IssueTracker

Component used: Navigation Version used: 2.3.2 Devices/Android versions reproduced on: N/A

The current implementation of the nav graph inflater uses Resources::obtainAttributes, which doesn't deeply resolve theme attributes, meaning the following won't work:

// in attrs.xml
<attr name="transitionDefaultEnter" format="reference"/>
<attr name="transitionDefaultExit" format="reference"/>
<attr name="transitionDefaultPopEnter" format="reference"/>
<attr name="transitionDefaultPopExit" format="reference"/>

<attr name="transitionModalEnter" format="reference"/>
<attr name="transitionModalExit" format="reference"/>
<attr name="transitionModalPopEnter" format="reference"/>
<attr name="transitionModalPopExit" format="reference"/>

// in themes.xml
<item name="transitionDefaultEnter">@anim/slide_in_from_right</item>
<item name="transitionDefaultPopExit">@anim/slide_out_to_right</item>
...

// in nav_main.xml
<action
   android:id="@+id/someActionId"
   app:destination="@id/someDestination"
   app:enterAnim="?attr/transitionDefaultEnter"
   app:exitAnim="?attr/transitionDefaultExit"
   app:popEnterAnim="?attr/transitionDefaultPopEnter"
   app:popExitAnim="?attr/transitionDefaultPopExit" />

<action
   android:id="@+id/someOtherActionId"
   app:destination="@id/someModalScreenDestination"
   app:enterAnim="?attr/transitionModalEnter"
   app:exitAnim="?attr/transitionModalExit"
   app:popEnterAnim="?attr/transitionModalPopEnter"
   app:popExitAnim="?attr/transitionModalPopExit" />

Obviously this functionality would have a lot of use when it comes to "theming" an app's motion (and defining different "categories" of motion for an app) as well as being able to change animations more easily from one place in much the same was as changing colors or other theme attribute values.

Is there a reason the NavInflater hasn't been set up to resolve these attributes?