Crash when rotating screen on custom destination (catch 22 situation) [110763345]

Fixed

Bug

Status Update

No update yet.

Description

sl...@czerwinski.info.pl

created issue #1

Jun 25, 2018 10:25AM

Component used: Navigation Component
Version used: 1.0.0-alpha02
Devices/Android versions reproduced on: Emulator API 28, Samsung J5 API 25

Sample project attached.

I'm trying to create a custom Navigator and custom NavDestination that would animate ConstraintLayout (but any custom NavDestination would cause this issue).
Intended behaviour is shown in attached video: Layout_animations.webm

However, when I rotate the screen, while the navigation is on the custom destination, the application crashes.
The crash is caused by an unknown destination, which can only be added after custom navigator.
If I add custom destination in nav_main.xml, the app will also crash, because the navigator is not yet added.

This issue could be fixed by extending NavHostFragment, but I would need to override the whole onCreate() method.
I would need to add my custom navigator right after the line:
mNavController = new NavController(context);

I can think of 2 possible solutions in the library:
1. Delegate creating of NavController, so that a custom NavController can be provided in the XML layout file.
2. Call a new protected method "NavHostFragment.onNavControllerCreated(NavController)" right after the NavController is created, that could be overridden in a custom NavHostFragment, before the graph is created.

If there is any solution to my problem that I didn't think of, please provide a more exhaustive example in the documentation:

https://developer.android.com/topic/libraries/architecture/navigation/navigation-add-new

Stack trace:

2018-06-25 10:54:28.356 14543-14543/it.czerwinski.customnavigatorexample E/AndroidRuntime: FATAL EXCEPTION: main
Process: it.czerwinski.customnavigatorexample, PID: 14543
java.lang.RuntimeException: Unable to start activity ComponentInfo{it.czerwinski.customnavigatorexample/it.czerwinski.customnavigatorexample.MainActivity}: android.view.InflateException: Binary XML file line #10: Binary XML file line #10: Error inflating class fragment
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2925)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3060)
at android.app.ActivityThread.handleRelaunchActivityInner(ActivityThread.java:4792)
at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:4711)
at android.app.servertransaction.ActivityRelaunchItem.execute(ActivityRelaunchItem.java:69)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:110)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:70)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1800)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6649)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:826)
Caused by: android.view.InflateException: Binary XML file line #10: Binary XML file line #10: Error inflating class fragment
Caused by: android.view.InflateException: Binary XML file line #10: Error inflating class fragment
Caused by: java.lang.IllegalStateException: unknown destination during restore: it.czerwinski.customnavigatorexample:id/animatedLayoutDestination
at androidx.navigation.NavController.onGraphCreated(NavController.java:424)
at androidx.navigation.NavController.setGraph(NavController.java:386)
at androidx.navigation.NavController.restoreState(NavController.java:742)
at androidx.navigation.fragment.NavHostFragment.onCreate(NavHostFragment.java:215)
at androidx.fragment.app.Fragment.performCreate(Fragment.java:2400)
at androidx.fragment.app.FragmentManagerImpl.moveToState(FragmentManager.java:1418)
at androidx.fragment.app.FragmentManagerImpl.moveToState(FragmentManager.java:1684)
at androidx.fragment.app.FragmentManagerImpl.onCreateView(FragmentManager.java:3772)
at androidx.fragment.app.FragmentController.onCreateView(FragmentController.java:120)
at androidx.fragment.app.FragmentActivity.dispatchFragmentsOnCreateView(FragmentActivity.java:395)
at androidx.fragment.app.FragmentActivity.onCreateView(FragmentActivity.java:377)
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:780)
at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:730)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:863)
at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:824)
at android.view.LayoutInflater.inflate(LayoutInflater.java:515)
at android.view.LayoutInflater.inflate(LayoutInflater.java:423)
at android.view.LayoutInflater.inflate(LayoutInflater.java:374)
at androidx.appcompat.app.AppCompatDelegateImpl.setContentView(AppCompatDelegateImpl.java:467)
at androidx.appcompat.app.AppCompatActivity.setContentView(AppCompatActivity.java:140)
at it.czerwinski.customnavigatorexample.MainActivity.onCreate(MainActivity.kt:15)
at android.app.Activity.performCreate(Activity.java:7130)
at android.app.Activity.performCreate(Activity.java:7121)
at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1262)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2905)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:3060)
at android.app.ActivityThread.handleRelaunchActivityInner(ActivityThread.java:4792)
at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:4711)
2018-06-25 10:54:28.356 14543-14543/it.czerwinski.customnavigatorexample E/AndroidRuntime: at android.app.servertransaction.ActivityRelaunchItem.execute(ActivityRelaunchItem.java:69)
at android.app.servertransaction.TransactionExecutor.executeCallbacks(TransactionExecutor.java:110)
at android.app.servertransaction.TransactionExecutor.execute(TransactionExecutor.java:70)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1800)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:164)
at android.app.ActivityThread.main(ActivityThread.java:6649)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:826)

