Show message if there are no updates

res/layout/activity_updates.xml

@@ -76,6 +76,21 @@
         </android.support.design.widget.CollapsingToolbarLayout>
     </android.support.design.widget.AppBarLayout>
 
+    <android.support.v4.widget.NestedScrollView
+        android:id="@+id/no_new_updates_view"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent"
+        android:padding="46dp"
+        app:layout_behavior="@string/appbar_scrolling_view_behavior">
+
+        <TextView
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content"
+            android:gravity="center"
+            android:text="@string/list_no_updates"
+            android:textColor="?android:textColorSecondary" />
+    </android.support.v4.widget.NestedScrollView>
+
     <android.support.v7.widget.RecyclerView
         android:id="@+id/recycler_view"
         android:layout_width="match_parent"

res/values/strings.xml

@@ -81,6 +81,7 @@
     <string name="list_download_progress_eta"><xliff:g id="filesize_without_unit" example="12.2">%1$s</xliff:g> of <xliff:g id="filesize_without_unit" example="310 MB">%2$s</xliff:g> - <xliff:g id="duration" example="3 minutes">%3$s</xliff:g> left</string>
     <string name="list_installing_update">Installing update</string>
     <string name="list_verifying_update">Verifying update</string>
+    <string name="list_no_updates">No new updates found. To manually check for new updates, use the Refresh button.</string>
 
     <string name="action_description_download">Download</string>
     <string name="action_description_pause">Pause download</string>

src/org/lineageos/updater/UpdatesActivity.java

@@ -40,6 +40,7 @@ import android.support.v7.widget.Toolbar;
 import android.util.Log;
 import android.view.Menu;
 import android.view.MenuItem;
+import android.view.View;
 import android.widget.TextView;
 
 import org.json.JSONException;
@@ -285,17 +286,24 @@ public class UpdatesActivity extends UpdatesListActivity {
 
         List<String> updateIds = new ArrayList<>();
         List<UpdateInfo> sortedUpdates = controller.getUpdates();
-        Collections.sort(sortedUpdates, new Comparator<UpdateInfo>() {
-            @Override
-            public int compare(UpdateInfo u1, UpdateInfo u2) {
-                return Long.compare(u2.getTimestamp(), u1.getTimestamp());
+        if (sortedUpdates.isEmpty()) {
+            findViewById(R.id.no_new_updates_view).setVisibility(View.VISIBLE);
+            findViewById(R.id.recycler_view).setVisibility(View.GONE);
+        } else {
+            findViewById(R.id.no_new_updates_view).setVisibility(View.GONE);
+            findViewById(R.id.recycler_view).setVisibility(View.VISIBLE);
+            Collections.sort(sortedUpdates, new Comparator<UpdateInfo>() {
+                @Override
+                public int compare(UpdateInfo u1, UpdateInfo u2) {
+                    return Long.compare(u2.getTimestamp(), u1.getTimestamp());
+                }
+            });
+            for (UpdateInfo update : sortedUpdates) {
+                updateIds.add(update.getDownloadId());
             }
-        });
-        for (UpdateInfo update : sortedUpdates) {
-            updateIds.add(update.getDownloadId());
+            mAdapter.setData(updateIds);
+            mAdapter.notifyDataSetChanged();
         }
-        mAdapter.setData(updateIds);
-        mAdapter.notifyDataSetChanged();
     }
 
     private void getUpdatesList() {