Navigation Architecture Component - Dialog Fragments

Question

Is it possible to use the new Navigation Architecture Component with DialogFragment? Do I have to create a custom Navigator?

I would love to use them with the new fe

Answer 1

Yes. It's possible in the latest update of Navigation Component. You can check this link to have a clear concept. raywenderlich.com

Answer 2

May 2019 Update:

DialogFragment are now fully supported starting from Navigation 2.1.0, you can read more here and here

Old Answer for Navigation <= 2.1.0-alpha02:

I proceeded in this way:

1) Update Navigation library at least to version 2.1.0-alpha01 and copy both files of this modified gist in your project.

2) Then in your navigation host fragment, change the name parameter to your custom NavHostFragment

<fragment
    android:id="@+id/nav_host_fragment"
    android:name="com.example.app.navigation.MyNavHostFragment"
    app:defaultNavHost="true"
    app:navGraph="@navigation/nav_graph"
    android:layout_width="0dp"
    android:layout_height="0dp"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintTop_toBottomOf="@id/toolbar" />

3) Create your DialogFragment subclasses and add them to your nav_graph.xml with:

<dialog
    android:id="@+id/my_dialog"
    android:name="com.example.ui.MyDialogFragment"
    tools:layout="@layout/my_dialog" />

4) Now launch them from fragments or activity with

findNavController().navigate(R.id.my_dialog)

or similar methods.

Answer 3

I created custom navigator for DialogFragment.

Sample is here.
(It's just sample, so it might be any problem.)

@Navigator.Name("dialog_fragment")
class DialogNavigator(
    private val fragmentManager: FragmentManager
) : Navigator<DialogNavigator.Destination>() {

    companion object {
        private const val TAG = "dialog"
    }

    override fun navigate(destination: Destination, args: Bundle?, 
            navOptions: NavOptions?, navigatorExtras: Extras?) {
        val fragment = destination.createFragment(args)
       fragment.setTargetFragment(fragmentManager.primaryNavigationFragment, 
               SimpleDialogArgs.fromBundle(args).requestCode)
        fragment.show(fragmentManager, TAG)
        dispatchOnNavigatorNavigated(destination.id, BACK_STACK_UNCHANGED)
    }

    override fun createDestination(): Destination {
        return Destination(this)
    }

    override fun popBackStack(): Boolean {
        return true
    }

    class Destination(
            navigator: Navigator<out NavDestination>
    ) : NavDestination(navigator) {

        private var fragmentClass: Class<out DialogFragment>? = null

        override fun onInflate(context: Context, attrs: AttributeSet) {
            super.onInflate(context, attrs)
            val a = context.resources.obtainAttributes(attrs,
                    R.styleable.FragmentNavigator)
            a.getString(R.styleable.FragmentNavigator_android_name)
                    ?.let { className ->
                fragmentClass = parseClassFromName(context, className, 
                        DialogFragment::class.java)
            }
            a.recycle()
        }

        fun createFragment(args: Bundle?): DialogFragment {
            val fragment = fragmentClass?.newInstance()
                ?: throw IllegalStateException("fragment class not set")
            args?.let {
                fragment.arguments = it
            }
            return fragment
        }
    }
}

Answer 4

One option would be to just use a regular fragment and make it look similar to a dialog. I found it was not worth the hassle so I used the standard way using show(). If you insist See here for a way of doing it.

Answer 5

Yes. The framework is made in such a way that you can create a class extending the Navigator abstract class for the views that does not come out-of-the box and add it to your NavController with the method getNavigatorProvider().addNavigator(Navigator navigator)

If you are using the NavHostFragment, you will also need to extend it to add the custom Navigator or just create your own MyFragment implementing NavHost interface. It's so flexible that you can create your own xml parameters with custom attrs defined in values, like you do creating custom views. Something like this (not tested):

@Navigator.Name("dialog-fragment")
class DialogFragmentNavigator(
        val context: Context,
        private val fragmentManager: FragmentManager
) : Navigator<DialogFragmentNavigator.Destination>() {

    override fun navigate(destination: Destination, args: Bundle?,
                          navOptions: NavOptions?, navigatorExtras: Extras?
    ): NavDestination {
        val fragment = Class.forName(destination.name).newInstance() as DialogFragment
        fragment.show(fragmentManager, destination.id.toString())
        return destination
    }

    override fun createDestination(): Destination = Destination(this)

    override fun popBackStack() = fragmentManager.popBackStackImmediate()

    class Destination(navigator: DialogFragmentNavigator) : NavDestination(navigator) {

        // The value of <dialog-fragment app:name="com.example.MyFragmentDialog"/>
        lateinit var name: String

        override fun onInflate(context: Context, attrs: AttributeSet) {
            super.onInflate(context, attrs)
            val a = context.resources.obtainAttributes(
                    attrs, R.styleable.FragmentNavigator
            )
            name = a.getString(R.styleable.FragmentNavigator_android_name)
                    ?: throw RuntimeException("Error while inflating XML. " +
                            "`name` attribute is required")
            a.recycle()
        }
    }
}

Usage

my_navigation.xml

<?xml version="1.0" encoding="utf-8"?>
<navigation xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/navigation"
    app:startDestination="@id/navigation_home">

    <fragment
        android:id="@+id/navigation_assistant"
        android:name="com.example.ui.HomeFragment"
        tools:layout="@layout/home">
        <action
            android:id="@+id/action_nav_to_dialog"
            app:destination="@id/navigation_dialog" />
    </fragment>

    <dialog-fragment
        android:id="@+id/navigation_dialog"
        android:name="com.example.ui.MyDialogFragment"
        tools:layout="@layout/my_dialog" />

</navigation>    

The fragment that will navigate.

class HomeFragment : Fragment(), NavHost {

    private val navControllerInternal: NavController by lazy(LazyThreadSafetyMode.NONE){
        NavController(context!!)
    }

    override fun getNavController(): NavController = navControllerInternal

    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        // Built-in navigator for `fragment` XML tag
        navControllerInternal.navigatorProvider.addNavigator(
            FragmentNavigator(context!!, childFragmentManager, this.id)
        )
        // Your custom navigator for `dialog-fragment` XML tag
        navControllerInternal.navigatorProvider.addNavigator(
            DialogFragmentNavigator(context!!, childFragmentManager)
        )
        navControllerInternal.setGraph(R.navigation.my_navigation)
    }

    override fun onCreateView(inflater: LayoutInflater, 
                              container: ViewGroup?, savedInstanceState: Bundle?): View? {
        super.onCreateView(inflater, container, savedInstanceState)
        val view = inflater.inflate(R.layout.home)
        view.id = this.id

        view.button.setOnClickListener{
            getNavController().navigate(R.id.action_nav_to_dialog)
        }

        return view
    }
}

Answer 6

Version 2.1.0-alpha03 was Released so we can finally use DialogFragments. Unfortunately for me, I have some issues with the backstack when using cancelable dialogs. Probably I have a faulty implementation of my dialogs..

[LATER-EDIT] My implementation was good, the problem is related to Wrong dialog counting for DialogFragmentNavigator as is described in the issue tracker As a workaround you can have a look on my recommendation