Fixed
Status Update
Comments
[Deleted User] <[Deleted User]> #2
We have same issue.
Version used: WorkManager 2.1.0-alpha01
Devices/Android versions reproduced on: mostly Android 5 & 6
Fatal Exception: java.lang.RuntimeException: Error receiving broadcast Intent { act=android.net.conn.CONNECTIVITY_CHANGE flg=0x4000010 (has extras) } in androidx.work.impl.constraints.trackers.NetworkStateTracker$NetworkStateBroadcastReceiver@c5142c8
at android.app.LoadedApk$ReceiverDispatcher$Args.run(LoadedApk.java:876)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5254)
at java.lang.reflect.Method.invoke(Method.java)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:902)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:697)
Caused by java.util.concurrent.RejectedExecutionException: Task java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask@64a6d62 rejected from java.util.concurrent.ScheduledThreadPoolExecutor@16d09ef3[Terminated, pool size = 0, active threads = 0, queued tasks = 0, completed tasks = 0]
at java.util.concurrent.ThreadPoolExecutor$AbortPolicy.rejectedExecution(ThreadPoolExecutor.java:2011)
at java.util.concurrent.ThreadPoolExecutor.reject(ThreadPoolExecutor.java:793)
at java.util.concurrent.ScheduledThreadPoolExecutor.delayedExecute(ScheduledThreadPoolExecutor.java:298)
at java.util.concurrent.ScheduledThreadPoolExecutor.schedule(ScheduledThreadPoolExecutor.java:503)
at java.util.concurrent.Executors$DelegatedScheduledExecutorService.schedule(Executors.java:644)
at androidx.work.impl.background.systemalarm.WorkTimer.startTimer(WorkTimer.java:82)
at androidx.work.impl.background.systemalarm.DelayMetCommandHandler.onAllConstraintsMet(DelayMetCommandHandler.java:100)
at androidx.work.impl.constraints.WorkConstraintsTracker.onConstraintMet(WorkConstraintsTracker.java:150)
at androidx.work.impl.constraints.controllers.ConstraintController.updateCallback(ConstraintController.java:134)
at androidx.work.impl.constraints.controllers.ConstraintController.onConstraintChanged(ConstraintController.java:141)
at androidx.work.impl.constraints.trackers.ConstraintTracker.setState(ConstraintTracker.java:103)
at androidx.work.impl.constraints.trackers.NetworkStateTracker$NetworkStateBroadcastReceiver.onReceive(NetworkStateTracker.java:170)
at android.app.LoadedApk$ReceiverDispatcher$Args.run(LoadedApk.java:866)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5254)
at java.lang.reflect.Method.invoke(Method.java)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:902)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:697)
Version used: WorkManager 2.1.0-alpha01
Devices/Android versions reproduced on: mostly Android 5 & 6
Fatal Exception: java.lang.RuntimeException: Error receiving broadcast Intent { act=android.net.conn.CONNECTIVITY_CHANGE flg=0x4000010 (has extras) } in androidx.work.impl.constraints.trackers.NetworkStateTracker$NetworkStateBroadcastReceiver@c5142c8
at android.app.LoadedApk$ReceiverDispatcher$Args.run(LoadedApk.java:876)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5254)
at java.lang.reflect.Method.invoke(Method.java)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:902)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:697)
Caused by java.util.concurrent.RejectedExecutionException: Task java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask@64a6d62 rejected from java.util.concurrent.ScheduledThreadPoolExecutor@16d09ef3[Terminated, pool size = 0, active threads = 0, queued tasks = 0, completed tasks = 0]
at java.util.concurrent.ThreadPoolExecutor$AbortPolicy.rejectedExecution(ThreadPoolExecutor.java:2011)
at java.util.concurrent.ThreadPoolExecutor.reject(ThreadPoolExecutor.java:793)
at java.util.concurrent.ScheduledThreadPoolExecutor.delayedExecute(ScheduledThreadPoolExecutor.java:298)
at java.util.concurrent.ScheduledThreadPoolExecutor.schedule(ScheduledThreadPoolExecutor.java:503)
at java.util.concurrent.Executors$DelegatedScheduledExecutorService.schedule(Executors.java:644)
at androidx.work.impl.background.systemalarm.WorkTimer.startTimer(WorkTimer.java:82)
at androidx.work.impl.background.systemalarm.DelayMetCommandHandler.onAllConstraintsMet(DelayMetCommandHandler.java:100)
at androidx.work.impl.constraints.WorkConstraintsTracker.onConstraintMet(WorkConstraintsTracker.java:150)
at androidx.work.impl.constraints.controllers.ConstraintController.updateCallback(ConstraintController.java:134)
at androidx.work.impl.constraints.controllers.ConstraintController.onConstraintChanged(ConstraintController.java:141)
at androidx.work.impl.constraints.trackers.ConstraintTracker.setState(ConstraintTracker.java:103)
at androidx.work.impl.constraints.trackers.NetworkStateTracker$NetworkStateBroadcastReceiver.onReceive(NetworkStateTracker.java:170)
at android.app.LoadedApk$ReceiverDispatcher$Args.run(LoadedApk.java:866)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5254)
at java.lang.reflect.Method.invoke(Method.java)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:902)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:697)
il...@google.com <il...@google.com>
[Deleted User] <[Deleted User]> #3
liujian16@: Are you sure this is happening on Android 6? Because the stack trace points to DelayMetCommandHandler (which is something that the AlarmManager based implementation uses) which is only used on API <= 22.
