Some fixes with cache and notifications

app/src/main/java/app/fedilab/android/client/entities/api/Notification.java

@@ -14,6 +14,8 @@ package app.fedilab.android.client.entities.api;
  * You should have received a copy of the GNU General Public License along with Fedilab; if not,
  * see <http://www.gnu.org/licenses>. */
 
+import androidx.annotation.Nullable;
+
 import com.google.gson.Gson;
 import com.google.gson.annotations.SerializedName;
 import com.google.gson.reflect.TypeToken;
@@ -45,6 +47,15 @@ public class Notification {
         BOTTOM
     }
 
+    @Override
+    public boolean equals(@Nullable Object obj) {
+        boolean same = false;
+        if (obj instanceof Notification) {
+            same = this.id.equals(((Notification) obj).id);
+        }
+        return same;
+    }
+
     public transient List<Notification> relatedNotifications;
     public boolean isFetchMore;
     public boolean isFetchMoreHidden = false;

app/src/main/java/app/fedilab/android/ui/fragment/timeline/FragmentMastodonNotification.java

@@ -508,8 +508,10 @@ public class FragmentMastodonNotification extends Fragment implements Notificati
                         //We compare the date of each status and we only add status having a date greater than the another, it is inserted at this position
                         //Pinned messages are ignored because their date can be older
                         if (notificationReceived.id.compareTo(notificationsAlreadyPresent.id) > 0) {
+                            if (!notificationList.contains(notificationReceived)) {
                                 notificationList.add(position, notificationReceived);
                                 notificationAdapter.notifyItemInserted(position);
+                            }
                             break;
                         }
                         position++;