'new comic' was still displayed after viewing a comic from a notification, lead to crash

[not-inept]

Steps to reproduce the crash:

1. Click on comic notification from my notifications pane
2. View new comic
3. Go back to list view
4. Notice that the comic I just viewed is still marked as unread
5. View it again and go back to list view
6. Notice it is now marked as read, but there is still a ribbon at the bottom indicating there is a new comic
7. Click the ribbon- this caused the crash

There seem to be two or three bugs:

1. Viewing comics from the notification doesn't mark them as read
2. The notification ribbon shows up after the new comic has been read
3. The notification ribbon causes a crash when there are no new comics

java.lang.NullPointerException: Attempt to write to field 'int de.tap.easy_xkcd.Activities.MainActivity.lastComicNumber' on a null object reference
at de.tap.easy_xkcd.fragments.comics.ComicFragment.pageSelected(ComicFragment.java:726)
at de.tap.easy_xkcd.fragments.comics.OfflineFragment.pageSelected(OfflineFragment.java:107)
at de.tap.easy_xkcd.fragments.comics.OfflineFragment$1.onPageSelected(OfflineFragment.java:95)
at androidx.viewpager.widget.ViewPager.dispatchOnPageSelected(ViewPager.java:1947)
at androidx.viewpager.widget.ViewPager.scrollToItem(ViewPager.java:690)
at androidx.viewpager.widget.ViewPager.setCurrentItemInternal(ViewPager.java:670)
at androidx.viewpager.widget.ViewPager.setCurrentItemInternal(ViewPager.java:631)
at androidx.viewpager.widget.ViewPager.setCurrentItem(ViewPager.java:623)
at de.tap.easy_xkcd.fragments.comics.ComicFragment.getLatestComic(ComicFragment.java:665)
at de.tap.easy_xkcd.fragments.comics.OfflineFragment$2.onClick(OfflineFragment.java:167)
at com.google.android.material.snackbar.Snackbar$1.onClick(Snackbar.java:317)
at android.view.View.performClick(View.java:7339)
at android.widget.TextView.performClick(TextView.java:14177)
at android.view.View.performClickInternal(View.java:7305)
at android.view.View.access$3200(View.java:846)
at android.view.View$PerformClick.run(View.java:27788)
at android.os.Handler.handleCallback(Handler.java:873)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:214)
at android.app.ActivityThread.main(ActivityThread.java:7045)
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:964)