How do I define default animations for Navigation Actions?

Here's my solution, and it worked well in my app.

public void navigate(int resId, Bundle bundle) {
        NavController navController = getNavController();
        if (navController == null) return;
        NavDestination currentNode;

        NavBackStackEntry currentEntry = navController.getCurrentBackStackEntry();
        if (currentEntry == null) currentNode = navController.getGraph();
        else currentNode = currentEntry.getDestination();

        final NavAction navAction = currentNode.getAction(resId);

        final NavOptions navOptions;
        if (navAction == null || navAction.getNavOptions() == null) navOptions = ExampleUtil.defaultNavOptions;
        else if (navAction.getNavOptions().getEnterAnim() == -1
                && navAction.getNavOptions().getPopEnterAnim() == -1
                && navAction.getNavOptions().getExitAnim() == -1
                && navAction.getNavOptions().getPopExitAnim() == -1) {
            navOptions = new NavOptions.Builder()
                    .setLaunchSingleTop(navAction.getNavOptions().shouldLaunchSingleTop())
                    .setPopUpTo(resId, navAction.getNavOptions().isPopUpToInclusive())
                    .setEnterAnim(ExampleUtil.defaultNavOptions.getEnterAnim())
                    .setExitAnim(ExampleUtil.defaultNavOptions.getExitAnim())
                    .setPopEnterAnim(ExampleUtil.defaultNavOptions.getPopEnterAnim())
                    .setPopExitAnim(ExampleUtil.defaultNavOptions.getPopExitAnim())
                    .build();
        } else navOptions = navAction.getNavOptions();
        navController.navigate(resId, bundle, navOptions);
    }

R.anim has the default animations defined (as final):

• nav_default_enter_anim

• nav_default_exit_anim

• nav_default_pop_enter_anim

• nav_default_pop_exit_anim

in order to change this behavior, you would have to use custom NavOptions,

because this is where those animation are being assigned to a NavAction.

one can assign these with the NavOptions.Builder:

protected NavOptions getNavOptions() {

    NavOptions navOptions = new NavOptions.Builder()
      .setEnterAnim(R.anim.default_enter_anim)
      .setExitAnim(R.anim.default_exit_anim)
      .setPopEnterAnim(R.anim.default_pop_enter_anim)
      .setPopExitAnim(R.anim.default_pop_exit_anim)
      .build();

    return navOptions;
}

most likely one would need to create a DefaultNavFragment, which extends class androidx.navigation.fragment (the documentation there does not seem completed yet).

So you can pass these NavOptions to the NavHostFragment like this:

NavHostFragment.findNavController(this).navigate(R.id.your_action_id, null, getNavOptions());

alternatively... when looking at the attrs.xml of that package; these animations are style-able:

<resources>
    <declare-styleable name="NavAction">
        <attr name="enterAnim" format="reference"/>
        <attr name="exitAnim" format="reference"/>
        <attr name="popEnterAnim" format="reference"/>
        <attr name="popExitAnim" format="reference"/>
        ...
    </declare-styleable>
</resources>

this means, one can define the according styles - and define these, as part of the theme...

one can define them in styles.xml:

<style name="Theme.Default" parent="Theme.AppCompat.Light.NoActionBar">

    <!-- these should be the correct ones -->
    <item name="NavAction_enterAnim">@anim/default_enter_anim</item>
    <item name="NavAction_exitAnim">@anim/default_exit_anim</item>
    <item name="NavAction_popEnterAnim">@anim/default_pop_enter_anim</item>
    <item name="NavAction_popExitAnim">@anim/default_pop_exit_anim</item>

</style>

---

One can also define the default animations in res/anim:

• res/anim/nav_default_enter_anim.xml
• res/anim/nav_default_exit_anim.xml
• res/anim/nav_default_pop_enter_anim.xml
• res/anim/nav_default_pop_exit_anim.xml

I found solution that requires extending NavHostFragment. It's similar to Link182 but less involved in code. Most often it will require to change all xml defaultNavHost fragments names from standard:

<fragment
    app:defaultNavHost="true"
    ...
    android:name="androidx.navigation.fragment.NavHostFragment"

to:

