Refactored all the other classes to support multi user. Clearing the app data is required before launching the app.

app/src/main/java/SubredditDatabase/SubredditData.java

@@ -1,29 +1,49 @@
 package SubredditDatabase;
 
+import androidx.annotation.NonNull;
 import androidx.room.ColumnInfo;
 import androidx.room.Entity;
-import androidx.annotation.NonNull;
-
-import SubscribedSubredditDatabase.SubscribedSubredditData;
+import androidx.room.PrimaryKey;
 
 @Entity(tableName = "subreddits")
-public class SubredditData extends SubscribedSubredditData {
+public class SubredditData {
+    @PrimaryKey
+    @NonNull
+    @ColumnInfo(name = "id")
+    private String id;
+    @ColumnInfo(name = "name")
+    private String name;
+    @ColumnInfo(name = "icon")
+    private String iconUrl;
     @ColumnInfo(name = "banner")
     private String bannerUrl;
-
     @ColumnInfo(name = "description")
     private String description;
-
     @ColumnInfo(name = "subscribers_count")
     private int nSubscribers;
 
     public SubredditData(@NonNull String id, String name, String iconUrl, String bannerUrl, String description, int nSubscribers) {
-        super(id, name, iconUrl);
+        this.id = id;
+        this.name = name;
+        this.iconUrl = iconUrl;
         this.bannerUrl = bannerUrl;
         this.description = description;
         this.nSubscribers = nSubscribers;
     }
 
+    @NonNull
+    public String getId() {
+        return id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public String getIconUrl() {
+        return iconUrl;
+    }
+
     public String getBannerUrl() {
         return bannerUrl;
     }

app/src/main/java/SubredditDatabase/SubredditRepository.java

@@ -1,17 +1,17 @@
 package SubredditDatabase;
 
-import android.app.Application;
-import androidx.lifecycle.LiveData;
 import android.os.AsyncTask;
 
+import androidx.lifecycle.LiveData;
+
+import ml.docilealligator.infinityforreddit.RedditDataRoomDatabase;
+
 public class SubredditRepository {
     private SubredditDao mSubredditDao;
     private LiveData<SubredditData> mSubredditLiveData;
 
-    SubredditRepository(Application application, String subredditName) {
-        SubredditRoomDatabase db = SubredditRoomDatabase.getDatabase(application);
-        mSubredditDao = db.subredditDao();
-
+    SubredditRepository(RedditDataRoomDatabase redditDataRoomDatabase, String subredditName) {
+        mSubredditDao = redditDataRoomDatabase.subredditDao();
         mSubredditLiveData = mSubredditDao.getSubredditLiveDataByName(subredditName);
     }
 

app/src/main/java/SubredditDatabase/SubredditRoomDatabase.java

@@ -1,26 +0,0 @@
-package SubredditDatabase;
-
-import androidx.room.Database;
-import androidx.room.Room;
-import androidx.room.RoomDatabase;
-import android.content.Context;
-
-@Database(entities = {SubredditData.class}, version = 1)
-public abstract class SubredditRoomDatabase extends RoomDatabase{
-    private static SubredditRoomDatabase INSTANCE;
-
-    public abstract SubredditDao subredditDao();
-
-    public static SubredditRoomDatabase getDatabase(final Context context) {
-        if(INSTANCE == null) {
-            synchronized (SubredditRoomDatabase.class) {
-                if(INSTANCE == null) {
-                    INSTANCE = Room.databaseBuilder(context.getApplicationContext(),
-                            SubredditRoomDatabase.class, "subreddits")
-                            .build();
-                }
-            }
-        }
-        return INSTANCE;
-    }
-}

app/src/main/java/SubredditDatabase/SubredditViewModel.java

@@ -7,13 +7,15 @@ import androidx.lifecycle.ViewModel;
 import androidx.lifecycle.ViewModelProvider;
 import androidx.annotation.NonNull;
 
+import ml.docilealligator.infinityforreddit.RedditDataRoomDatabase;
+
 public class SubredditViewModel extends AndroidViewModel {
     private SubredditRepository mSubredditRepository;
     private LiveData<SubredditData> mSubredditLiveData;
 
-    public SubredditViewModel(Application application, String id) {
+    public SubredditViewModel(Application application, RedditDataRoomDatabase redditDataRoomDatabase, String id) {
         super(application);
-        mSubredditRepository = new SubredditRepository(application, id);
+        mSubredditRepository = new SubredditRepository(redditDataRoomDatabase, id);
         mSubredditLiveData = mSubredditRepository.getSubredditLiveData();
     }
 
@@ -29,19 +31,20 @@ public class SubredditViewModel extends AndroidViewModel {
 
         @NonNull
         private final Application mApplication;
+        private final RedditDataRoomDatabase mRedditDataRoomDatabase;
+        private final String mSubredditName;
 
-        private final String subredditName;
-
-        public Factory(@NonNull Application application, String subredditName) {
+        public Factory(@NonNull Application application, RedditDataRoomDatabase redditDataRoomDatabase, String subredditname) {
             mApplication = application;
-            this.subredditName = subredditName;
+            mRedditDataRoomDatabase = redditDataRoomDatabase;
+            mSubredditName = subredditname;
         }
 
         @NonNull
         @Override
         public <T extends ViewModel> T create(@NonNull Class<T> modelClass) {
             //noinspection unchecked
-            return (T) new SubredditViewModel(mApplication, subredditName);
+            return (T) new SubredditViewModel(mApplication, mRedditDataRoomDatabase, mSubredditName);
         }
     }
 }