Cache the list of notifications

app/src/main/java/app/insti/UpdatableList.java

@@ -4,25 +4,21 @@ import java.util.ArrayList;
 import java.util.List;
 
 public class UpdatableList<T> extends ArrayList<T> {
-    private List<T> cache = new ArrayList<>();
-
-    public List<T> getCache() {
-        return cache;
-    }
-
-    public void setCache(List<T> mCache) {
-        cache = mCache;
+    /** Convert a list to updatable list */
+    public void setList(List<T> list) {
+        this.clear();
+        this.addAll(list);
     }
 
     /** Update existing or add */
     public void updateCache(T t) {
-        for (int i = 0; i < cache.size(); i++) {
-            T cachedT = cache.get(i);
+        for (int i = 0; i < this.size(); i++) {
+            T cachedT = this.get(i);
             if (cachedT.equals(t)) {
-                cache.set(i, t);
+                this.set(i, t);
                 return;
             }
         }
-        cache.add(t);
+        this.add(t);
     }
 }

app/src/main/java/app/insti/Utils.java

@@ -18,6 +18,7 @@ import app.insti.activity.MainActivity;
 import app.insti.api.RetrofitInterface;
 import app.insti.api.model.Body;
 import app.insti.api.model.Event;
+import app.insti.api.model.Notification;
 import app.insti.api.model.User;
 import app.insti.fragment.BodyFragment;
 import app.insti.fragment.EventFragment;
@@ -25,6 +26,8 @@ import app.insti.fragment.UserFragment;
 
 public final class Utils {
     public static UpdatableList<Event> eventCache = new UpdatableList<>();
+    public static UpdatableList<Notification> notificationCache = null;
+
     private static String sessionId;
     private static RetrofitInterface retrofitInterface;
     public static Gson gson;

app/src/main/java/app/insti/activity/MainActivity.java

@@ -47,6 +47,7 @@ import java.util.List;
 import app.insti.Constants;
 import app.insti.R;
 import app.insti.SessionManager;
+import app.insti.UpdatableList;
 import app.insti.Utils;
 import app.insti.api.EmptyCallback;
 import app.insti.api.RetrofitInterface;
@@ -72,6 +73,7 @@ import app.insti.fragment.QuickLinksFragment;
 import app.insti.fragment.SettingsFragment;
 import app.insti.fragment.TrainingBlogFragment;
 import app.insti.fragment.UserFragment;
+import okhttp3.internal.Util;
 import retrofit2.Call;
 import retrofit2.Response;
 
@@ -95,8 +97,6 @@ public class MainActivity extends AppCompatActivity implements NavigationView.On
     private User currentUser;
     private BackHandledFragment selectedFragment;
     private Menu menu;
-    private RetrofitInterface retrofitInterface;
-    private List<Notification> notifications = null;
 
     /**
      * which menu item should be checked on activity start
@@ -186,7 +186,7 @@ public class MainActivity extends AppCompatActivity implements NavigationView.On
      */
     private void fetchNotifications() {
         // Try memory cache
-        if (notifications != null) {
+        if (Utils.notificationCache != null) {
             showNotifications();
             return;
         }
@@ -197,7 +197,8 @@ public class MainActivity extends AppCompatActivity implements NavigationView.On
             @Override
             public void onResponse(Call<List<Notification>> call, Response<List<Notification>> response) {
                 if (response.isSuccessful()) {
-                    notifications = response.body();
+                    Utils.notificationCache = new UpdatableList<>();
+                    Utils.notificationCache.setList(response.body());
                     showNotifications();
                 }
             }
@@ -208,7 +209,7 @@ public class MainActivity extends AppCompatActivity implements NavigationView.On
      * Show the right notification icon
      */
     private void showNotifications() {
-        if (notifications != null && !notifications.isEmpty()) {
+        if (Utils.notificationCache != null && !Utils.notificationCache.isEmpty()) {
             menu.findItem(R.id.action_notifications).setIcon(R.drawable.baseline_notifications_active_white_24);
         } else {
             menu.findItem(R.id.action_notifications).setIcon(R.drawable.ic_notifications_white_24dp);

app/src/main/java/app/insti/fragment/FeedFragment.java

@@ -17,6 +17,7 @@ import java.util.List;
 
 import app.insti.ActivityBuffer;
 import app.insti.R;
+import app.insti.UpdatableList;
 import app.insti.Utils;
 import app.insti.activity.MainActivity;
 import app.insti.adapter.FeedAdapter;
@@ -72,10 +73,10 @@ public class FeedFragment extends BaseFragment {
         fab = getView().findViewById(R.id.fab);
 