Sample Project.zip

20 MB

Download

Layout_animations.webm

1.8 MB

Download

Comments

il...@google.com <il...@google.com> Jun 25, 2018 11:01PM

Assigned to il...@google.com.

il...@google.com <il...@google.com> #2Jun 27, 2018 06:27PM

I have a same problem.
Internally, NavController#navigateUp() calls popBackStack().
And popBackStack() calls popBackStack(currentDestination.id, inclusive=true).

public boolean popBackStack() {
if (mBackStack.isEmpty()) {
// Nothing to pop if the back stack is empty
return false;
}
// Pop just the current destination off the stack
return popBackStack(getCurrentDestination().getId(), true); <--- this is cause.
}

So I think,
this problem can't be fixed without navigation cmpt. modification. :(

sl...@czerwinski.info.pl <sl...@czerwinski.info.pl> #3Jun 28, 2018 09:37AM

Component used: Navigation
Version used: 1.0.0-alpha09

But on alpha09 version, popBackStack() is implemented differently.

public boolean popBackStack() {
if (mBackStack.isEmpty()) {
throw new IllegalArgumentException("NavController back stack is empty");
}
boolean popped = false;
while (!mBackStack.isEmpty()) {
popped = mBackStack.removeLast().getNavigator().popBackStack(); <------ different
if (popped) {
break;
}
}
return popped;
}

Please restore to the upper codes. Or create a new option. :)

il...@google.com <il...@google.com> #4Jun 28, 2018 04:06PM

I found the commit.
(

https://android.googlesource.com/platform/frameworks/support/+/40067518406a59880b0dc47d3f6705b5d15e28fc%5E%21)

il...@google.com <il...@google.com> Oct 17, 2018 11:27PM

Accepted by il...@google.com.

ap...@google.com <ap...@google.com> #5Oct 18, 2018 04:25AM

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

commit 45818ac652ba3a43b07f980cf22ab78be886d81d
Author: Ian Lake <ilake@google.com>
Date: Wed Jan 30 10:45:37 2019

Ensure that popBackStack() only pops one Fragment

When two Fragments with the same destination ID are
both added to the back stack, they previously had an
identical back stack name in FragmentManager, which
incorrectly means that popBackStack with that name
would pop both off the back stack.

By changing how we generate back stack names for
FragmentNavigator, we ensure that each back stack
name is unique and that only one Fragment will be
popped for each popBackStack() call.

Test: new FragmentNavigatorTest test
Change-Id: I26bdaeb65620001a74165a166aa74fe48cb468e6
Fixes: 123552990

M navigation/fragment/src/androidTest/java/androidx/navigation/fragment/FragmentNavigatorTest.kt
M navigation/fragment/src/main/java/androidx/navigation/fragment/FragmentNavigator.java

https://android-review.googlesource.com/890733

https://goto.google.com/android-sha1/45818ac652ba3a43b07f980cf22ab78be886d81d

il...@google.com <il...@google.com> #6Oct 18, 2018 04:29AM

Marked as fixed.

This was regression introduced when fixing

https://issuetracker.google.com/issues/110893637 - it is now fixed internally and will be available in the next release of Navigation.

ap...@google.com <ap...@google.com> #7Oct 24, 2018 11:11AM

This is still not fixed. Steps to reproduce:

- Be on the initial Fragment (FragmentA)
- Press device back button (the back press will be consumed but nothing appears to happen)
- Click on a view that will cause an attempt to navigate to FragmentB
- Crash