Is it possible to use DI with the androidx.navigation.NavController

Question

So, the title of this reflects the question. to obtain a link on a navigation controller (androidx.navigation.NavController) usually we use following code:

NavController navController = Navigation.findNavController(this, R.id.nav_host_frag);

Is it possible to inject a NavController using Dagger2 framework? (findNavController requires an activity or a view reference) Maybe it's a silly question and nobody injects the androidx.navigation.NavController, but nevertheless I decided to ask this question to be certain in my assumptions. Thanks ahead

Answer 1

I don't see why you would want to inject the NavController when there are methods for you to find it, also I would be concerned with using dependency injection due to holding a reference to an Activity.

Given you are working with an Activity you would normally find the controller by using the following method:

private val navController: NavController by lazy { findNavController(R.id.main_container) }

Now if we take a look at the source code for the method findNavController() you will notice that it uses an extension function and Navigation.findNavController(this, viewId).

/**
 * Find a [NavController] given the id of a View and its containing
 * [Activity].
 *
 * Calling this on a View that is not a [NavHost] or within a [NavHost]
 * will result in an [IllegalStateException]
 */
fun Activity.findNavController(@IdRes viewId: Int): NavController =
        Navigation.findNavController(this, viewId)

The only thing I would do to complement the above is to create another extension function to facilitate navigation from a Fragment.

fun Fragment.navigate(resId: Int, bundle: Bundle? = null) {
    NavHostFragment.findNavController(this).navigate(resId, bundle)
}

Then you could simply use within a Fragment:

navigate(
    R.id.action_fragmentA_to_FragmentB,
    bundleOf(Global.CAN_NAVIGATE_BACK to false)
)