93)
	...
Caused by: java.lang.NoClassDefFoundError: com/android/build/api/extension/AndroidComponentsExtension
	at androidx.navigation.safeargs.gradle.SafeArgsPlugin.apply(SafeArgsPlugin.kt:73)
	at androidx.navigation.safeargs.gradle.SafeArgsPlugin.apply(SafeArgsPlugin.kt:42)
	...
Caused by: java.lang.ClassNotFoundException: com.android.build.api.extension.AndroidComponentsExtension
```

Which means I can&#39;t run my app and I need to downgrade the AGP 7.0 to get things working again. How do I fix this and upgrade to Android Gradle Plugin 7.1.0?

  [1]: https://developer.android.com/studio/releases#bumblebee

Unable to load class AndroidComponentsExtension after upgrading the Android Gradle Plugin 7.1

I&#39;m trying to implement [Navigation with Jetpack&#39;s architecture components][1] in my existing app.

I have a single activity app where the main fragment (`ListFragment`) is a list of items. Currently, when the user taps on a list item a second fragment is added to the stack by `fragmentTransaction.add(R.id.main, detailFragment)`. So when back is pressed the `DetailFragment` is detached and the `ListFragment` is shown again.

With Navigation architecture this is handled automatically. Instead of adding the new fragment it&#39;s [replaced][2], so the fragment view is destroyed, `onDestroyView()` is called and `onCreateView()` is called when back is pressed to recreate the view.

I understand that this is a good pattern used with [LiveData][3] and [ViewModel][4] to avoid using more memory than necessary, but in my case this is annoying because the list has a complex layout and inflating it is time and CPU consuming, also because I&#39;ll need to save the scroll position of the list and scroll again to the same position user left the fragment. It&#39;s possible but seems it should exists a better way.

I&#39;ve tried to &quot;save&quot; the view in a private field on fragment and re-use it on `onCreateView()` if is already there, but it seems an anti-pattern.

    private View view = null;

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {

        if (view == null) {
            view = inflater.inflate(R.layout.fragment_list, container, false);
            //...
        }

        return view;
    }

Is there any other, more elegant, way to avoid re-inflating the layout?
  [1]: https://developer.android.com/topic/libraries/architecture/navigation/navigation-implementing
  [2]: https://issuetracker.google.com/issues/109856764
  [3]: https://developer.android.com/topic/libraries/architecture/livedata
  [4]: https://developer.android.com/reference/android/arch/lifecycle/ViewModel

Fragments destroyed / recreated with Jetpack&#39;s Android Navigation components

Let&#39;s say that we have two fragments: `MainFragment` and `SelectionFragment`. The second one is build for selecting some object, e.g. an integer. There are different approaches in receiving result from this second fragment like callbacks, buses etc. 

Now, if we decide to use Navigation Architecture Component in order to navigate to second fragment we can use this code:

    NavHostFragment.findNavController(this).navigate(R.id.action_selection, bundle)

where `bundle` is an instance of `Bundle` (of course). As you can see there is no access to `SelectionFragment` where we could put a callback. The question is, how to receive a result with Navigation Architecture Component?

How to get a result from fragment using Navigation Architecture Component?

I am using [Navigation][1] from [Android Jetpack][2] to navigate between  screens.
Now I want to set startDestination dynamically. 

I have an Activity named MainActivity
And two Fragments, FragmentA &amp; FragmentB.

    var isAllSetUp : Boolean = // It is dynamic and I’m getting this from Preferences.
    
        If(isAllSetUp)
        {
         // show FragmentA
        }
        else
        {
         //show FragmentB
        }

I want to set above flow using Navigation Architecture Component. Currently I have used startDestionation as below but it’s not fulfilling my requirement.

    &lt;navigation xmlns:android=&quot;http://schemas.android.com/apk/res/android&quot;
       xmlns:app=&quot;http://schemas.android.com/apk/res-auto&quot;
       xmlns:tools=&quot;http://schemas.android.com/tools&quot;
       android:id=&quot;@+id/lrf_navigation&quot;
       app:startDestination=&quot;@id/fragmentA&quot;&gt;
    
       &lt;fragment
           android:id=&quot;@+id/fragmentA&quot;
           android:name=&quot;com.mindinventory.FragmentA&quot;
           android:label=&quot;fragment_a&quot;
           tools:layout=&quot;@layout/fragment_a&quot; /&gt;
    &lt;/navigation&gt;



Is it possible to set startDestination conditionally using Android Navigation Architecture Component?


