some changes

app/src/main/AndroidManifest.xml

@@ -24,7 +24,7 @@
     </queries>
     <application
         android:name="app.fedilab.android.MainApplication"
-        android:allowBackup="false"
+        android:allowBackup="true"
         android:dataExtractionRules="@xml/extraction_rules"
         android:fullBackupContent="@xml/backup_rules"
         android:configChanges="orientation|screenSize"

app/src/main/java/app/fedilab/android/BaseMainActivity.java

@@ -243,7 +243,7 @@ public abstract class BaseMainActivity extends BaseActivity implements NetworkSt
             if (b != null) {
                 if (b.getBoolean(Helper.RECEIVE_REDRAW_TOPBAR, false)) {
                     List<MastodonList> mastodonLists = (List<MastodonList>) b.getSerializable(Helper.RECEIVE_MASTODON_LIST);
-                    if (mastodonLists.size() == 0) {
+                    if (mastodonLists != null && mastodonLists.size() == 0) {
                         mastodonLists = null;
                     }
                     redrawPinned(mastodonLists);
@@ -1228,9 +1228,9 @@ public abstract class BaseMainActivity extends BaseActivity implements NetworkSt
                             //Fetch remote lists for the authenticated account and update them
                             new ViewModelProvider(BaseMainActivity.this).get(TimelinesVM.class).getLists(currentInstance, currentToken)
                                     .observe(this, mastodonLists -> {
-                                                if (mastodonLists.size() == 0) {
-                                                    mastodonLists = null;
-                                                }
+                                        if (mastodonLists != null && mastodonLists.size() == 0) {
+                                            mastodonLists = null;
+                                        }
                                                 PinnedTimelineHelper.redrawTopBarPinned(BaseMainActivity.this, binding, pinned, bottomMenu, mastodonLists);
                                             }
                                     );