I've upgraded to recently released navigation comp...

# android

[Daniele Segato]

I've upgraded to recently released navigation component alpha05 and this error popped up:

Unresolved reference. None of the following candidates is applicable because of receiver type mismatch:
public fun `Activity;`.findNavController(viewId: Int): `NavController;` defined in androidx.navigation
public fun `View;`.findNavController(): `NavController;` defined in androidx.navigation

This means my previously working code doesn't compile anymore on this stuff:

view.setOnClickListener {
    it.findNavController().navigate(somewhere)
}

cause it cant resolve findNavController() extension function.

I think it's a collision?

Checked the source code

package androidx.navigation

import android.view.View
/**
 * Find a [NavController] associated with a [View].
 *
 * Calling this on a View not within a [NavHost] will result in an
 * [IllegalStateException]
 */
fun View.findNavController(): NavController =
        Navigation.findNavController(this)

and

package androidx.navigation
import android.app.Activity
import android.support.annotation.IdRes
/**
 * 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)

these two collide I think and when you import androidx.navigation.findNavController it doesn't know which one to import?

[Daniele Segato]

I know I can just replace it with Navigation.findNavController(it). I've asked the question to learn more about this kind of situation.
How to handle collisions like this, how to avoid them etc...

[louiscad]

Isn't it in setOnClickListener { ... } nullable? Try with safe call (it?.findNavController())

[Daniele Segato]

Same thing happens, it is of type View! anyway, so yeah, can be Nullable but basically never is. And if i use it!! or it? nothing change

[Daniele Segato]

(I've created a bug report) https://issuetracker.google.com/issues/112806420

in the meanwhile I hope to learn more on how this works