  [1]: https://developer.android.com/topic/libraries/architecture/navigation/navigation-implementing
  [2]: https://developer.android.com/jetpack/

Is it possible to set startDestination conditionally using Android Navigation Architecture Component(Android Jetpack)?

I have an activity A that start activity B passing to it some intent data. Activity B host a navigation graph from the new Navigation Architecture Component.I want to pass that intent data to the startDestination fragment as argument how to do that?

Navigation Architecture Component- Passing argument data to the startDestination

Android Jetpack Navigation, BottomNavigationView with auto fragment back stack on back button click?

What I wanted, after choosing multiple tabs one after another by user and user click on back button app must redirect to the last page he/she opened.

I achieved the same using Android ViewPager, by saving the currently selected item in an ArrayList. Is there any auto back stack after Android Jetpack Navigation Release? I want to achieve it using navigation graph

**activity_main.xml**

    &lt;?xml version=&quot;1.0&quot; encoding=&quot;utf-8&quot;?&gt;
    &lt;android.support.constraint.ConstraintLayout xmlns:android=&quot;http://schemas.android.com/apk/res/android&quot;
        xmlns:app=&quot;http://schemas.android.com/apk/res-auto&quot;
        xmlns:tools=&quot;http://schemas.android.com/tools&quot;
        android:id=&quot;@+id/container&quot;
        android:layout_width=&quot;match_parent&quot;
        android:layout_height=&quot;match_parent&quot;
        tools:context=&quot;.main.MainActivity&quot;&gt;
    
        &lt;fragment
            android:id=&quot;@+id/my_nav_host_fragment&quot;
            android:name=&quot;androidx.navigation.fragment.NavHostFragment&quot;
            android:layout_width=&quot;match_parent&quot;
            android:layout_height=&quot;0dp&quot;
            app:defaultNavHost=&quot;true&quot;
            app:layout_constraintBottom_toTopOf=&quot;@+id/navigation&quot;
            app:layout_constraintEnd_toEndOf=&quot;parent&quot;
            app:layout_constraintStart_toStartOf=&quot;parent&quot;
            app:layout_constraintTop_toTopOf=&quot;parent&quot;
            app:navGraph=&quot;@navigation/nav_graph&quot; /&gt;
    
        &lt;android.support.design.widget.BottomNavigationView
            android:id=&quot;@+id/navigation&quot;
            android:layout_width=&quot;0dp&quot;
            android:layout_height=&quot;wrap_content&quot;
            android:layout_marginStart=&quot;0dp&quot;
            android:layout_marginEnd=&quot;0dp&quot;
            android:background=&quot;?android:attr/windowBackground&quot;
            app:layout_constraintBottom_toBottomOf=&quot;parent&quot;
            app:layout_constraintLeft_toLeftOf=&quot;parent&quot;
            app:layout_constraintRight_toRightOf=&quot;parent&quot;
            app:menu=&quot;@menu/navigation&quot; /&gt;
    
    &lt;/android.support.constraint.ConstraintLayout&gt;


**navigation.xml**

    &lt;?xml version=&quot;1.0&quot; encoding=&quot;utf-8&quot;?&gt;
    &lt;menu xmlns:android=&quot;http://schemas.android.com/apk/res/android&quot;&gt;
    
        &lt;item
            android:id=&quot;@+id/navigation_home&quot;
            android:icon=&quot;@drawable/ic_home&quot;
            android:title=&quot;@string/title_home&quot; /&gt;
    
        &lt;item
            android:id=&quot;@+id/navigation_people&quot;
            android:icon=&quot;@drawable/ic_group&quot;
            android:title=&quot;@string/title_people&quot; /&gt;
    
        &lt;item
            android:id=&quot;@+id/navigation_organization&quot;
            android:icon=&quot;@drawable/ic_organization&quot;
            android:title=&quot;@string/title_organization&quot; /&gt;
    
        &lt;item
            android:id=&quot;@+id/navigation_business&quot;
            android:icon=&quot;@drawable/ic_business&quot;
            android:title=&quot;@string/title_business&quot; /&gt;
    
        &lt;item
            android:id=&quot;@+id/navigation_tasks&quot;
            android:icon=&quot;@drawable/ic_dashboard&quot;
            android:title=&quot;@string/title_tasks&quot; /&gt;
    
    &lt;/menu&gt;


also added 

    bottomNavigation.setupWithNavController(Navigation.findNavController(this, R.id.my_nav_host_fragment))


I got one answer from `Levi Moreira`, as follows

    navigation.setOnNavigationItemSelectedListener {item -&gt;
    
                onNavDestinationSelected(item, Navigation.findNavController(this, R.id.my_nav_host_fragment))
    
            }


But by doing this only happening is that last opened fragment&#39;s instance creating again.


