fix crash in NotificationsFragment (#1119)

* fix crash in NotificationsFragment

* don't reload notifications

* add updateAdapter()

app/src/main/java/com/keylesspalace/tusky/TabPreferenceActivity.kt

@@ -47,6 +47,8 @@ class TabPreferenceActivity : BaseActivity(), Injectable, ItemInteractionListene
     private lateinit var touchHelper: ItemTouchHelper
     private lateinit var addTabAdapter: TabAdapter
 
+    private var tabsChanged = false
+
     private val selectedItemElevation by lazy { resources.getDimension(R.dimen.selected_drag_item_elevation) }
 
     override fun onCreate(savedInstanceState: Bundle?) {
@@ -188,6 +190,7 @@ class TabPreferenceActivity : BaseActivity(), Injectable, ItemInteractionListene
                     .subscribe()
 
         }
+        tabsChanged = true
     }
 
     override fun onBackPressed() {
@@ -208,7 +211,9 @@ class TabPreferenceActivity : BaseActivity(), Injectable, ItemInteractionListene
 
     override fun onPause() {
         super.onPause()
-        eventHub.dispatch(MainTabsChangedEvent(currentTabs))
+        if(tabsChanged) {
+            eventHub.dispatch(MainTabsChangedEvent(currentTabs))
+        }
     }
 
     companion object {

app/src/main/java/com/keylesspalace/tusky/fragment/NotificationsFragment.java

@@ -207,14 +207,19 @@ public class NotificationsFragment extends SFragment implements
         adapter.setUseAbsoluteTime(useAbsoluteTime);
         recyclerView.setAdapter(adapter);
 
-        notifications.clear();
         topLoading = false;
         bottomLoading = false;
         bottomId = null;
 
-        ((SimpleItemAnimator) recyclerView.getItemAnimator()).setSupportsChangeAnimations(false);
+        updateAdapter();
+
+        if (notifications.isEmpty()) {
+            sendFetchNotificationsRequest(null, null, FetchEnd.BOTTOM, -1);
+        } else {
+            progressBar.setVisibility(View.GONE);
+        }
 
-        sendFetchNotificationsRequest(null, null, FetchEnd.BOTTOM, -1);
+        ((SimpleItemAnimator) recyclerView.getItemAnimator()).setSupportsChangeAnimations(false);
 
         return rootView;
     }