nihansin@: Sorry its not clear what you meant by
"WorkManager 2.1.0-alpha01
I know 2.1.0-alpha02 is out but I cannot test it as I CANNOT reproduce this issue on both alpha01 and 02."
Did you mean that you cannot reproduce this on your own but you see this happen in production ?
My guess is something like this might be happening:
If you have a Worker in RUNNING state, and you have been asked to stop (either because constraints are no longer met / or if you called cancel()) your Worker still needs to cooperatively cancel.
If your Worker never stops running, then WorkTimer will try and shutdown your Worker again (in 10 minutes). This time that will fail, because the Executor has already been shutdown.
This typically stems from a bug in your code (because your Worker never stopped).
Can you please turn on WorkManager's logging so it will better help us diagnose the problem ?
For this you need to use custom initialization. Something like:
Configuration configuration = new Configuration.Builder()
.setMinimumLoggingLevel(Log.VERBOSE)
.build();
WorkManager.initialize(context, configuration);
Make sure you disable the default initializer.
nihansin@: Sorry its not clear what you meant by
"WorkManager 2.1.0-alpha01
I know 2.1.0-alpha02 is out but I cannot test it as I CANNOT reproduce this issue on both alpha01 and 02."
Did you mean that you cannot reproduce this on your own but you see this happen in production ?
My guess is something like this might be happening:
If you have a Worker in RUNNING state, and you have been asked to stop (either because constraints are no longer met / or if you called cancel()) your Worker still needs to cooperatively cancel.
If your Worker never stops running, then WorkTimer will try and shutdown your Worker again (in 10 minutes). This time that will fail, because the Executor has already been shutdown.
This typically stems from a bug in your code (because your Worker never stopped).
Can you please turn on WorkManager's logging so it will better help us diagnose the problem ?
For this you need to use custom initialization. Something like:
Configuration configuration = new Configuration.Builder()
.setMinimumLoggingLevel(Log.VERBOSE)
.build();
WorkManager.initialize(context, configuration);
Make sure you disable the default initializer.
il...@google.com <il...@google.com> #4
I will investigate this further on my end as well.
[Deleted User] <[Deleted User]> #5
Yes, I meant that I cannot reproduce it in my tests.
Here are some points.
- I skip the job if there is an already active job when doWork is called.
- I am never call cancell and I exit with success if job takes longer than
9 minutes. However, I do do batch processing and it may be that one of the
runs in the batch might have taken more than 10 minutes.
On Thu, 23 May 2019, 18:06 , <buganizer-system@google.com> wrote:
Here are some points.
- I skip the job if there is an already active job when doWork is called.
- I am never call cancell and I exit with success if job takes longer than
9 minutes. However, I do do batch processing and it may be that one of the
runs in the batch might have taken more than 10 minutes.
On Thu, 23 May 2019, 18:06 , <buganizer-system@google.com> wrote:
mi...@gmail.com <mi...@gmail.com> #6
"I skip the job if there is an already active job when doWork is called."
What do you mean by that ?
What kind of result are you returning ?
"I am never call cancell and I exit with success if job takes longer than
9 minutes. "
How are you accounting for time ? Are you regularly polling inside your Worker ?
What do you mean by that ?
What kind of result are you returning ?