Providing proper Back Navigation for BottomNavigationView



Android Jetpack Navigation, BottomNavigationView with Youtube or Instagram like proper back navigation (fragment back stack)?

I am using the new [Navigation](https://developer.android.com/topic/libraries/architecture/navigation/) component from Android Jetpack.

The root Activity setup is quite simple:

&lt;!-- language: kotlin --&gt;

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)
        setSupportActionBar(toolbar)
        
        val navController = findNavController(R.id.navigationFragment)
        setupActionBarWithNavController(navController)
    
        bottomNavigationView.setupWithNavController(navController)
    }

It works well when the Fragment&#39;s title is defined in the navigation graph. But for one Fragment, I want to set the title dynamically.

I tried with `findNavController().currentDestination.label = &quot;Hello world&quot;` but it does nothing.

I could of course use a trick like `(activity as? AppCompatActivity)?.supportActionBar?.title = &quot;Hello world&quot;`, but I feel that it will break the magic that `setupActionBarWithNavController()` does for me. It there any way to update the Action Bar title dynamically? 

Dynamic ActionBar title from a Fragment using AndroidX Navigation

Basically, I have the following navigation graph:

[![enter image description here][1]][1]


I want to change my starting point in navigation graph to `fragment 2` right after reaching it (in order to prevent going back to `fragment 1` when pressing back button - like with the splash screen).

This is my code:

    navGraph = navController.getGraph();
    navGraph.setStartDestination(R.id.fragment2);
    navController.setGraph(navGraph);

But, obviously it&#39;s not working and it gets back to `fragment 1` after pressing back button.

Am I doing it wrong?
Is there any other solution?


  [1]: https://i.stack.imgur.com/Y3yo0.jpg

How to change start destination of a navigation graph programmatically?

I have an activity with a product list fragment and many other fragments and I am trying to use architecture component navigation controller.

The problem is: it replaces the (start destination) product list fragment and I don&#39;t want the list to be reloaded when user click back button.

How to make the fragment transaction as add not replace?



Add (not replace) fragment with navigation architecture component

Is it possible to use the new Navigation Architecture Component with DialogFragment? Do I have to create a custom Navigator?

I would love to use them with the new features in my navigation graph.

Navigation Architecture Component - Dialog Fragments

When I try to add Safe Args (Android Navigation) to my app&#39;s as following

 ( using this guide : https://developer.android.com/topic/libraries/architecture/navigation/navigation-pass-data ) :

    apply plugin: &#39;com.android.application&#39;
    apply plugin: &#39;androidx.navigation.safeargs&#39;
    
    apply plugin: &#39;kotlin-android&#39;
    
    apply plugin: &#39;kotlin-android-extensions&#39;
    apply plugin: &#39;com.google.gms.google-services&#39;
    
    android {...

I receive this error :



&gt; **Plugin with id &#39;androidx.navigation.safeargs&#39; not found.**




Plugin with id &#39;androidx.navigation.safeargs&#39; not found

I am interested to try the Navigation graph showed in the Android Studio. But I got the preview unavailable after I import the [google sample][1]

I used the Android Studio 3.2 Preview Canary 16

[![enter image description here][2]][2]

    &lt;navigation xmlns:android=&quot;http://schemas.android.com/apk/res/android&quot;
        xmlns:app=&quot;http://schemas.android.com/apk/res-auto&quot;
        app:startDestination=&quot;@+id/launcher_home&quot;&gt;
    
        &lt;fragment
            android:id=&quot;@+id/launcher_home&quot;
            android:name=&quot;com.android.samples.arch.componentsbasicsample.StartFragment&quot;
            android:label=&quot;Home&quot;&gt;
    
            &lt;action
                android:id=&quot;@+id/end_action&quot;
                app:destination=&quot;@id/end_dest&quot; /&gt;
    
        &lt;/fragment&gt;
    
        &lt;fragment
            android:id=&quot;@+id/end_dest&quot;
            android:name=&quot;com.android.samples.arch.componentsbasicsample.EndFragment&quot;
            android:label=&quot;End&quot;
            &gt;
    
        &lt;/fragment&gt;
    &lt;/navigation&gt;

**Update on 10/6/2018:**

Even I rebuild the project it doesn&#39;t work. But if added new screen, it showed the new one in preview mode

[![enter image description here][3]][3]


  [1]: https://developer.android.com/jetpack/docs/ComponentsBasicSample.zip
  [2]: https://i.stack.imgur.com/stHfy.png
  [3]: https://i.stack.imgur.com/375I7.png

Navigation Preview unavailable in Android Studio 3.2 Preview

I have a workflow with 3 screens. From &quot;screen 1&quot; to access to &quot;screen 2&quot;, the user must accept some kind of *terms and conditions* that I call in my picture &quot;modal&quot;. But he only has to accept those conditions once. The next time he is on the first screen, he can go directly to screen 2. The user can chose to NOT accept the terms, and therefore we go back to &quot;screen 1&quot; and do not try to go to &quot;screen 2&quot;.

