Fixed
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Comments
il...@google.com
ma...@gmail.com
If you need to add a custom Navigator but don't want to subclass NavHost (which we expect will be needed in most cases), the correct approach is to add it before you set your graph:
1) Don't use app:navGraph in your XML
2) Get a reference to your NavController
3) Add your Navigator to the NavController
4) Call setGraph on the NavController
This relies on the fact that NavController waits until the graph is set before restoring state / doing anything at all.
Technically, the createFragmentNavigator() call in NavHostFragment is already called at the same time as your proposed onNavControllerCreated() method so as a workaround, you could override that method, add your Navigator, then return super.createFragmentNavigator().
1) Don't use app:navGraph in your XML
2) Get a reference to your NavController
3) Add your Navigator to the NavController
4) Call setGraph on the NavController
This relies on the fact that NavController waits until the graph is set before restoring state / doing anything at all.
Technically, the createFragmentNavigator() call in NavHostFragment is already called at the same time as your proposed onNavControllerCreated() method so as a workaround, you could override that method, add your Navigator, then return super.createFragmentNavigator().
ch...@moqi.co.uk
The first solution does not work, because after screen rotation, the graph (probably a restored graph) is set when Activity.setContentView() is called.
The workaround with createFragmentNavigator() works, though it's not very elegant. Maybe the method could be renamed to createNavigators() and return a list or an array of Navigators?
Anyway, it is a good enough solution for now, so it is not very urgent.
In conclusion:
* I think that a better support for custom destinations should be provided before final release.
* I would suggest describing the "Add support for new destination types" section in the documentation in more details.
Thank you
The workaround with createFragmentNavigator() works, though it's not very elegant. Maybe the method could be renamed to createNavigators() and return a list or an array of Navigators?
Anyway, it is a good enough solution for now, so it is not very urgent.
In conclusion:
* I think that a better support for custom destinations should be provided before final release.
* I would suggest describing the "Add support for new destination types" section in the documentation in more details.
Thank you
il...@google.com
I suspect the issue you're running into for the first solution is that you're using the setGraph(R.navigation.graph) method, which does indeed cause it to automatically inflate the graph by id on rotation. Using setGraph(navGraph) where navGraph is a navGraph object you've inflated with navController.getNavInflater().inflate(R.navigation.graph) will never automatically be recreated.
Definitely something we can do better on though :)
Definitely something we can do better on though :)
ap...@google.com
Project: platform/frameworks/support
Branch: androidx-master-dev
commit a2e68921841727237528c4ac7076d50af64663c8
Author: Ian Lake <ilake@google.com>
Date: Wed Oct 17 16:46:28 2018
Make setGraph(int) and setGraph(NavGraph) act identically
Remove the auto restore functionality from NavController's
setGraph(int) method so that it functions identically to
setGraph(NavGraph).
This ensures that developers that manually are calling
setGraph() after adding custom navigators don't get
recreated too early.
Test: updated NavController test
BUG: 110763345
Change-Id: I51ae7c74451669d6bfed0fe84df445c2ff272e6e
M navigation/runtime/src/androidTest/java/androidx/navigation/NavControllerTest.kt
M navigation/runtime/src/main/java/androidx/navigation/NavController.java
https://android-review.googlesource.com/792819
https://goto.google.com/android-sha1/a2e68921841727237528c4ac7076d50af64663c8
Branch: androidx-master-dev
commit a2e68921841727237528c4ac7076d50af64663c8
Author: Ian Lake <ilake@google.com>
Date: Wed Oct 17 16:46:28 2018
Make setGraph(int) and setGraph(NavGraph) act identically
Remove the auto restore functionality from NavController's
setGraph(int) method so that it functions identically to
setGraph(NavGraph).
This ensures that developers that manually are calling
setGraph() after adding custom navigators don't get
recreated too early.
