How to close a parent fragment from child fragment in navigation component

Question

I'm creating an app that need to nested navigation graphs and a want to close a parent fragment from child fragment.

I can close a fragment by calling getActivity().getSupportFragmentManager().popBackStack(); with this i can only close the current top fragment in back stack.

in this picture i want to close Fragment2 from Framgent3.

EDIT:

I'm opening Fragment2 with: Navigation.findNavController(getView()).navigate(R.id.action_fragment1_to_fragment2);

Fragment1:

public class Fragment1 extends Fragment {

    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        return inflater.inflate(R.layout.fragment1, container, false);
    }

    @Override
    public void onActivityCreated(@Nullable Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);

        getView().findViewById(R.id.button).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Navigation.findNavController(v).navigate(R.id.action_fragment1_to_fragment2);
            }
        });
    }
}

Fragment1 layout:

<?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"
    android:background="@color/colorPrimaryDark">

    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Button"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />
    </androidx.constraintlayout.widget.ConstraintLayout>

Framgent2:

public class Fragment2 extends Fragment {

    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        return inflater.inflate(R.layout.fragment2, container, false);
    }

    @Override
    public void onActivityCreated(@Nullable Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
    }

    public void close () {
        getActivity().getSupportFragmentManager().popBackStack();
    }
}

in Fragment2 i have another graph, Fragment2 layout:

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.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"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toTopOf="parent">

    <fragment
        android:id="@+id/child_graph_base"
        android:name="androidx.navigation.fragment.NavHostFragment"
        android:layout_width="0dp"
        android:layout_height="0dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:defaultNavHost="true"
        app:navGraph="@navigation/child_graph" />
</android.support.constraint.ConstraintLayout>

Fragment3:

public class Fragment3 extends Fragment {

    @Nullable
    @Override
    public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        return inflater.inflate(R.layout.fragment3, container, false);
    }

    @Override
    public void onActivityCreated(@Nullable Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);
        getView().findViewById(R.id.button).setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                NavHostFragment navHostFragment = (NavHostFragment) getParentFragment();
                Fragment2 fragment2 = (Fragment2) navHostFragment.getParentFragment();
                fragment2.close();
            }
        });
    }
}

Fragment3 layout:

<?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"
    android:background="@color/colorPrimaryDark">

    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="Button"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>

Main Graph (MainActivity):

<?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/main_graph"
    app:startDestination="@id/fragment1">

    <fragment
        android:id="@+id/fragment1"
        android:name="alistar.navigation.fragments.Fragment1"
        android:label="fragment1"
        tools:layout="@layout/fragment1" >
        <action
            android:id="@+id/action_fragment1_to_fragment2"
            app:destination="@id/fragment2" />
    </fragment>
    <fragment
        android:id="@+id/fragment2"
        android:name="alistar.navigation.fragments.Fragment2"
        android:label="fragment2"
        tools:layout="@layout/fragment2" />
</navigation>

Child Graph (in Framgent2)

<?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/child_graph"
    app:startDestination="@id/fragment3">

    <fragment
        android:id="@+id/fragment3"
        android:name="alistar.navigation.fragments.Fragment3"
        android:label="fragment3"
        tools:layout="@layout/fragment3" />
</navigation>

You can use interface or [LocalBroadcastManager.](https://developer.android.com/reference/android/support/v4/content/LocalBroadcastManager) Also have a look [How to use LocalBroadcastManager?](https://stackoverflow.com/questions/8802157/how-to-use-localbroadcastmanager) — Rumit Patel, Jan 04 '19 at 11:10
@RumitPatel local broadcast manager is deprecated in androidx and replaced with LiveData — EpicPandaForce, Jan 04 '19 at 11:39

score 3 · Accepted Answer · answered Jan 04 '19 at 16:23

3

i solved the problem by calling close() method in the parent fragment (Fragment2) from Fragment3. i changed close method to this:

public void close () {
    Navigation.findNavController(getView()).popBackStack();
}

also i removed:

app:defaultNavHost="true"

from my child graph and worked OK!

answered Jan 04 '19 at 16:23

ali-star

706
1
10
19

How did you call Fragment 2 from Fragment 3? Can you share your approach? – pratz9999 Jan 16 '20 at 19:54
@pratz9999 use getParentFragment() method. – ali-star Jan 17 '20 at 20:27

Karan Harsh Wardhan · Answer 2 · 2019-01-04T11:43:17.577

0

include the graph of (frag2,frag3) in frag1's graph using include

<include app:graph="@navigation/frag1_graph"/>

and then:

add an action to your fragment3 with appropriate Destination and popUpTo arguments

<fragment
    android:id="@+id/Fragment3"
    android:name="whatever"
    android:label="whatever"
    tools:layout="@layout/whatever" >
     <action
        android:id="@+id/action_Fragment3_to_Fragmen1"
        app:destination="@id/Fragment1"
        app:launchSingleTop="true"
       app:popUpTo="@+id/Fragment1"
       app:popUpToInclusive="true" /> </fragment>

and then

findNavController(fragment).navigate(R.id.action_Fragment3_to_fragment1)

and then display fragment3 again. i think that's what you want right?

edited Jan 04 '19 at 11:43

answered Jan 04 '19 at 11:12

Karan Harsh Wardhan

1,096
9
22

i'm using navigation component. – ali-star Jan 04 '19 at 11:14
can't you just use the navigate functionality then? – Karan Harsh Wardhan Jan 04 '19 at 11:19
Fragment3 is not in the Fragment1 graph. – ali-star Jan 04 '19 at 11:28
why not add it to the graph? is there any reason for it? it is very simple if you add it to the graph. – Karan Harsh Wardhan Jan 04 '19 at 11:29
because i have some view's in Fragment2 and i need them. – ali-star Jan 04 '19 at 11:34
you can include frag2,frag3 graph in frag1's graph using include, then you can navigate the graph trivially – Karan Harsh Wardhan Jan 04 '19 at 11:42
frag1 and frag2 are in the same graph, but frag3 graph is in frag2. – ali-star Jan 04 '19 at 12:23
ok you need to post your xml, i am really confused by what your graph is – Karan Harsh Wardhan Jan 04 '19 at 12:24

How to close a parent fragment from child fragment in navigation component

2 Answers2