#831 Migrate from SQLiteOpenHelper to Room

11 files changed, 149 insertions, 151 deletions

diff --git a/app/src/androidTest/java/it/niedermann/owncloud/notes/persistence/NotesNotesRoomDatabaseTest.java b/app/src/androidTest/java/it/niedermann/owncloud/notes/persistence/NotesNotesRoomDatabaseTest.java
index 44493fb1..71ab4b62 100644
--- a/app/src/androidTest/java/it/niedermann/owncloud/notes/persistence/NotesNotesRoomDatabaseTest.java
+++ b/app/src/androidTest/java/it/niedermann/owncloud/notes/persistence/NotesNotesRoomDatabaseTest.java
@@ -51,8 +51,7 @@ import static org.junit.Assert.fail;
 @FixMethodOrder(MethodSorters.NAME_ASCENDING)
 public class NotesNotesRoomDatabaseTest {
 
-    private NotesDatabase sqliteOpenHelperDatabase = null;
-    private NotesRoomDatabase roomDatabase = null;
+    private NotesRoomDatabase db = null;
 
     private String accountURL = "HelloHowAreYou";
     private String accountUserName = "John Doe";
@@ -62,23 +61,22 @@ public class NotesNotesRoomDatabaseTest {
     @Before
     public void setupDB() throws NextcloudHttpRequestFailedException {
         Context context = ApplicationProvider.getApplicationContext();
-        sqliteOpenHelperDatabase = NotesDatabase.getInstance(context);
-        roomDatabase = NotesRoomDatabase.getInstance(context);
+        db = NotesRoomDatabase.getInstance(context);
         // Create a new account if not exist
-        account = roomDatabase.getLocalAccountDao().getLocalAccountByAccountName(accountName);
+        account = db.getLocalAccountDao().getLocalAccountByAccountName(accountName);
         if (account == null) {
             final String response = "{\"ocs\":{\"meta\":{\"status\":\"ok\",\"statuscode\":200,\"message\":\"OK\"},\"data\":{\"version\":{\"major\":18,\"minor\":0,\"micro\":4,\"string\":\"18.0.4\",\"edition\":\"\",\"extendedSupport\":false},\"capabilities\":{\"core\":{\"pollinterval\":60,\"webdav-root\":\"remote.php\\/webdav\"},\"bruteforce\":{\"delay\":0},\"files\":{\"bigfilechunking\":true,\"blacklisted_files\":[\".htaccess\"],\"directEditing\":{\"url\":\"https:\\/\\/efss.qloud.my\\/ocs\\/v2.php\\/apps\\/files\\/api\\/v1\\/directEditing\",\"etag\":\"ed2b141af2a39b0e42666952ba60988d\"},\"versioning\":true,\"undelete\":true},\"activity\":{\"apiv2\":[\"filters\",\"filters-api\",\"previews\",\"rich-strings\"]},\"ocm\":{\"enabled\":true,\"apiVersion\":\"1.0-proposal1\",\"endPoint\":\"https:\\/\\/efss.qloud.my\\/index.php\\/ocm\",\"resourceTypes\":[{\"name\":\"file\",\"shareTypes\":[\"user\",\"group\"],\"protocols\":{\"webdav\":\"\\/public.php\\/webdav\\/\"}}]},\"deck\":{\"version\":\"0.8.2\"},\"richdocuments\":{\"mimetypes\":[\"application\\/vnd.oasis.opendocument.text\",\"application\\/vnd.oasis.opendocument.spreadsheet\",\"application\\/vnd.oasis.opendocument.graphics\",\"application\\/vnd.oasis.opendocument.presentation\",\"application\\/vnd.lotus-wordpro\",\"application\\/vnd.visio\",\"application\\/vnd.wordperfect\",\"application\\/msonenote\",\"application\\/msword\",\"application\\/rtf\",\"text\\/rtf\",\"application\\/vnd.openxmlformats-officedocument.wordprocessingml.document\",\"application\\/vnd.openxmlformats-officedocument.wordprocessingml.template\",\"application\\/vnd.ms-word.document.macroEnabled.12\",\"application\\/vnd.ms-word.template.macroEnabled.12\",\"application\\/vnd.ms-excel\",\"application\\/vnd.openxmlformats-officedocument.spreadsheetml.sheet\",\"application\\/vnd.openxmlformats-officedocument.spreadsheetml.template\",\"application\\/vnd.ms-excel.sheet.macroEnabled.12\",\"application\\/vnd.ms-excel.template.macroEnabled.12\",\"application\\/vnd.ms-excel.addin