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

Solution 1:

First, add attributes app:popUpTo='your_nav_graph_id' and app:popUpToInclusive="true" to the action tag.

<fragment
    android:id="@+id/signInFragment"
    android:name="com.glee.incog2.android.fragment.SignInFragment"
    android:label="fragment_sign_in"
    tools:layout="@layout/fragment_sign_in" >
    <action
        android:id="@+id/action_signInFragment_to_usersFragment"
        app:destination="@id/usersFragment"
        app:launchSingleTop="true"
        app:popUpTo="@+id/main_nav_graph"
        app:popUpToInclusive="true" />
</fragment>

Second, navigate to the destination, using above action as parameter.

findNavController(fragment).navigate(
     SignInFragmentDirections.actionSignInFragmentToUserNameFragment())

See the docs for more information.

NOTE: If you navigate using method navigate(@IdRes int resId), you won't get the desired result. Hence, I used method navigate(@NonNull NavDirections directions).

Solution 2:

I think your question specifically pertains on how to use the Pop Behavior / Pop To / app:popUpTo (in xml)

In documentation,
Pop up to a given destination before navigating. This pops all non-matching destinations from the back stack until this destination is found.

Example (Simple Job hunting app)
my start_screen_nav graph is like this:

startScreenFragment (start) -> loginFragment -> EmployerMainFragment

                            -> loginFragment -> JobSeekerMainFragment

if I want to navigate to EmployerMainFragment and pop all including startScreenFragment then the code will be:

        <action
            android:id="@+id/action_loginFragment_to_employerMainFragment"
            app:destination="@id/employerMainFragment"

            app:popUpTo="@+id/startScreenFragment"
            app:popUpToInclusive="true" />

if I want to navigate to EmployerMainFragment and pop all excluding startScreenFragment then the code will be:

        <action
            android:id="@+id/action_loginFragment_to_employerMainFragment"
            app:destination="@id/employerMainFragment"

            app:popUpTo="@+id/startScreenFragment"/>

if I want to navigate to EmployerMainFragment and pop loginFragment but not startScreenFragment then the code will be:

        <action
            android:id="@+id/action_loginFragment_to_employerMainFragment"
            app:destination="@id/employerMainFragment"

            app:popUpTo="@+id/loginFragment"
            app:popUpToInclusive="true"/>

OR

        <action
            android:id="@+id/action_loginFragment_to_employerMainFragment"
            app:destination="@id/employerMainFragment"

            app:popUpTo="@+id/startScreenFragment"/>

Solution 3:

In my case i needed to remove everything in the back Stack before i open a new fragment so i used this code

navController.popBackStack(R.id.fragment_apps, true);
navController.navigate(R.id.fragment_company);

the first line removes the back Stack till it reaches the fragment specified in my case it's the home fragment so it's removes all the back stack completely , and when the user clicks back in the fragment_company he closes the app.

Solution 4:

NOTE: Clear task is deprecated, official description is

This method is deprecated. Use setPopUpTo(int, boolean) with the id of the NavController's graph and set inclusive to true.

Old Answer

If you don't wanna go through all that fuzz in code, you can simply check Clear Task in Launch Options in properties of the action.

Edit: As of Android Studio 3.2 Beta 5, Clear Task is no longer visible in Launch Options window, but you can still use it in navigation's XML code, in action tag, by adding

app:clearTask="true"