Crash on screen rotation in ListPreferenceDialogFragmentCompat [122167543]

Fixed

Bug

Status Update

No update yet.

Description

al...@gmail.com

created issue #1

Jan 1, 2019 02:58AM

Stacktrace:

2018-12-31 18:56:12.569 5471-5471/com.supercilex.robotscouter.debug E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.supercilex.robotscouter.debug, PID: 5471
java.lang.NullPointerException: Attempt to invoke interface method 'androidx.preference.Preference androidx.preference.DialogPreference$TargetFragment.findPreference(java.lang.CharSequence)' on a null object reference
at androidx.preference.PreferenceDialogFragmentCompat.getPreference(PreferenceDialogFragmentCompat.java:177)
at androidx.preference.ListPreferenceDialogFragmentCompat.getListPreference(ListPreferenceDialogFragmentCompat.java:76)
at androidx.preference.ListPreferenceDialogFragmentCompat.onDialogClosed(ListPreferenceDialogFragmentCompat.java:104)
at androidx.preference.PreferenceDialogFragmentCompat.onDismiss(PreferenceDialogFragmentCompat.java:267)
at android.app.Dialog$ListenersHandler.handleMessage(Dialog.java:1393)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:193)
at android.app.ActivityThread.main(ActivityThread.java:6680)
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)

Comments

al...@gmail.com <al...@gmail.com> #2Jan 1, 2019 02:59AM

Yes, this is correct. Having individual navigation graphs on each activities overrides or disallow up navigation to the main activity.

lp...@google.com <lp...@google.com> #3Jan 2, 2019 01:58PM

Status: Duplicate of

120240628

I believe I have found the potential problem that is causing this:
// @ androidx.navigation.NavController
// line 124

// Now record the pop operation that we were sent
if (!mBackStack.isEmpty()) {
mBackStack.removeLast();
}
// We never want to leave NavGraphs on the top of the stack
while (!mBackStack.isEmpty()
&& mBackStack.peekLast() instanceof NavGraph) {
popBackStack();
}

the condition in while loop is never satisfied because of the above `if` statement above it has already removed the last item of the mBackStack (which was the NavGraph) and thus popBackStack() is never called again.

al...@gmail.com <al...@gmail.com> #4Jan 2, 2019 09:16PM

According to Ian Lake, NavigationUI does not support up navigation yet, that is why this is a feature request.

+Pedro Varela - we don't support navigating up through activities as part of NavigationUI yet, please star the feature request:

https://issuetracker.google.com/issues/79993862 (this issue)

lp...@google.com <lp...@google.com> Jan 3, 2019 01:55PM

Status: Assigned (reopened)

lp...@google.com <lp...@google.com> #5Jan 3, 2019 03:05PM

Ian Lake said Up navigation is not supported through activities, only through fragments.

hp...@gmail.com <hp...@gmail.com> #6Jan 3, 2019 06:49PM

With the introduction of AppBarConfiguration, this is now possible with the setupActionBarWithNavController method by using an empty set of top level destinations (to always show the up button) and then overriding onSupportNavigateUp() as per the documentation:

https://developer.android.com/topic/libraries/architecture/navigation/navigation-ui#action_bar

I'll leave this bug open as we still need an equivalent API for the Toolbar versions.

hp...@gmail.com <hp...@gmail.com> #7Jan 3, 2019 07:01PM

https://android-review.googlesource.com/846338 adds a setFallbackOnNavigateUpListener method on AppBarConfiguration that allows you to register an OnNavigateUpListener to handle cases where navController.navigateUp() return false.

This allows you to call onSupportNavigateUp() (or super.onSupportNavigateUp() if you're using an ActionBar) from that method to have your Up button transition between activities.

This will be available in 1.0.0-alpha09.

lp...@google.com <lp...@google.com> #8Jan 3, 2019 07:42PM

There is Jarks when implementing this way to navigate up between activities.

lp...@google.com <lp...@google.com> #9Jan 22, 2019 06:05PM

Marked as fixed.

This has been fixed and will be available in an upcoming release.

lb...@gmail.com <lb...@gmail.com> #10Jan 22, 2019 06:35PM

@9 Which one?

lp...@google.com <lp...@google.com> #11Jan 22, 2019 06:42PM

Both the Fragment issues and a workaround in Preference library to prevent this from happening in the future will be released.

lb...@gmail.com <lb...@gmail.com> #12Jan 22, 2019 06:46PM

@11 I mean in which version exactly should we expect it to happen? What would be in the gradle file?

lp...@google.com <lp...@google.com> #13Jan 22, 2019 06:49PM

alpha03, which is yet to be released.

lb...@gmail.com <lb...@gmail.com> #14Jan 22, 2019 07:13PM

@13 You mean :
implementation 'androidx.fragment:fragment:1.1.0-alpha03' ?

lp...@google.com <lp...@google.com> #15Jan 22, 2019 08:03PM

Oh I see - sorry.

The two fragment fixes will be available in androidx.fragment:fragment:1.1.0-alpha04
However, androidx.preference:preference:1.1.0-alpha03 will depend on fragment alpha04, so you only need to specify androidx.preference:preference:1.1.0-alpha03 to bring in these fixes and other changes in Preference.

lb...@gmail.com <lb...@gmail.com> #16Jan 22, 2019 08:28PM

@15 Thank you

hp...@gmail.com <hp...@gmail.com> #17Jan 25, 2019 03:24AM

nice! will test and provide feedback once the new versions are released. thanks!

hp...@gmail.com <hp...@gmail.com> #18Feb 13, 2019 03:55PM

sorry for the late feedback. I am done testing androidx.preference:preference:1.1.0-alpha03, and the bug is no longer present. I ran the linked sample project above on three devices: Samsung Galaxy J2 Prime running Android 6.0.1, Samsung Galaxy J2 Pro running Android 7.1.1, and a Samsung Galaxy J4+ running Android 8.1.0.

thanks for the fix!

lb...@gmail.com <lb...@gmail.com> #19Feb 13, 2019 05:08PM

@18 I think it might still exist, or something similar:

https://issuetracker.google.com/issues/124274583

lp...@google.com <lp...@google.com> #20Feb 13, 2019 05:28PM

Seems to be unrelated, will track that issue in that bug.

lb...@gmail.com <lb...@gmail.com> #21Feb 13, 2019 08:11PM

@20 I see. Will there be a new version of those soon, to fix similar issues?