.macroEnabled.12\",\"application\\/vnd.ms-excel.sheet.binary.macroEnabled.12\",\"application\\/vnd.ms-powerpoint\",\"application\\/vnd.openxmlformats-officedocument.presentationml.presentation\",\"application\\/vnd.openxmlformats-officedocument.presentationml.template\",\"application\\/vnd.openxmlformats-officedocument.presentationml.slideshow\",\"application\\/vnd.ms-powerpoint.addin.macroEnabled.12\",\"application\\/vnd.ms-powerpoint.presentation.macroEnabled.12\",\"application\\/vnd.ms-powerpoint.template.macroEnabled.12\",\"application\\/vnd.ms-powerpoint.slideshow.macroEnabled.12\",\"text\\/csv\"],\"mimetypesNoDefaultOpen\":[\"image\\/svg+xml\",\"application\\/pdf\",\"text\\/plain\",\"text\\/spreadsheet\"],\"collabora\":[],\"direct_editing\":false,\"templates\":false,\"productName\":\"\\u5728\\u7ebf\\u534f\\u4f5c\"},\"dav\":{\"chunking\":\"1.0\"},\"files_sharing\":{\"api_enabled\":true,\"public\":{\"enabled\":true,\"password\":{\"enforced\":true,\"askForOptionalPassword\":false},\"expire_date\":{\"enabled\":true,\"days\":\"7\",\"enforced\":false},\"multiple_links\":true,\"expire_date_internal\":{\"enabled\":false},\"send_mail\":false,\"upload\":true,\"upload_files_drop\":true},\"resharing\":true,\"user\":{\"send_mail\":false,\"expire_date\":{\"enabled\":true}},\"group_sharing\":true,\"group\":{\"enabled\":true,\"expire_date\":{\"enabled\":true}},\"default_permissions\":31,\"federation\":{\"outgoing\":false,\"incoming\":false,\"expire_date\":{\"enabled\":true}},\"sharee\":{\"query_lookup_default\":false},\"sharebymail\":{\"enabled\":true,\"upload_files_drop\":{\"enabled\":true},\"password\":{\"enabled\":true},\"expire_date\":{\"enabled\":true}}},\"external\":{\"v1\":[\"sites\",\"device\",\"groups\",\"redirect\"]},\"notifications\":{\"ocs-endpoints\":[\"list\",\"get\",\"delete\",\"delete-all\",\"icons\",\"rich-strings\",\"action-web\"],\"push\":[\"devices\",\"object-data\",\"delete\"],\"admin-notifications\":[\"ocs\",\"cli\"]},\"password_policy\":{\"minLength\":8,\"enforceNonCommonPassword\":true,\"enforceNumericCharacters\":false,\"enforceSpecialCharacters\":false,\"enforceUpperLowerCase\":false,\"api\":{\"generate\":\"https:\\/\\/efss.qloud.my\\/ocs\\/v2.php\\/apps\\/password_policy\\/api\\/v1\\/generate\",\"validate\":\"https:\\/\\/efss.qloud.my\\/ocs\\/v2.php\\/apps\\/password_policy\\/api\\/v1\\/validate\"}},\"theming\":{\"name\":\"QloudData\",\"url\":\"https:\\/\\/www.qloud.my\\/qloud-data\\/\",\"slogan\":\"Powered by NextCloud\",\"color\":\"#1E4164\",\"color-text\":\"#ffffff\",\"color-element\":\"#1E4164\",\"logo\":\"https:\\/\\/efss.qloud.my\\/index.php\\/apps\\/theming\\/image\\/logo?useSvg=1&v=47\",\"background\":\"https:\\/\\/efss.qloud.my\\/core\\/img\\/background.png?v=47\",\"background-plain\":false,\"background-default\":true,\"logoheader\":\"https:\\/\\/efss.qloud.my\\/index.php\\/apps\\/theming\\/image\\/logo?useSvg=1&v=47\",\"favicon\":\"https:\\/\\/efss.qloud.my\\/index.php\\/apps\\/theming\\/image\\/logo?useSvg=1&v=47\"},\"registration\":{\"enabled\":true,\"apiRoot\":\"\\/ocs\\/v2.php\\/apps\\/registration\\/api\\/v1\\/\",\"apiLevel\":\"v1\"}}}}}";
             Capabilities capabilities = new Capabilities(response, null);
             assertNotNull(capabilities);
-            roomDatabase.addAccount(accountURL, accountUserName, accountName, capabilities);
-            account = roomDatabase.getLocalAccountDao().getLocalAccountByAccountName(accountName);
+            db.addAccount(accountURL, accountUserName, accountName, capabilities);
+            account = db.getLocalAccountDao().getLocalAccountByAccountName(accountName);
         }
     }
 