"I am never call cancell and I exit with success if job takes longer than
9 minutes. "
How are you accounting for time ? Are you regularly polling inside your Worker ?
[Deleted User] <[Deleted User]> #7
I have a utility method to check the status of the jobs by tag
fun Worker.isRunning(tag: String): Boolean {
val instance = androidx.work.WorkManager.getInstance(applicationContext)
val statuses = instance.getWorkInfosByTag(tag)
try {
var running = false
val workInfoList = statuses.get()
for (workInfo in workInfoList) {
val state = workInfo.state
running = (state == WorkInfo.State.RUNNING)
}
return running
} catch (e: ExecutionException) {
e.printStackTrace()
return false
} catch (e: InterruptedException) {
e.printStackTrace()
return false
}
}
This is a periodic work. I always return Result.success() regardless what I
do when doWork run.
I assign current millis to a value in the beginning of doWork, call my
method that does what I want to do and check time on each loop.
My method is a simple for each loop that pulls a list from app dB and goes
through items.
On Thu, 23 May 2019, 18:20 , <buganizer-system@google.com> wrote:
fun Worker.isRunning(tag: String): Boolean {
val instance = androidx.work.WorkManager.getInstance(applicationContext)
val statuses = instance.getWorkInfosByTag(tag)
try {
var running = false
val workInfoList = statuses.get()
for (workInfo in workInfoList) {
val state = workInfo.state
running = (state == WorkInfo.State.RUNNING)
}
return running
} catch (e: ExecutionException) {
e.printStackTrace()
return false
} catch (e: InterruptedException) {
e.printStackTrace()
return false
}
}
This is a periodic work. I always return Result.success() regardless what I
do when doWork run.
I assign current millis to a value in the beginning of doWork, call my
method that does what I want to do and check time on each loop.
My method is a simple for each loop that pulls a list from app dB and goes
through items.
On Thu, 23 May 2019, 18:20 , <buganizer-system@google.com> wrote:
il...@google.com <il...@google.com> #8
Can you please send us a sample app? Failing that, can you send us an unobfuscated stacktrace?
mi...@gmail.com <mi...@gmail.com> #9
Was it addressed to me? Unfortunately I cannot reproduce it on my test
devices at all.
I use R8 now. I'll try deobfuscate with prouguard.
Here is my code that crash originates
class PeriodicUploadWorker(context: Context, workerParams:
WorkerParameters) : Worker(context, workerParams) {
private val workManagerTimeLimit = 570000L //WorkManager limits
execution time to 10 minutes! We stop at 9.5 minutes just in case
private val LOG_TAG = "PeriodicUploadWorker"
override fun doWork(): Result {
if (Cloud2Logger.INSTANCE.DEBUG) {
Cloud2Logger.INSTANCE.log(LOG_TAG, "PeriodicUploadWorker run @
${DateFormat.getDateTimeInstance(DateFormat.LONG,
DateFormat.LONG).format(System.currentTimeMillis())}")
}
val delayedOneTimeUploadJobWorkRunning =
isRunning(CloudQueue.delayedOneTimeUploadJobWorkTag)
val periodicDeleteJobRunning =
isRunning(CloudQueue.periodicDeleteJobWorkTag)
val manualOneTimeUploadJobRunning =
isRunning(CloudQueue.manualOneTimeUploadJobWorkTag)
val isAnyWorkerRunning = delayedOneTimeUploadJobWorkRunning ||
periodicDeleteJobRunning || manualOneTimeUploadJobRunning
if (!isAnyWorkerRunning) {
CloudManagerProvider.getInstance(applicationContext).upload(workManagerTimeLimit)
} else {
if (Cloud2Logger.INSTANCE.DEBUG) {
Cloud2Logger.INSTANCE.log(LOG_TAG, "Skipped job as a worker
is already running")
}
}
return Result.success()
}
On Thu, 23 May 2019, 18:51 , <buganizer-system@google.com> wrote:
devices at all.
I use R8 now. I'll try deobfuscate with prouguard.