         // Initialize the feed
-        if (Utils.eventCache.getCache() == null || Utils.eventCache.getCache().size() == 0) {
+        if (Utils.eventCache == null || Utils.eventCache.isEmpty()) {
             updateFeed();
         } else {
-            displayEvents(Utils.eventCache.getCache());
+            displayEvents(Utils.eventCache);
         }
     }
 
@@ -105,8 +106,8 @@ public class FeedFragment extends BaseFragment {
             @Override
             public void onResponse(Call<NewsFeedResponse> call, Response<NewsFeedResponse> response) {
                 if (response.isSuccessful()) {
-                    Utils.eventCache.setCache(response.body().getEvents());
-                    displayEvents(Utils.eventCache.getCache());
+                    Utils.eventCache.setList(response.body().getEvents());
+                    displayEvents(Utils.eventCache);
                 }
                 //Server Error
                 feedSwipeRefreshLayout.setRefreshing(false);

app/src/main/java/app/insti/fragment/NotificationsFragment.java

@@ -14,10 +14,13 @@ import android.view.ViewGroup;
 import java.util.List;
 
 import app.insti.R;
+import app.insti.UpdatableList;
 import app.insti.Utils;
 import app.insti.adapter.NotificationsAdapter;
+import app.insti.api.EmptyCallback;
 import app.insti.api.RetrofitInterface;
 import app.insti.api.model.Notification;
+import okhttp3.internal.Util;
 import retrofit2.Call;
 import retrofit2.Callback;
 import retrofit2.Response;
@@ -28,8 +31,7 @@ import retrofit2.Response;
 public class NotificationsFragment extends BottomSheetDialogFragment {
 
     RecyclerView notificationsRecyclerView;
-
-    List<Notification> notifications;
+    NotificationsAdapter notificationsAdapter = null;
 
     public NotificationsFragment() {
         // Required empty public constructor
@@ -47,19 +49,23 @@ public class NotificationsFragment extends BottomSheetDialogFragment {
     public void onStart() {
         super.onStart();
 
+        /* Show cached notifications */
+        if (Utils.notificationCache != null) {
+            showNotifications(Utils.notificationCache);
+        } else {
+            Utils.notificationCache = new UpdatableList<>();
+        }
+
+        /* Update notifications */
         RetrofitInterface retrofitInterface = Utils.getRetrofitInterface();
-        retrofitInterface.getNotifications(Utils.getSessionIDHeader()).enqueue(new Callback<List<Notification>>() {
+        retrofitInterface.getNotifications(Utils.getSessionIDHeader()).enqueue(new EmptyCallback<List<Notification>>() {
             @Override
             public void onResponse(Call<List<Notification>> call, Response<List<Notification>> response) {
                 if (response.isSuccessful()) {
-                    notifications = response.body();
-                    showNotifications(notifications);
+                    Utils.notificationCache.setList(response.body());
+                    showNotifications(Utils.notificationCache);
                 }
             }
-
-            @Override
-            public void onFailure(Call<List<Notification>> call, Throwable t) {
-            }
         });
     }
 
@@ -70,9 +76,15 @@ public class NotificationsFragment extends BottomSheetDialogFragment {
         /* Hide loader */
         getView().findViewById(R.id.loadingPanel).setVisibility(View.GONE);
 
-        NotificationsAdapter notificationsAdapter = new NotificationsAdapter(notifications, this);
-        notificationsRecyclerView = (RecyclerView) getView().findViewById(R.id.notifications_recycler_view);
-        notificationsRecyclerView.setAdapter(notificationsAdapter);
-        notificationsRecyclerView.setLayoutManager(new LinearLayoutManager(getContext()));
+        /* Initialize */
+        if (notificationsAdapter == null) {
+            notificationsAdapter = new NotificationsAdapter(notifications, this);
+            notificationsRecyclerView = (RecyclerView) getView().findViewById(R.id.notifications_recycler_view);
+            notificationsRecyclerView.setAdapter(notificationsAdapter);
+            notificationsRecyclerView.setLayoutManager(new LinearLayoutManager(getContext()));
+        } else {
+            notificationsAdapter.setList(notifications);
+            notificationsAdapter.notifyDataSetChanged();
+        }
     }
 }