     @Test
     public void testSetUpEnv() {
-        Log.i("Test_DB_Instance", sqliteOpenHelperDatabase.toString());
-        List<LocalAccountEntity> accounts = roomDatabase.getLocalAccountDao().getAccounts();
+        Log.i("Test_DB_Instance", db.toString());
+        List<LocalAccountEntity> accounts = db.getLocalAccountDao().getAccounts();
         for (LocalAccountEntity account : accounts) {
             Log.i("Test_Get_Accounts", account.toString());
         }
@@ -93,14 +91,14 @@ public class NotesNotesRoomDatabaseTest {
                 true, "Diary", null);
 
         // Pre-check
-        List<NoteEntity> notes = roomDatabase.getNoteDao().getNotes(accountID);
+        List<NoteEntity> notes = db.getNoteDao().getNotes(accountID);
         int pre_size = notes.size();
         Log.i("Test_01_addNote_All_Notes_Before_Addition", "Size: " + pre_size);
 
         // Add a new note
-        long noteID = roomDatabase.addNote(accountID, cloudNote);
+        long noteID = db.addNote(accountID, cloudNote);
         // Check if this note is added successfully
-        NoteEntity note = roomDatabase.getNoteDao().getNote(accountID, noteID);
+        NoteEntity note = db.getNoteDao().getNote(accountID, noteID);
         Log.i("Test_01_addNote_Cur_Note", note.toString());
         Log.i("Test_01_addNote_Cur_Note", "Title: " + note.getTitle());
         Log.i("Test_01_addNote_Cur_Note", "Content: " + note.getContent());
@@ -109,10 +107,10 @@ public class NotesNotesRoomDatabaseTest {
         assertEquals("A Great Day", note.getTitle());
         assertEquals(cloudNote.getContent(), note.getContent());
         assertEquals("Diary", note.getCategory());
-        assertEquals(accountID, note.getAccountId());
+        assertEquals(accountID, note.getAccountId().longValue());
 
         // Check if this note is in all notes
-        notes = roomDatabase.getNoteDao().getNotes(accountID);
+        notes = db.getNoteDao().getNotes(accountID);
         int added_size = notes.size();
         assertEquals(1, added_size - pre_size);
 
@@ -125,13 +123,13 @@ public class NotesNotesRoomDatabaseTest {
         NoteEntity cloudNote_re0 = new NoteEntity(0, Calendar.getInstance(),
                 "A Bad Day", getCurDate() + " You're faking a smile with just a coffee to go (Daniel Powter).",
                 true, "A Nice Song", null);
-        noteID = roomDatabase.addNote(accountID, cloudNote_re0);
-        note = roomDatabase.getNoteDao().getNote(accountID, noteID);
+        noteID = db.addNote(accountID, cloudNote_re0);
+        note = db.getNoteDao().getNote(accountID, noteID);
         // Check
         assertEquals("A Bad Day", note.getTitle());
         assertEquals(cloudNote_re0.getContent(), note.getContent());
         assertEquals("A Nice Song", note.getCategory());
-        assertEquals(accountID, note.getAccountId());
+        assertEquals(accountID, note.getAccountId().longValue());
     }
 
     @Test
@@ -141,10 +139,10 @@ public class NotesNotesRoomDatabaseTest {
 
             // get a new note id to avoid UNIQUE Note_ID constraint
             // getNotesCustom also tested here
-            Method getNC = NotesDatabase.class.getDeclaredMethod("getNotesCustom", long.class, String.class, String[].class, String.class, boolean.class);
+            Method getNC = NotesRoomDatabase.class.getDeclaredMethod("getNotesCustom", long.class, String.class, String[].class, String.class, boolean.class);
             getNC.setAccessible(true);
-            List<NoteEntity> notes = (List<NoteEntity>) getNC.invoke(sqliteOpenHelperDatabase, accountID, NotesDatabase.key_status + " != ? AND " + NotesDatabase.key_account_id + " = ?",
-                    new String[]{DBStatus.LOCAL_DELETED.getTitle(), "" + accountID}, NotesDatabase.key_id + " ASC", false);
+            List<NoteEntity> notes = (List<NoteEntity>) getNC.invoke(db, accountID, "status != ? AND accountId = ?",
+                    new String[]{DBStatus.LOCAL_DELETED.getTitle(), "" + accountID}, "id ASC", false);
             long newNoteID = notes.get(notes.size() - 1).getId() + 1;   // avoid UNIQUE Note_ID constraint
 