Here is my code that crash originates
class PeriodicUploadWorker(context: Context, workerParams:
WorkerParameters) : Worker(context, workerParams) {
private val workManagerTimeLimit = 570000L //WorkManager limits
execution time to 10 minutes! We stop at 9.5 minutes just in case
private val LOG_TAG = "PeriodicUploadWorker"
override fun doWork(): Result {
if (Cloud2Logger.INSTANCE.DEBUG) {
Cloud2Logger.INSTANCE.log(LOG_TAG, "PeriodicUploadWorker run @
${DateFormat.getDateTimeInstance(DateFormat.LONG,
DateFormat.LONG).format(System.currentTimeMillis())}")
}
val delayedOneTimeUploadJobWorkRunning =
isRunning(CloudQueue.delayedOneTimeUploadJobWorkTag)
val periodicDeleteJobRunning =
isRunning(CloudQueue.periodicDeleteJobWorkTag)
val manualOneTimeUploadJobRunning =
isRunning(CloudQueue.manualOneTimeUploadJobWorkTag)
val isAnyWorkerRunning = delayedOneTimeUploadJobWorkRunning ||
periodicDeleteJobRunning || manualOneTimeUploadJobRunning
if (!isAnyWorkerRunning) {
CloudManagerProvider.getInstance(applicationContext).upload(workManagerTimeLimit)
} else {
if (Cloud2Logger.INSTANCE.DEBUG) {
Cloud2Logger.INSTANCE.log(LOG_TAG, "Skipped job as a worker
is already running")
}
}
return Result.success()
}
On Thu, 23 May 2019, 18:51 , <buganizer-system@google.com> wrote:
il...@google.com <il...@google.com> #10
Thanks, we will wait for your unobfuscated stacktraces.
mi...@gmail.com <mi...@gmail.com> #11
Here it is
Fatal Exception: java.lang.RuntimeException: Error receiving broadcast Intent { act=android.net.conn.CONNECTIVITY_CHANGE flg=0x4000010 (has extras) } in androidx.work.impl.constraints.trackers.NetworkStateTracker$NetworkStateBroadcastReceiver@c5142c8
at android.app.LoadedApk$ReceiverDispatcher$Args.run(LoadedApk.java:876)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5254)
at java.lang.reflect.Method.invoke(Method.java)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:902)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:697)
Caused by java.util.concurrent.RejectedExecutionException: Task java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask@64a6d62 rejected from java.util.concurrent.ScheduledThreadPoolExecutor@16d09ef3[Terminated, pool size = 0, active threads = 0, queued tasks = 0, completed tasks = 0]
at java.util.concurrent.ThreadPoolExecutor$AbortPolicy.rejectedExecution(ThreadPoolExecutor.java:2011)
at java.util.concurrent.ThreadPoolExecutor.reject(ThreadPoolExecutor.java:793)
at java.util.concurrent.ScheduledThreadPoolExecutor.delayedExecute(ScheduledThreadPoolExecutor.java:298)
at java.util.concurrent.ScheduledThreadPoolExecutor.schedule(ScheduledThreadPoolExecutor.java:503)
at java.util.concurrent.Executors$DelegatedScheduledExecutorService.schedule(Executors.java:644)
at androidx.work.impl.background.systemalarm.WorkTimer.startTimer(WorkTimer.java:82)
at androidx.work.impl.background.systemalarm.DelayMetCommandHandler.onAllConstraintsMet(DelayMetCommandHandler.java:100)
at androidx.work.impl.constraints.WorkConstraintsTracker.onConstraintMet(WorkConstraintsTracker.java:150)
at androidx.work.impl.constraints.controllers.ConstraintController.updateCallback(ConstraintController.java:134)
at androidx.work.impl.constraints.controllers.ConstraintController.onConstraintChanged(ConstraintController.java:141)
at androidx.work.impl.constraints.trackers.ConstraintTracker.setState(ConstraintTracker.java:103)
at androidx.work.impl.constraints.trackers.NetworkStateTracker$NetworkStateBroadcastReceiver.onReceive(NetworkStateTracker.java:170)
at android.app.LoadedApk$ReceiverDispatcher$Args.run(LoadedApk.java:866)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5254)
at java.lang.reflect.Method.invoke(Method.java)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:902)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:697)
Fatal Exception: java.lang.RuntimeException: Error receiving broadcast Intent { act=android.net.conn.CONNECTIVITY_CHANGE flg=0x4000010 (has extras) } in androidx.work.impl.constraints.trackers.NetworkStateTracker$NetworkStateBroadcastReceiver@c5142c8
at android.app.LoadedApk$ReceiverDispatcher$Args.run(LoadedApk.java:876)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5254)
at java.lang.reflect.Method.invoke(Method.java)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:902)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:697)
Caused by java.util.concurrent.RejectedExecutionException: Task java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask@64a6d62 rejected from java.util.concurrent.ScheduledThreadPoolExecutor@16d09ef3[Terminated, pool size = 0, active threads = 0, queued tasks = 0, completed tasks = 0]