[![App workflow][1]][1]

I am wondering how to do it with the new [navigation component][2]. 

Previously, what I would do it:

* On screen 1, check if the user must accept the conditions
* If no, start &quot;screen 2&quot; activity
* If yes, use `startActivityForResult()` and wait result from the modal. Mark the terms as accepted. Start &quot;screen 2&quot;

But with the navigation graph, there is no way to start a Fragment to obtain a result.



I could mark the terms as accepted in the &quot;modal&quot; screen and start the &quot;screen 2&quot; from there. The thing is that to access to the screen 2, I need to do a network request. I do not want to duplicate the call to the API and processing its outcome in both &quot;screen 1&quot; and &quot;modal&quot;. 

**Is there a way to go back from &quot;modal&quot; to &quot;screen 1&quot; with some information (user accepted the terms), using Jetpack navigation?** 

*Edit:* I currently get around it by using the same flow that Yahya suggests below: using an Activity just for the modal and using `startActivityForResult` from the &quot;screen 1&quot;. I am just wondering if I could continue to use the navigation graph for the whole flow.

  [1]: https://i.stack.imgur.com/zWqMx.png
  [2]: https://developer.android.com/topic/libraries/architecture/navigation/

Equivalent of startActivityForResult() with Android Architecture Navigation

I was trying out Navigation architecture component and is now having difficulties in setting the title. How do I set the title programmatically and also how it works?

To clear my question, let&#39;s have an example, where, I&#39;ve set up a simple app with `MainActivity` hosting the navigation host controller, the `MainFragment` has a button and on clicking the button it goes to `DetailFragment`.

The same code from another question of [multiple app bars][1] on stack-overflow.

**MainActivity**

    public class MainActivity extends AppCompatActivity {
    
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
            Toolbar toolbar = findViewById(R.id.toolbar);
            setSupportActionBar(toolbar);

            // Setting up a back button
            NavController navController = Navigation.findNavController(this, R.id.nav_host);
            NavigationUI.setupActionBarWithNavController(this, navController);
        }
    
        @Override
        public boolean onSupportNavigateUp() {
            return Navigation.findNavController(this, R.id.nav_host).navigateUp();
        }
    }

**MainFragment**

    public class MainFragment extends Fragment {
    
        public MainFragment() {
            // Required empty public constructor
        }
    
        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                                 Bundle savedInstanceState) {
            // Inflate the layout for this fragment
            return inflater.inflate(R.layout.fragment_main, container, false);
        }
    
        @Override
        public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
            super.onViewCreated(view, savedInstanceState);
            Button buttonOne = view.findViewById(R.id.button_one);
            buttonOne.setOnClickListener(Navigation.createNavigateOnClickListener(R.id.detailFragment));
        }
    
    }

**DetailFragment**

    public class DetailFragment extends Fragment {
    
        public DetailFragment() {
            // Required empty public constructor
        }
    
        @Override
        public void onCreate(@Nullable Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
        }
    
        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container,
                                 Bundle savedInstanceState) {
            // Inflate the layout for this fragment
            return inflater.inflate(R.layout.fragment_detail, container, false);
        }
    }

**activity_main.xml**

    &lt;?xml version=&quot;1.0&quot; encoding=&quot;utf-8&quot;?&gt;
    &lt;androidx.coordinatorlayout.widget.CoordinatorLayout xmlns:android=&quot;http://schemas.android.com/apk/res/android&quot;
        xmlns:app=&quot;http://schemas.android.com/apk/res-auto&quot;
