I've bottom nav view with 3 item, My navGraph
looks like this:
<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"
app:startDestination="@id/nested_navigation"
<navigation
android:id="@+id/nested_navigation"
app:startDestination="@id/mainFragment" >
<fragment
android:id="@+id/mainFragment"
android:name="com.example.app.ui.main.MainFragment"
android:label="main_fragment"
tools:layout="@layout/main_fragment" />
<fragment
android:id="@+id/list"
android:name="com.example.app.ui.main.List"
android:label="fragment_news_list"
tools:layout="@layout/fragment_list" />
</navigation>
<fragment
android:id="@+id/settings"
android:name="com.example.app.ui.main.Settings"
android:label="Settings" />
</navigation>
The navigation in the bottom navigation view with the nested navGraph fragments work properly, but if I navigate to settings_fragment
, which is outside the nested navGraph, And I click on the other items/fragments I can't navigate to the other fragments and I basically stuck on this screen.
I checked what happened is if I put the settings_fragment
inside the nested navGraph, and it's works great.
How can I fix this problem?
btw - I'm pretty sure it's not related, but settings fragment is PreferenceScreen
layout that sits inside XML resource and not layout resource
My menu items:
<item
android:id="@+id/mainFragment"
android:icon="@drawable/ic_home_black_24dp"
android:title="@string/home"
app:showAsAction="ifRoom"
/>
<item
android:id="@+id/list"
android:icon="@drawable/ic_format_list_bulleted_black_24dp"
android:title="@string/news_list"
app:showAsAction="ifRoom"
/>
<item
android:id="@+id/settings"
android:icon="@drawable/ic_settings_black_24dp"
android:title="@string/settings"
app:showAsAction="ifRoom"
/>
The issue is to do with the structure of your nav graph.
Bottom navigation will only take into account the root elements.
- nested_navigation (root element) defaults to `mainFragment`
|- mainFragment (child element)
|- list (child element)
- settings (root element)
So given the above illustration, you will only be able to make use of the bottom navigation to navigate between settings
and nested_navigation
which in turn would be mainFragment
.
If you were to navigate between settings
and list
it would not have been possible.
Please take note that the id
of the menu items have to match the id
of the graph destination.
E.g.
<item
android:id="@+id/nested_navigation"
android:icon="@drawable/ic_home_black_24dp"
android:title="@string/home"
app:showAsAction="ifRoom" />
<item
android:id="@+id/settings"
android:icon="@drawable/ic_settings_black_24dp"
android:title="@string/settings"
app:showAsAction="ifRoom" />
Note the id
of the two elements match precisely the id
of the root
destinations.
Extra
Perhaps my other answer may be of help to complement the navigation flow -> How to switch to other fragment in different back stack using Navigation Component?
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