使用 arguments 的多模块 android 架构中的导航

Question

Since the navigation files are in app module, feature modules won't have access to the Args file. Is there any workaround for that?

example: if I have a fragment which accepts email and password like so

<fragment
        android:id="@+id/navigation_sample"
        android:name="SampleFragment">
        <argument
            android:name="email"
            app:argType="string" />
        <argument
            android:name="password"
            app:argType="string" />
    </fragment>

I would have a SampleFragmentArgs generated which could be used to navigate

findnavController.navigate(R.id.navigation_sample, SampleFragmentArgs(email, password).toBundle)

But I can use this only from app module not in a feature module

Answer 1

It depends on what you call a "feature module", however I'm assuming that should be android library.

This is the setup that works:

1. Say your android library is called "mylibrary"
2. Your "app" module naturally should have the above as dependency
3. Your "mylibrary" should have apply plugin: "androidx.navigation.safeargs.kotlin" and corresponding setting in classpath of library top level build.gradle
4. Let's declare navigation graph inside library (say, mylibrary_graph.xml with id myLibraryGraph), just like you'd do in "app" module - and let's assume it has your "SampleFragment" as starting point, with all those arguments listed.
5. Let's say your "app" module has some navigation graph and let's include "mylibrary_graph.xml" as nested there ( <include app:graph="@navigation/mylibrary_graph" /> )
6. Let's say your "app" module nav graph in question has some fragment that needs to jump to your "SampleFragment" inside your android library. We'll declare it like this (pseudo code):

    <fragment
        android:id="@+id/HelloWorldFragment"
        android:name="..."
        android:label="..."
        tools:layout="...">

        <action
            android:id="@+id/jumpToSampleFragment"
            app:destination="@+id/myLibraryGraph">

          <argument
              android:name="email"
              app:argType="string" />
          <argument
              android:name="password"
              app:argType="string" />
        </action>
    </fragment>

7. Finally, you can then do this inside your HelloWorldFragment: findNavController().navigate(HelloWorldFragmentDirections.jumpToSampleFragment("oh@acme.com", "nimda"))

As one can see it works but there is somewhat minor inconvenience of declaring arguments in 2 places.