        xmlns:tools=&quot;http://schemas.android.com/tools&quot;
        android:layout_width=&quot;match_parent&quot;
        android:layout_height=&quot;match_parent&quot;
        android:animateLayoutChanges=&quot;true&quot;
        tools:context=&quot;.MainActivity&quot;&gt;
    
        &lt;com.google.android.material.appbar.AppBarLayout
            android:layout_width=&quot;match_parent&quot;
            android:layout_height=&quot;wrap_content&quot;
            android:animateLayoutChanges=&quot;true&quot;
            android:theme=&quot;@style/AppTheme.AppBarOverlay&quot;&gt;
    
            &lt;androidx.appcompat.widget.Toolbar
                android:id=&quot;@+id/toolbar&quot;
                android:layout_width=&quot;match_parent&quot;
                android:layout_height=&quot;?attr/actionBarSize&quot;
                android:background=&quot;?attr/colorPrimary&quot;
                app:popupTheme=&quot;@style/AppTheme.PopupOverlay&quot; /&gt;
    
        &lt;/com.google.android.material.appbar.AppBarLayout&gt;
    
        &lt;fragment
            android:id=&quot;@+id/nav_host&quot;
            android:name=&quot;androidx.navigation.fragment.NavHostFragment&quot;
            android:layout_width=&quot;match_parent&quot;
            android:layout_height=&quot;match_parent&quot;
            android:layout_gravity=&quot;top&quot;
            android:layout_marginTop=&quot;?android:attr/actionBarSize&quot;
            app:defaultNavHost=&quot;true&quot;
            app:layout_anchor=&quot;@id/bottom_appbar&quot;
            app:layout_anchorGravity=&quot;top&quot;
            app:layout_behavior=&quot;@string/appbar_scrolling_view_behavior&quot;
            app:navGraph=&quot;@navigation/mobile_navigation&quot; /&gt;
    
        &lt;com.google.android.material.bottomappbar.BottomAppBar
            android:id=&quot;@+id/bottom_appbar&quot;
            android:layout_width=&quot;match_parent&quot;
            android:layout_height=&quot;?android:attr/actionBarSize&quot;
            android:layout_gravity=&quot;bottom&quot; /&gt;
    
        &lt;com.google.android.material.floatingactionbutton.FloatingActionButton
            android:id=&quot;@+id/fab&quot;
            android:layout_width=&quot;wrap_content&quot;
            android:layout_height=&quot;wrap_content&quot;
            app:layout_anchor=&quot;@id/bottom_appbar&quot; /&gt;
    
    &lt;/androidx.coordinatorlayout.widget.CoordinatorLayout&gt;

**navigation.xml**

    &lt;navigation xmlns:android=&quot;http://schemas.android.com/apk/res/android&quot;
        xmlns:app=&quot;http://schemas.android.com/apk/res-auto&quot;
        xmlns:tools=&quot;http://schemas.android.com/tools&quot;
        android:id=&quot;@+id/mobile_navigation&quot;
        app:startDestination=&quot;@id/mainFragment&quot;&gt;
        &lt;fragment
            android:id=&quot;@+id/mainFragment&quot;
            android:name=&quot;com.example.MainFragment&quot;
            android:label=&quot;fragment_main&quot;
            tools:layout=&quot;@layout/fragment_main&quot; &gt;
            &lt;action
                android:id=&quot;@+id/toAccountFragment&quot;
                app:destination=&quot;@id/detailFragment&quot; /&gt;
        &lt;/fragment&gt;
        &lt;fragment
            android:id=&quot;@+id/detailFragment&quot;
            android:name=&quot;com.example.DetailFragment&quot;
            android:label=&quot;fragment_account&quot;
            tools:layout=&quot;@layout/fragment_detail&quot; /&gt;
    &lt;/navigation&gt;

So when start my app, **the title is &quot;MainActivity&quot;**. As usual it shows the `MainFragment` that contains the button to go to `DetailFragment`. In the `DialogFragment` I&#39;ve set the title as:

    getActivity().getSupportActionBar().setTitle(&quot;Detail&quot;);

**First Problem:** So clicking the button on the `MainFragment` to goto `DetailFragment`, it does go there and the title changes to &quot;Detail&quot;. But on clicking the back button, the **title changes to &quot;fragment_main&quot;**. So I added this line of code to `MainFragment`:

    @Override
    public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);
        // ...

