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

app/src/main/java/SubscribedUserDatabase/SubscribedUserDao.java

@@ -16,12 +16,12 @@ public interface SubscribedUserDao {
     @Query("DELETE FROM subscribed_users")
     void deleteAllSubscribedUsers();
 
-    @Query("SELECT * FROM subscribed_users ORDER BY name COLLATE NOCASE ASC")
-    LiveData<List<SubscribedUserData>> getAllSubscribedUsers();
+    @Query("SELECT * FROM subscribed_users WHERE username = :accountName ORDER BY name COLLATE NOCASE ASC")
+    LiveData<List<SubscribedUserData>> getAllSubscribedUsers(String accountName);
 
-    @Query("SELECT * FROM subscribed_users WHERE name = :userName COLLATE NOCASE LIMIT 1")
-    SubscribedUserData getSubscribedUser(String userName);
+    @Query("SELECT * FROM subscribed_users WHERE name = :name AND username = :accountName COLLATE NOCASE LIMIT 1")
+    SubscribedUserData getSubscribedUser(String name, String accountName);
 
-    @Query("DELETE FROM subscribed_users WHERE name = :userName")
-    void deleteSubscribedUser(String userName);
+    @Query("DELETE FROM subscribed_users WHERE name = :name AND username = :accountName")
+    void deleteSubscribedUser(String name, String accountName);
 }

app/src/main/java/SubscribedUserDatabase/SubscribedUserData.java

@@ -1,11 +1,15 @@
 package SubscribedUserDatabase;
 
+import androidx.annotation.NonNull;
 import androidx.room.ColumnInfo;
 import androidx.room.Entity;
+import androidx.room.ForeignKey;
 import androidx.room.PrimaryKey;
-import androidx.annotation.NonNull;
 
-@Entity(tableName = "subscribed_users")
+import Account.Account;
+
+@Entity(tableName = "subscribed_users", foreignKeys = @ForeignKey(entity = Account.class, parentColumns = "username",
+        childColumns = "username", onDelete = ForeignKey.CASCADE))
 public class SubscribedUserData {
     @PrimaryKey
     @NonNull
@@ -13,10 +17,13 @@ public class SubscribedUserData {
     private String name;
     @ColumnInfo(name = "icon")
     private String iconUrl;
+    @ColumnInfo(name = "username")
+    private String username;
 
-    public SubscribedUserData(@NonNull String name, String iconUrl) {
+    public SubscribedUserData(@NonNull String name, String iconUrl, String username) {
         this.name = name;
         this.iconUrl = iconUrl;
+        this.username = username;
     }
 
     @NonNull
@@ -27,4 +34,12 @@ public class SubscribedUserData {
     public String getIconUrl() {
         return iconUrl;
     }
+
+    public void setUsername(String username) {
+        this.username = username;
+    }
+
+    public String getUsername() {
+        return username;
+    }
 }

app/src/main/java/SubscribedUserDatabase/SubscribedUserRepository.java

@@ -1,19 +1,20 @@
 package SubscribedUserDatabase;
 
-import android.app.Application;
-import androidx.lifecycle.LiveData;
 import android.os.AsyncTask;
 
+import androidx.lifecycle.LiveData;
+
 import java.util.List;
 
+import ml.docilealligator.infinityforreddit.RedditDataRoomDatabase;
+
 public class SubscribedUserRepository {
     private SubscribedUserDao mSubscribedUserDao;
     private LiveData<List<SubscribedUserData>> mAllSubscribedUsers;
 
-    SubscribedUserRepository(Application application) {
-        SubscribedUserRoomDatabase db = SubscribedUserRoomDatabase.getDatabase(application);
-        mSubscribedUserDao = db.subscribedUserDao();
-        mAllSubscribedUsers = mSubscribedUserDao.getAllSubscribedUsers();
+    SubscribedUserRepository(RedditDataRoomDatabase redditDataRoomDatabase, String accountName) {
+        mSubscribedUserDao = redditDataRoomDatabase.subscribedUserDao();
+        mAllSubscribedUsers = mSubscribedUserDao.getAllSubscribedUsers(accountName);
     }
 
     LiveData<List<SubscribedUserData>> getAllSubscribedSubreddits() {

app/src/main/java/SubscribedUserDatabase/SubscribedUserRoomDatabase.java

@@ -1,26 +0,0 @@
-package SubscribedUserDatabase;
-
-import androidx.room.Database;
-import androidx.room.Room;
-import androidx.room.RoomDatabase;
-import android.content.Context;
-
-@Database(entities = {SubscribedUserData.class}, version = 1)
-public abstract class SubscribedUserRoomDatabase extends RoomDatabase {
-    private static SubscribedUserRoomDatabase INSTANCE;
-
-    public abstract SubscribedUserDao subscribedUserDao();
-
-    public static SubscribedUserRoomDatabase getDatabase(final Context context) {
-        if(INSTANCE == null) {
-            synchronized (SubscribedUserRoomDatabase.class) {
-                if(INSTANCE == null) {
-                    INSTANCE = Room.databaseBuilder(context.getApplicationContext(),
-                            SubscribedUserRoomDatabase.class, "subscribed_users")
-                            .build();
-                }
-            }
-        }
-        return INSTANCE;
-    }
-}

app/src/main/java/SubscribedUserDatabase/SubscribedUserViewModel.java

@@ -1,18 +1,24 @@
 package SubscribedUserDatabase;
 
 import android.app.Application;
+
+import androidx.annotation.NonNull;
 import androidx.lifecycle.AndroidViewModel;
 import androidx.lifecycle.LiveData;
+import androidx.lifecycle.ViewModel;
+import androidx.lifecycle.ViewModelProvider;
 
 import java.util.List;
 
+import ml.docilealligator.infinityforreddit.RedditDataRoomDatabase;
+
 public class SubscribedUserViewModel extends AndroidViewModel {
     private SubscribedUserRepository mSubscribedUserRepository;
     private LiveData<List<SubscribedUserData>> mAllSubscribedUsers;
 
-    public SubscribedUserViewModel(Application application) {
+    public SubscribedUserViewModel(Application application, RedditDataRoomDatabase redditDataRoomDatabase, String accountName) {
         super(application);
-        mSubscribedUserRepository = new SubscribedUserRepository(application);
+        mSubscribedUserRepository = new SubscribedUserRepository(redditDataRoomDatabase, accountName);
         mAllSubscribedUsers = mSubscribedUserRepository.getAllSubscribedSubreddits();
     }
 
@@ -23,4 +29,22 @@ public class SubscribedUserViewModel extends AndroidViewModel {
     public void insert(SubscribedUserData subscribedUserData) {
         mSubscribedUserRepository.insert(subscribedUserData);
     }
+
+    public static class Factory extends ViewModelProvider.NewInstanceFactory {
+        private Application mApplication;
+        private RedditDataRoomDatabase mRedditDataRoomDatabase;
+        private String mAccountName;
+
+        public Factory(Application application, RedditDataRoomDatabase redditDataRoomDatabase, String accountName) {
+            mApplication = application;
+            mRedditDataRoomDatabase = redditDataRoomDatabase;
+            mAccountName = accountName;
+        }
+
+        @NonNull
+        @Override
+        public <T extends ViewModel> T create(@NonNull Class<T> modelClass) {
+            return (T) new SubscribedUserViewModel(mApplication, mRedditDataRoomDatabase, mAccountName);
+        }
+    }
 }