IssueTracker

Hi all, I've implemented custom navigator to provide with Navigation Shared Elements transition ability https://github.com/lion4ik/aac-navigation-shared-elements-transition

Is there any info if it's planned to be implemented?

Support for shared elements for both activities and fragments has been added in https://android-review.googlesource.com/c/platform/frameworks/support/+/752138 through the introduction of a general purpose Navigator.Extras interface, providing a way to send a specific Navigator extra information at runtime (such as the Views you want included in shared element transitions).

This means for activity destinations, you can now provide any ActivityOptionsCompat instance you want alongside your navigate() call. For fragment destinations, you provide a map of shared elements. Documentation will be provided for both of these use cases.

This will be available in 1.0.0-alpha06.

Yes, it's worked in 1.0.0-alpha06, but only in forward direction...

Component used: Navigation
Version used: 1.0.0-alpha06
Devices/Android versions reproduced on: All

Fragment one: RecyclerView (GridLayoutManager). Transition name to ImageView is assigned in Adapter from model's name (unique)
Fragment two: Detail Fragment with ImageView and some text data. Transition name retrieved from argument's bundle.

Forward shared transition works excellent, but when I press "back" button there is no transition at all.
In NavHostActivity: override fun onSupportNavigateUp() = findNavController(R.id.nav_host_fragment).navigateUp()

In old paradigm

fragmentManager
            .beginTransaction()
            .addSharedElement(sharedImageView, transitionName)
all worked fine.

https://issuetracker.google.com/issues/116250233 has an example of Shared Element transitions that works in both directions, so this is likely due to the edge cases of shared element transitions and not something caused by navigation. Please open a new issue with a sample project if you're still running into issues.

Project: platform/frameworks/support
Branch: androidx-master-dev

commit 5e475aa0a00390755a9d4a9260c827b72ec81eb2
Author: Ian Lake <ilake@google.com>
Date:   Wed Nov 28 15:48:29 2018

    Pass Bundle of arguments to OnNavigatedListeners
   
    Instead of just passing the NavDestination,
    pass both the NavDestination and the (optional)
    Bundle of arguments. This allows listeners to
    dynamically update their content rather than only
    relying on the fixed data from the NavDestination.
   
    Test: testapp still works
    BUG: 80267266
    Change-Id: I80f0e65526711a2ba11b7a12fc907a1b9dbe83e9

A       navigation/common/src/main/java/androidx/navigation/NavBackStackEntry.java
M       navigation/integration-tests/testapp/src/main/java/androidx/navigation/testapp/NavigationActivity.kt
M       navigation/runtime/api/1.0.0-alpha08.txt
M       navigation/runtime/api/current.txt
M       navigation/runtime/src/main/java/androidx/navigation/NavController.java
M       navigation/ui/src/main/java/androidx/navigation/ui/AbstractAppBarOnNavigatedListener.java
M       navigation/ui/src/main/java/androidx/navigation/ui/CollapsingToolbarOnNavigatedListener.java
M       navigation/ui/src/main/java/androidx/navigation/ui/NavigationUI.java
M       navigation/ui/src/main/java/androidx/navigation/ui/ToolbarOnNavigatedListener.java

https://android-review.googlesource.com/837142
https://goto.google.com/android-sha1/5e475aa0a00390755a9d4a9260c827b72ec81eb2

This is fixed internally and will be available in 1.0.0-alpha08.

You'll be able to use labels such as "Hi {name}!" and the NavigationUI methods will automatically populate the {argName} elements with the appropriately named argument.

Comment #8,

Sounds good. I understand how I would pass the argument values during normal navigation, but how would I pass the argument to the starting fragment (set in `app:startDestination`)?

Passing arguments to the start destination of your graph was added in alpha07: https://issuetracker.google.com/issues/110300470

Comment #10,

Am I right in determining from that, that the starting fragment can only have it's title passed during initial creation[$1] or direct navigation[$2]?

Assuming I have a starting fragment labelled "A", and a second fragment somewhere in the graph labelled "B".

If I wish to change the title for the starting fragment "A" due to some action taken (e.g button press) on that ("A") fragment then I will need to find some other means of setting it, is this correct?

Same if I want the title on fragment "A" to change based on a choice made on fragment "B", but navigation back to "A"  (from "B") occurs via the back/up button or popping from the nav stack?

At the moment I'm setting the title for my starting fragment through a navigation listener (addOnNavigatedListener), and observing a LiveData change from my view model, as doing only one or the other results in situations where the title is not set. This means that for the majority of the time the title is set at least twice [$3].

$1) Presumably any one of these is only called once during the app's active lifetime, likely in `[Main]Activity.onCreate`, is that correct? As I understand it, using this feature would also require some alteration to how navigation is set up in the layout (.xml) files, right?
* `NavHostFragment.create(R.navigation.graph, args)`, or
* `navController.setGraph(R.navigation.graph, args)`, or
* `navController.setGraph(navGraph, args)`

$2) `navController.navigate(action)`

$3) The title is set by
1. the navigation component to whatever is in the label, and
2. the onNavigated listener, and
3. the observer on the LiveData.

While it's light work this repetition in setting the title seems wasteful.

I cannot quite put my finger on it but it seems strange to me that the navigation source gets to set the title as opposed to the destination setting the title based on some internal state.To make this work for me I would have to ensure that every source a fragment can be navigated from knows how to correctly determine the expected title, as opposed to that determination only being made in one place (the destination fragment).

Parameterized labels only pull from the arguments of the destination, yes.

If you need dynamic titles or more complicated logic, you should not use android:label in your graph and instead set the title yourself - NavigationUI only sets a title if the android:label exists.

Comment #12.
Thanks, I've removed the label from the fragment in the nav graph resource file. It was used as the default/fallback title until the title was set through the user's action.

This API was reviewed as part of "mass-review" of Navigation APIs at Donut Pod on December 4th.

Sorry to come up and notify you all but this is marked as fixed even though I found an issue with this approach:

 <fragment
            android:id="@+id/exampleFragment"
            android:name="com.example.ExampleFragment"
            android:label="{title}"
            tools:layout="@layout/fragment_examplel">

        <argument
                android:name="title"
                app:argType="string"/>

    </fragment>

This works fine, but as soon as the activity/view gets destroyed (e.g. rotating the device) the title gets cleared. let me know if I'm missing something but I'm using the safe args direction and passing the text as getString(R.string.example_title).

Re #15 - please file a new bug with a sample that reproduces your issue.

can i use argument from a parcelable type for the label ?
something like this ?
<fragment
    android:id="@+id/displayFragment"
    android:name="com.commonsware.jetpack.sampler.nav.DisplayFragment"
    android:label="{User.userName}" >
    <argument
      android:name="User"
     app:argType="com.example.app.User"/>
  </fragment>