Test: updated NavController test
BUG: 110763345
Change-Id: I51ae7c74451669d6bfed0fe84df445c2ff272e6e
M navigation/runtime/src/androidTest/java/androidx/navigation/NavControllerTest.kt
M navigation/runtime/src/main/java/androidx/navigation/NavController.java
Description
android.arch.navigation:navigation-fragment-ktx
android.arch.navigation:navigation-ui-ktx
Version used:
1.0.0-alpha05
Devices/Android versions reproduced on:
-SM-A510F, Android 7.0
-Emulator x86_64 API 28
Sample project:
Description:
Having this structure:
nav_graph.xml
<navigation
android:id="@+id/nav_graph"
app:startDestination="@id/startFragment">
<fragment
android:id="@+id/startFragment"
android:name="com.example.navbug.StartFragment"
android:label="StartFragment"
tools:layout="@layout/fragment_start">
<action
android:id="@+id/action_startFragment_to_nested_nav_graph"
app:destination="@id/nested_nav_graph" />
</fragment>
<include app:graph="@navigation/nested_nav_graph" />
</navigation>
nested_nav_graph.xml
<navigation
android:id="@+id/nested_nav_graph"
app:startDestination="@id/nestedStartFragment">
<fragment
android:id="@+id/nestedStartFragment"
android:name="com.example.navbug.NestedStartFragment"
android:label="NestedStartFragment">
<action
android:id="@+id/action_nestedStartFragment_to_nestedSecondFragment"
app:destination="@id/nestedSecondFragment"
app:popUpTo="@+id/nestedStartFragment"
app:popUpToInclusive="true" />
</fragment>
<fragment
android:id="@+id/nestedSecondFragment"
android:name="com.example.navbug.NestedSecondFragment"
android:label="NestedSecondFragment" />
</navigation>
I want to achieve this navigation pattern:
StartFragment => NestedStartFragment => NestedSecondFragment =(back)=> StartFragment
I'm trying to implement this by setting the action NestedStartFragment=>NestedSecondFragment with the options [popUpTo=NestedStartFragment, popUpToInclusive=true], so that the resulting stack would be:
0. NestedSecondFragment
1. NestedNavGraph
2. StartFragment
3. NavGraph
When navigating from NestedStartFragment to NestedSecondFragment, the following execption occurs:
java.lang.IllegalArgumentException: Navigator androidx.navigation.fragment.FragmentNavigator@ccc9092 reported navigation to unknown destination id com.example.navbug:id/nestedSecondFragment
at androidx.navigation.NavController$2.onNavigatorNavigated(NavController.java:142)
at androidx.navigation.Navigator.dispatchOnNavigatorNavigated(Navigator.java:217)
at androidx.navigation.fragment.FragmentNavigator.navigate(FragmentNavigator.java:207)
at androidx.navigation.fragment.FragmentNavigator.navigate(FragmentNavigator.java:45)
at androidx.navigation.NavDestination.navigate(NavDestination.java:407)
at androidx.navigation.NavController.navigate(NavController.java:683)
at androidx.navigation.NavController.navigate(NavController.java:630)
at androidx.navigation.NavController.navigate(NavController.java:618)
at com.example.navbug.NestedStartFragment$onViewCreated$1.onClick(Fragments.kt:31)
at android.view.View.performClick(View.java:6597)
at android.view.View.performClickInternal(View.java:6574)
at android.view.View.access$3100(View.java:778)
at android.view.View$PerformClick.run(View.java:25885)
at android.os.Handler.handleCallback(Handler.java:873)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:193)
at android.app.ActivityThread.main(ActivityThread.java:6669)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)
Right before the navigation, the stack is:
0. NestedStartFragment
1. NestedNavGraph
2. StartFragment
3. NavGraph
When NestedStartFragment is popped on my request, NestedNavGraph is also popped because
"// We never want to leave NavGraphs on the top of the stack" (from NavController.onNavigatorNavigated)
with the effect that eventually the requested destination NestedSecondFragment is pruned from the graph and cannot be reached anymore.
Unless I'm doing something wrong, it seems that NavGraph automatic popping should be avoided if the final destination actually belongs to it.