Never wrap RecyclerView with a NestedScrollView

Wrapping a ``RecyclerView`` with a ``NestedScrollView`` breaks its recycling
functionality because the view height is stretched to fit the full list
of entries.

We never noticed performance issues in these two cases because these
lists never get very long. Let's fix these cases anyway so that we
don't accidentally base a new use of a ``RecyclerView`` on this broken
pattern.

Also renamed ``list_slots`` to ``list_groups``. Must have been
a copy-paste error.

app/src/main/java/com/beemdevelopment/aegis/ui/GroupManagerActivity.java

@@ -24,7 +24,7 @@
 public class GroupManagerActivity extends AegisActivity implements GroupAdapter.Listener {
     private GroupAdapter _adapter;
     private HashSet<String> _removedGroups;
-    private RecyclerView _slotsView;
+    private RecyclerView _groupsView;
     private View _emptyStateView;
     private BackPressHandler _backPressHandler;
 
@@ -51,11 +51,11 @@ protected void onCreate(Bundle savedInstanceState) {
         }
 
         _adapter = new GroupAdapter(this);
-        _slotsView= findViewById(R.id.list_slots);
+        _groupsView = findViewById(R.id.list_groups);
         LinearLayoutManager layoutManager = new LinearLayoutManager(this);
-        _slotsView.setLayoutManager(layoutManager);
-        _slotsView.setAdapter(_adapter);
-        _slotsView.setNestedScrollingEnabled(false);
+        _groupsView.setLayoutManager(layoutManager);
+        _groupsView.setAdapter(_adapter);
+        _groupsView.setNestedScrollingEnabled(false);
 
         for (String group : _vaultManager.getVault().getGroups()) {
             _adapter.addGroup(group);
@@ -135,10 +135,10 @@ public boolean onOptionsItemSelected(MenuItem item) {
 
     private void updateEmptyState() {
         if (_adapter.getItemCount() > 0) {
-            _slotsView.setVisibility(View.VISIBLE);
+            _groupsView.setVisibility(View.VISIBLE);
             _emptyStateView.setVisibility(View.GONE);
         } else {
-            _slotsView.setVisibility(View.GONE);
+            _groupsView.setVisibility(View.GONE);
             _emptyStateView.setVisibility(View.VISIBLE);
         }
     }

app/src/main/java/com/beemdevelopment/aegis/ui/fragments/preferences/IconPacksManagerFragment.java

@@ -44,7 +44,6 @@ public class IconPacksManagerFragment extends Fragment implements IconPackAdapte
     @Inject
     VaultManager _vaultManager;
 
-    private View _iconPacksView;
     private RecyclerView _iconPacksRecyclerView;
     private IconPackAdapter _adapter;
     private LinearLayout _noIconPacksView;
@@ -62,7 +61,6 @@ public void onViewCreated(@NonNull View view, Bundle savedInstanceState) {
 
         _noIconPacksView = view.findViewById(R.id.vEmptyList);
         ((TextView) view.findViewById(R.id.txt_no_icon_packs)).setMovementMethod(LinkMovementMethod.getInstance());
-        _iconPacksView = view.findViewById(R.id.view_icon_packs);
         _adapter = new IconPackAdapter(this);
         _iconPacksRecyclerView = view.findViewById(R.id.list_icon_packs);
         LinearLayoutManager layoutManager = new LinearLayoutManager(requireContext());
@@ -169,10 +167,10 @@ private void startImportIconPack() {
 
     private void updateEmptyState() {
         if (_adapter.getItemCount() > 0) {
-            _iconPacksView.setVisibility(View.VISIBLE);
+            _iconPacksRecyclerView.setVisibility(View.VISIBLE);
             _noIconPacksView.setVisibility(View.GONE);
         } else {
-            _iconPacksView.setVisibility(View.GONE);
+            _iconPacksRecyclerView.setVisibility(View.GONE);
             _noIconPacksView.setVisibility(View.VISIBLE);
         }
     }

app/src/main/res/layout/activity_groups.xml

@@ -18,23 +18,11 @@
             android:background="?attr/colorAppBar" />
     </com.google.android.material.appbar.AppBarLayout>
 
-    <androidx.core.widget.NestedScrollView
-        android:layout_width="match_parent"
+    <androidx.recyclerview.widget.RecyclerView
+        android:id="@+id/list_groups"
         android:layout_height="match_parent"
-        app:layout_behavior="com.google.android.material.appbar.AppBarLayout$ScrollingViewBehavior">
-
-        <LinearLayout
-            android:layout_width="match_parent"
-            android:layout_height="wrap_content"
-            android:orientation="vertical">
-
-            <androidx.recyclerview.widget.RecyclerView
-                android:id="@+id/list_slots"
-                android:layout_width="match_parent"
-                android:layout_height="wrap_content"
-                android:scrollbars="vertical"/>
-        </LinearLayout>
-    </androidx.core.widget.NestedScrollView>
+        android:layout_width="match_parent"
+        app:layout_behavior="com.google.android.material.appbar.AppBarLayout$ScrollingViewBehavior" />
 
     <LinearLayout
         android:layout_width="match_parent"

app/src/main/res/layout/fragment_icon_packs.xml

@@ -47,26 +47,11 @@
 
     </LinearLayout>
 
-    <androidx.core.widget.NestedScrollView
-        android:id="@+id/view_icon_packs"
+    <androidx.recyclerview.widget.RecyclerView
+        android:id="@+id/list_icon_packs"
         android:layout_width="match_parent"
         android:layout_height="match_parent"
-        app:layout_behavior="com.google.android.material.appbar.AppBarLayout$ScrollingViewBehavior">
-
-        <LinearLayout
-            android:layout_width="match_parent"
-            android:layout_height="wrap_content"
-            android:orientation="vertical">
-
-            <androidx.recyclerview.widget.RecyclerView
-                android:id="@+id/list_icon_packs"
-                android:layout_width="match_parent"
-                android:layout_height="wrap_content"
-                android:scrollbars="vertical"/>
-
-        </LinearLayout>
-
-    </androidx.core.widget.NestedScrollView>
+        app:layout_behavior="com.google.android.material.appbar.AppBarLayout$ScrollingViewBehavior" />
 
     <com.google.android.material.floatingactionbutton.FloatingActionButton
         android:id="@+id/fab"