        //Showing the title 
        Navigation.findNavController(view)
          .getCurrentDestination().setLabel(&quot;Hello&quot;);
    }

Now the while returning back from `DetailFragment` to `MainFragment` the title changes to &quot;Hello&quot;. But here comes the **second problem**, when I close the app and start again, the title changes back to &quot;MainActivity&quot; though it should be showing &quot;Hello&quot; instead, know?

Ok, then adding `setTitle(&quot;Hello&quot;)` in `MainFrgment` is not working too. For example, the activity starts and the title is &quot;Hello&quot;, go to `DetailsFragment` and press the back button again, the title goes back to &quot;fragment_main&quot;.

The only solution is to have both `setTitle(&quot;Hello&quot;)` along with `Navigation.findNavController(view).getCurrentDestination().setLabel(&quot;Hello&quot;)` in `MainFragment`.

So what is the proper way to show the title for fragments using Navigation Component?

  [1]: https://stackoverflow.com/questions/52483927/two-different-menus-for-top-app-bar-and-bottom-app-bar-with-navigation-component


How to set title in app bar with Navigation Architecture Component

I&#39;m using Android Studio 3.2 Canary 14 and [The Navigation Architecture Component][1]. With this you can define transition animations pretty much as you would when using Intents. 

But the animations are set as properties of the actions in the navigation graph, like so:

    &lt;fragment
        android:id=&quot;@+id/startScreenFragment&quot;
        android:name=&quot;com.example.startScreen.StartScreenFragment&quot;
        android:label=&quot;fragment_start_screen&quot;
        tools:layout=&quot;@layout/fragment_start_screen&quot; &gt;
      &lt;action
        android:id=&quot;@+id/action_startScreenFragment_to_findAddressFragment&quot;
        app:destination=&quot;@id/findAddressFragment&quot;
        app:enterAnim=&quot;@animator/slide_in_right&quot;
        app:exitAnim=&quot;@animator/slide_out_left&quot;
        app:popEnterAnim=&quot;@animator/slide_in_left&quot;
        app:popExitAnim=&quot;@animator/slide_out_right&quot;/&gt;
    &lt;/fragment&gt;

This gets tedious to define for all actions in the graph!

**Is there a way to define a set of animations as default, on actions?** 

I&#39;ve had no luck using styles for this.


  [1]: https://developer.android.com/topic/libraries/architecture/navigation/

How do I define default animations for Navigation Actions?

I tried to find a method in the new Navigation components but I didn&#39;t find anything about that. 

I have the current destination with :

    mainHostFragment.findNavController().currentDestination

But I can&#39;t get any reference to the displayed fragment.

How I can retrieve current fragment in NavHostFragment?

I&#39;ve been following the docs from [Navigation Architecture Component][1] to understand how this new navigation system works. 

To go/back from one screen to another you need a component which implements `NavHost` interface.

&gt; The NavHost is an empty view whereupon destinations are swapped in and
&gt; out as a user navigates through your app.


But, it seems that currently only Fragments implement `NavHost` 

&gt; The Navigation Architecture Component’s default NavHost implementation is NavHostFragment.


So, my questions are:

* Even if I have a very simple screen which can be implemented with an `Activity`, in order to work with this new navigation system, a `Fragment` needs to be hosted containing the actual view?

* Will `Activity` implement `NavHost` interface in a near future?
  

**--UPDATED--** 

Based on ianhanniballake&#39;s answer, I understand that every activity contains its own navigation graph. But if I want to go from one activity to another using the nav component (replacing &quot;old&quot; `startActivity` call), I can use `activity destinations`. What is `activity destinations` is not clear to me because the [docs for migration][2] don&#39;t go into any detail:

&gt; Separate Activities can then be linked by adding activity destinations to the navigation graph, replacing existing usages of startActivity() throughout the code base.

* Is there any benefit on using `ActivityNavigator` instead of `startActivity`? 
* What is the proper way to go from activities when using the nav component?  
  [1]: https://developer.android.com/topic/libraries/architecture/navigation/navigation-implementing
  [2]: https://developer.android.com/topic/libraries/architecture/navigation/navigation-migrate

Navigation Architecture Component - Activities

What is the difference between animation tags in latest Navigation Architecture Component? I got confused with `enterAnim` &amp; `popEnterAnim`. Similarly, `exitAnim` &amp; `popExitAnim`.

Any visual expansions is more than welcomed.

All Android Architecture-Navigation Solutions on Gang of Coders

Total of 21 Android Architecture-Navigation Solutions