<fragment
    app:defaultNavHost="true"
    ...
    android:name="your.app.package.fragments.NavHostFragmentWithDefaultAnimations"

Code for NavHostFragmentWithDefaultAnimations:

package your.app.package.fragments

import android.content.Context
import android.os.Bundle
import androidx.fragment.app.FragmentManager
import androidx.navigation.*
import androidx.navigation.fragment.FragmentNavigator
import androidx.navigation.fragment.NavHostFragment
import your.app.package.R

// Those are navigation-ui (androidx.navigation.ui) defaults
// used in NavigationUI for NavigationView and BottomNavigationView.
// Set yours here
private val defaultNavOptions = navOptions {
    anim {
        enter = R.animator.nav_default_enter_anim
        exit = R.animator.nav_default_exit_anim
        popEnter = R.animator.nav_default_pop_enter_anim
        popExit = R.animator.nav_default_pop_exit_anim
    }
}

private val emptyNavOptions = navOptions {}

class NavHostFragmentWithDefaultAnimations : NavHostFragment() {

    override fun onCreateNavController(navController: NavController) {
        super.onCreateNavController(navController)
        navController.navigatorProvider.addNavigator(
            // this replaces FragmentNavigator
            FragmentNavigatorWithDefaultAnimations(requireContext(), childFragmentManager, id)
        )
    }

}

/**
 * Needs to replace FragmentNavigator and replacing is done with name in annotation.
 * Navigation method will use defaults for fragments transitions animations.
 */
@Navigator.Name("fragment")
class FragmentNavigatorWithDefaultAnimations(
    context: Context,
    manager: FragmentManager,
    containerId: Int
) : FragmentNavigator(context, manager, containerId) {

    override fun navigate(
        destination: Destination,
        args: Bundle?,
        navOptions: NavOptions?,
        navigatorExtras: Navigator.Extras?
    ): NavDestination? {
        // this will try to fill in empty animations with defaults when no shared element transitions are set
        // https://developer.android.com/guide/navigation/navigation-animate-transitions#shared-element
        val shouldUseTransitionsInstead = navigatorExtras != null
        val navOptions = if (shouldUseTransitionsInstead) navOptions
        else navOptions.fillEmptyAnimationsWithDefaults()
        return super.navigate(destination, args, navOptions, navigatorExtras)
    }

    private fun NavOptions?.fillEmptyAnimationsWithDefaults(): NavOptions =
        this?.copyNavOptionsWithDefaultAnimations() ?: defaultNavOptions

    private fun NavOptions.copyNavOptionsWithDefaultAnimations(): NavOptions =
        let { originalNavOptions ->
            navOptions {
                launchSingleTop = originalNavOptions.shouldLaunchSingleTop()
                popUpTo(originalNavOptions.popUpTo) {
                    inclusive = originalNavOptions.isPopUpToInclusive
                }
                anim {
                    enter =
                        if (originalNavOptions.enterAnim == emptyNavOptions.enterAnim) defaultNavOptions.enterAnim
                        else originalNavOptions.enterAnim
                    exit =
                        if (originalNavOptions.exitAnim == emptyNavOptions.exitAnim) defaultNavOptions.exitAnim
                        else originalNavOptions.exitAnim
                    popEnter =
                        if (originalNavOptions.popEnterAnim == emptyNavOptions.popEnterAnim) defaultNavOptions.popEnterAnim
                        else originalNavOptions.popEnterAnim
                    popExit =
                        if (originalNavOptions.popExitAnim == emptyNavOptions.popExitAnim) defaultNavOptions.popExitAnim
                        else originalNavOptions.popExitAnim
                }
            }
        }

}

You can change animations in nav graph xml or in code through passing navOptions. To disable default animations pass navOptions with anim values of 0 or pass navigatorExtras (setting shared transitions).

Tested for version:

implementation "androidx.navigation:navigation-fragment-ktx:2.3.1"
implementation "androidx.navigation:navigation-ui-ktx:2.3.1"

For version 2.5.2

fun navigate(
        entries: List<NavBackStackEntry>,
        navOptions: NavOptions?,
        navigatorExtras: Navigator.Extras?) 

has to be override as well.