Force close when trying to save list state in StoryFragment

[bishopmatthew]

I seem to have introduced this when I added saving the list position to SharedPreferences. By the way, we have to save the list position to SharedPreferences (instead of a to a bundle) because StoryFragment is actually finished when we switch to the comments page. In the next version we should switch it so that (almost) everything is a fragment and thus we won't have the same issues with a circular back stack.

Stack trace:

FATAL EXCEPTION
java.lang.RuntimeException: Unable to pause activity {com.airlocksoftware.hackernews/com.airlocksoftware.hackernews.activity.MainActivity}: java.lang.NullPointerException
       at android.app.ActivityThread.performPauseActivity(ActivityThread.java:2916)
       at android.app.ActivityThread.performPauseActivity(ActivityThread.java:2872)
       at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:3559)
       at android.app.ActivityThread.access$800(ActivityThread.java:140)
       at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1244)
       at android.os.Handler.dispatchMessage(Handler.java:99)
       at android.os.Looper.loop(Looper.java:137)
       at android.app.ActivityThread.main(ActivityThread.java:4947)
       at java.lang.reflect.Method.invokeNative(Method.java)
       at java.lang.reflect.Method.invoke(Method.java:511)
       at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1038)
       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:805)
       at dalvik.system.NativeStart.main(NativeStart.java)
Caused by: java.lang.NullPointerException
       at com.airlocksoftware.hackernews.fragment.StoryFragment.onPause(StoryFragment.java:161)
       at android.support.v4.app.Fragment.performPause(Fragment.java:1661)
       at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:973)
       at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1104)
       at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1086)
       at android.support.v4.app.FragmentManagerImpl.dispatchPause(FragmentManager.java:1898)
       at android.support.v4.app.FragmentActivity.onPause(FragmentActivity.java:412)
       at android.app.Activity.performPause(Activity.java:5305)
       at android.app.Instrumentation.callActivityOnPause(Instrumentation.java:1240)
       at android.app.ActivityThread.performPauseActivity(ActivityThread.java:2903)
       at android.app.ActivityThread.performPauseActivity(ActivityThread.java:2872)
       at android.app.ActivityThread.handleRelaunchActivity(ActivityThread.java:3559)
       at android.app.ActivityThread.access$800(ActivityThread.java:140)
       at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1244)
       at android.os.Handler.dispatchMessage(Handler.java:99)
       at android.os.Looper.loop(Looper.java:137)
       at android.app.ActivityThread.main(ActivityThread.java:4947)
       at java.lang.reflect.Method.invokeNative(Method.java)
       at java.lang.reflect.Method.invoke(Method.java:511)
       at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1038)
       at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:805)
       at dalvik.system.NativeStart.main(NativeStart.java)

[pkillian]

Should release V2 and mark issue as closed on Crashlytics and verify it no longer pops up in any later versions of the app after this commit.

[pkillian]

Seems like version 2.1.3 is free of this bug; I'll keep an eye on Crashlytics for another day or two to make sure before closing this for good.