at java.util.concurrent.ThreadPoolExecutor$AbortPolicy.rejectedExecution(ThreadPoolExecutor.java:2011)
at java.util.concurrent.ThreadPoolExecutor.reject(ThreadPoolExecutor.java:793)
at java.util.concurrent.ScheduledThreadPoolExecutor.delayedExecute(ScheduledThreadPoolExecutor.java:298)
at java.util.concurrent.ScheduledThreadPoolExecutor.schedule(ScheduledThreadPoolExecutor.java:503)
at java.util.concurrent.Executors$DelegatedScheduledExecutorService.schedule(Executors.java:644)
at androidx.work.impl.background.systemalarm.WorkTimer.startTimer(WorkTimer.java:82)
at androidx.work.impl.background.systemalarm.DelayMetCommandHandler.onAllConstraintsMet(DelayMetCommandHandler.java:100)
at androidx.work.impl.constraints.WorkConstraintsTracker.onConstraintMet(WorkConstraintsTracker.java:150)
at androidx.work.impl.constraints.controllers.ConstraintController.updateCallback(ConstraintController.java:134)
at androidx.work.impl.constraints.controllers.ConstraintController.onConstraintChanged(ConstraintController.java:141)
at androidx.work.impl.constraints.trackers.ConstraintTracker.setState(ConstraintTracker.java:103)
at androidx.work.impl.constraints.trackers.NetworkStateTracker$NetworkStateBroadcastReceiver.onReceive(NetworkStateTracker.java:170)
at android.app.LoadedApk$ReceiverDispatcher$Args.run(LoadedApk.java:866)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5254)
at java.lang.reflect.Method.invoke(Method.java)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:902)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:697)
dc...@gmail.com <dc...@gmail.com> #12
Can you also turn on verbose logging in WorkManager while I am investigating this, so we can better understand what might be going on?
For that you need to custom initialize WorkManager.
Configuration configuration = new Configuration.Builder()
.setMinimumLoggingLevel(Log.DEBUG)
.build();
WorkManager.initialize(context, configuration);
Make sure you disable the default WorkManager initializer.
For that you need to custom initialize WorkManager.
Configuration configuration = new Configuration.Builder()
.setMinimumLoggingLevel(Log.DEBUG)
.build();
WorkManager.initialize(context, configuration);
Make sure you disable the default WorkManager initializer.
da...@gmail.com <da...@gmail.com> #13
I can but it won't make any difference. Crash log submission is voluntary in my app. User has to tap the notification, select send, open their email client and send the attachment. Since I cannot reproduce it in my test devices, I would need to push an update to the app logging enabled and hope that it crashes on someone that willing to send crash logs.
il...@google.com <il...@google.com> #14
Perhaps someone who are able to reproduce it can send them?
Description
This approach only seem to work on actions originating from the graph's start destination, and fails on actions between any other destinations. I created a sample project which reproduces the issue:
Here is the project's README detailing the issue:
# Bug in Android Navigation Component (alpha06)
(Note: I have only verified this in alpha06, I don't know if it exists in
previous versions)
## The problem
Basically the problem is that the NavOption "clearTask" was removed in
alpha02, and the recommended substitute was to use app:popUpTo pointing to
the root of the graph/the graph ID, together with app:popUpToInclusive="true".
However, this method does not work. It only seems to work for actions
going from the graph's start destination. If we have the following graph:
x y
A ---> B ---> C
Where A, B, and C are fragments, A is the start destination of the grapg,
and x, y are actions going from A to B and B to C respectively. Let's say
the graph's ID is "@+id/graph"
Then, if both actions x and y have
app:popUpTo="@+id/graph"
app:popUpToInclusive="true"
Then when navigating from A to B through x, and then hitting the back button
will exit the app (as expected). But if navigating from A to B to C through
x and y, and then hitting the back button we will navigate back to B — this
is not what was expected. The expected behavior with this graph is to always
exit the app when clicking the back button
## Environment
This was verified using:
Android Studio 3.2 RC 3
Build #AI-181.5540.7.32.4987877, built on August 31, 2018
JRE: 1.8.0_152-release-1136-b06 x86_64
JVM: OpenJDK 64-Bit Server VM by JetBrains s.r.o
macOS 10.13.6