Minor changes

app/src/main/java/eu/kanade/mangafeed/event/LibraryMangasEvent.java

@@ -1,8 +1,11 @@
 package eu.kanade.mangafeed.event;
 
+import android.support.annotation.Nullable;
+
 import java.util.List;
 import java.util.Map;
 
+import eu.kanade.mangafeed.data.database.models.Category;
 import eu.kanade.mangafeed.data.database.models.Manga;
 
 public class LibraryMangasEvent {
@@ -16,4 +19,9 @@ public class LibraryMangasEvent {
     public Map<Integer, List<Manga>> getMangas() {
         return mangas;
     }
+
+    @Nullable
+    public List<Manga> getMangasForCategory(Category category) {
+        return mangas.get(category.id);
+    }
 }

app/src/main/java/eu/kanade/mangafeed/ui/library/LibraryAdapter.java

@@ -42,8 +42,4 @@ public class LibraryAdapter extends SmartFragmentStatePagerAdapter {
         }
     }
 
-    public boolean hasDefaultCategory() {
-        return categories.get(0).id == 0;
-    }
-
 }

app/src/main/java/eu/kanade/mangafeed/ui/library/LibraryCategoryFragment.java

@@ -108,7 +108,7 @@ public class LibraryCategoryFragment extends BaseFragment
             return;
 
         Category category = categories.get(position);
-        List<Manga> mangas = event.getMangas().get(category.id);
+        List<Manga> mangas = event.getMangasForCategory(category);
         if (mangas == null) {
             mangas = new ArrayList<>();
         }

app/src/main/java/eu/kanade/mangafeed/ui/library/LibraryFragment.java

@@ -7,7 +7,6 @@ import android.support.design.widget.AppBarLayout;
 import android.support.design.widget.TabLayout;
 import android.support.v4.view.ViewPager;
 import android.support.v7.view.ActionMode;
-import android.util.Pair;
 import android.view.LayoutInflater;
 import android.view.Menu;
 import android.view.MenuInflater;
@@ -119,26 +118,20 @@ public class LibraryFragment extends BaseRxFragment<LibraryPresenter>
         startActivity(intent);
     }
 
-    public void onNextLibraryUpdate(Pair<List<Category>, Map<Integer, List<Manga>>> pair) {
-        boolean mangasInDefaultCategory = pair.second.get(0) != null;
-        boolean initialized = adapter.categories != null;
+    public void onNextLibraryUpdate(List<Category> categories, Map<Integer, List<Manga>> mangas) {
+        boolean hasMangasInDefaultCategory = mangas.get(0) != null;
+        int activeCat = adapter.categories != null ? viewPager.getCurrentItem() : activeCategory;
 
-        // If there are mangas in the default category and the adapter doesn't have it,
-        // create the default category
-        if (mangasInDefaultCategory && (!initialized || !adapter.hasDefaultCategory())) {
-            setCategoriesWithDefault(pair.first);
-        }
-        // If there aren't mangas in the default category and the adapter have it,
-        // remove the default category
-        else if (!mangasInDefaultCategory && (!initialized || adapter.hasDefaultCategory())) {
-            setCategories(pair.first);
+        if (hasMangasInDefaultCategory) {
+            setCategoriesWithDefault(categories);
+        } else {
+            setCategories(categories);
         }
         // Restore active category
-        if (!initialized) {
-            viewPager.setCurrentItem(activeCategory, false);
-        }
+        viewPager.setCurrentItem(activeCat, false);
+
         // Send the mangas to child fragments after the adapter is updated
-        EventBus.getDefault().postSticky(new LibraryMangasEvent(pair.second));
+        EventBus.getDefault().postSticky(new LibraryMangasEvent(mangas));
     }
 
     private void setCategoriesWithDefault(List<Category> categories) {

app/src/main/java/eu/kanade/mangafeed/ui/library/LibraryPresenter.java

@@ -42,7 +42,7 @@ public class LibraryPresenter extends BasePresenter<LibraryFragment> {
 
         restartableLatestCache(GET_LIBRARY,
                 this::getLibraryObservable,
-                LibraryFragment::onNextLibraryUpdate);
+                (view, pair) -> view.onNextLibraryUpdate(pair.first, pair.second));
 
         start(GET_LIBRARY);
     }