是否可以使用Android导航架构组件（Android Jetpack）从“非开始”片段开始？

Question

so I have the following navigation graph:

Fragment A (start) --> Fragment B

So for some situations (firebase notifications), I need to start Fragment B directly, passing data from the notifications. Now, this works. However, when I press the back button, it results in a crash. Is it because the leading fragment ( Fragment A ) is not in the stack? If so, is there a way to properly handle this. Basically, I need the backPressed action to launch the start Fragment ( Fragment A ) in a situation where Fragment B is launched directly without passing through Fragment A .

Below is a snippet of my graph:

    <fragment
        android:id="@+id/homeFragment"
        android:name="dita.dev.myportal.ui.home.HomeFragment"
        android:label="Home"
        tools:layout="@layout/fragment_home">
        <action
            android:id="@+id/action_homeFragment_to_messageDetailFragment"
            app:destination="@id/messageDetailFragment"
            app:exitAnim="@anim/fade_out_animation" />
    </fragment>
    <fragment
        android:id="@+id/messageDetailFragment"
        android:name="dita.dev.myportal.ui.messages.details.MessageDetailFragment"
        android:label="Message"
        tools:layout="@layout/fragment_message_detail">
        <argument
            android:name="title"
            app:argType="string" />
        <argument
            android:name="message"
            app:argType="string" />
    </fragment>

Answer 1

I hope the link helps. https://developer.android.com/guide/navigation/navigation-deep-link

Deep links allow for synthetic back-stacks. Quoted from the website, "This means that when a user presses the Back button from a deep link destination, they navigate back up the navigation stack just as though they entered your app from its entry point." Maybe trying to create a deep link for Fragment B will work.