FCM Data message is not navigating to desired fragment when app is in background

问题

I have an app with a somewhat complex flow. There is a launcher activity (SplashActivity), then a MainActivity, which has five fragments, then in the fifth fragment, there is the DesiredActivity which has three fragments, one of them being the DesiredFragment. When the app is in foreground and we click on the push notification (data message type), the DesiredFragment opens, no issues there, but when the app is in background, the MainActivity opens, instead of the DesiredFragment, on click of the push notification.

Also, when in debug mode, the DesiredFragment opens without any issues, when the app is in background. The issue arises in normal run and not in debug mode (According to my research, this generally happens in case of race conditions, but there are no threads, async tasks, etc involved in my code.

Can anyone help me with what am I doing wrong?

This is the manifest file entry for DesiredActivity:

<activity 
        android:name=".activities.DesiredActivity"
        android:parentActivityName=".activities.MainActivity"
        android:exported="true">
        <meta-data
            android:name="android.support.PARENT_ACTIVITY"
            android:value=".activities.MainActivity" />
</activity>

This is the code for onMessageRecieved in FirebaseMessagingServices. (There is no issue with NotificationBuilder aand NotificationManager)

        Intent intent = new Intent(this, Appointments.class);
        backIntent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK);
        intent.putExtra("comingFromPushFragOpen","RequestedAppointment");


        TaskStackBuilder stackBuilder = TaskStackBuilder.create(this);
        stackBuilder.addParentStack(Appointments.class);
        stackBuilder.addNextIntent(intent);

        PendingIntent contentIntent = stackBuilder.getPendingIntent(3,PendingIntent.FLAG_ONE_SHOT); 

        mBuilder.setContentIntent(contentIntent);
        notificationManager.notify(3, mBuilder.build());

Code in onCreate of DesiredActivity, we use a viewpager to load the DesiredFragment here:

 if (getIntent().hasExtra("comingFromPushFragOpen") && getIntent().getStringExtra("comingFromPushFragOpen").equalsIgnoreCase("RequestedAppointment"))
        appointmentsViewpager.setCurrentItem(1);

Again, the push notification is navigating to the DesiredFragment without any issue when the app is in foreground, the issue arises wheh the app is in background, it may have to do something with the way I am handling the intent and the pendingintent.

Any help would be appreciated.

来源：https://stackoverflow.com/questions/62446449/fcm-data-message-is-not-navigating-to-desired-fragment-when-app-is-in-background