             // Create a DBNote for argument passing
@@ -154,9 +152,9 @@ public class NotesNotesRoomDatabaseTest {
                     accountID, NoteUtil.generateNoteExcerpt(newContent, "Test-Title"), 0);
 
             // Add a new note
-            long noteID = roomDatabase.addNote(accountID, dbNote);
+            long noteID = db.addNote(accountID, dbNote);
             // Check if this note is added successfully
-            NoteEntity note = roomDatabase.getNoteDao().getNote(accountID, noteID);
+            NoteEntity note = db.getNoteDao().getNote(accountID, noteID);
             assertEquals(dbNote.getTitle(), note.getTitle());
             assertEquals(dbNote.getContent(), note.getContent());
             assertEquals(dbNote.getCategory(), note.getCategory());
@@ -168,19 +166,19 @@ public class NotesNotesRoomDatabaseTest {
                     newContent, true, "Sincere Friend's Record", null, DBStatus.VOID,
                     accountID, NoteUtil.generateNoteExcerpt(newContent, "Test-Title"), 0);
             // Add a new note
-            noteID = roomDatabase.addNote(accountID, dbNote);
+            noteID = db.addNote(accountID, dbNote);
             // Check if this note is added successfully
-            note = roomDatabase.getNoteDao().getNote(accountID, noteID);
+            note = db.getNoteDao().getNote(accountID, noteID);
             assertEquals(dbNote.getTitle(), note.getTitle());
             assertEquals(dbNote.getContent(), note.getContent());
             assertEquals(dbNote.getCategory(), note.getCategory());
             assertEquals(dbNote.getAccountId(), note.getAccountId());
 
             // Test the rest case of getNotesCustom - ORDER BY ~ null, LIMIT ~ not null
-            Method getNCWOW = NotesDatabase.class.getDeclaredMethod("getNotesCustom", long.class, String.class, String[].class, String.class, String.class, boolean.class);
+            Method getNCWOW = NotesRoomDatabase.class.getDeclaredMethod("getNotesCustom", long.class, String.class, String[].class, String.class, String.class, boolean.class);
             getNCWOW.setAccessible(true);
             int aSize = 1;
-            notes = (List<NoteEntity>) getNCWOW.invoke(sqliteOpenHelperDatabase, accountID, NotesDatabase.key_status + " != ? AND " + NotesDatabase.key_account_id + " = ?",
+            notes = (List<NoteEntity>) getNCWOW.invoke(db, accountID, " status != ? AND accountId = ?",
                     new String[]{DBStatus.LOCAL_DELETED.getTitle(), "" + accountID}, null, String.valueOf(aSize), false);
             assertEquals(aSize, notes.size());
         } catch (Exception e) {
@@ -192,26 +190,26 @@ public class NotesNotesRoomDatabaseTest {
     @Test
     public void test_03_searchNotes() {
         long thisAccountID = account.getId();
-        List<NoteEntity> notes = roomDatabase.searchNotes(thisAccountID, null, null, false, null);  // All three added notes are marked as favorite
+        List<NoteEntity> notes = db.searchNotes(thisAccountID, null, null, false, null);  // All three added notes are marked as favorite
         Log.i("Test_03_searchNotes_Favorite_false", "Size: " + notes.size());
         assertEquals(notes.size(), 0);
 
-        notes = roomDatabase.searchNotes(thisAccountID, null, "Hello", true, null); // There is no category named "Hello"
+        notes = db.searchNotes(thisAccountID, null, "Hello", true, null); // There is no category named "Hello"
         Log.i("Test_03_searchNotes_Category_Hello", "Size: " + notes.size());
         assertEquals(notes.size(), 0);
 
-        notes = roomDatabase.searchNotes(thisAccountID, null, "Diary", true, null); // There is one category named "Diary"
+        notes = db.searchNotes(thisAccountID, null, "Diary", true, null); // There is one category named "Diary"
         Log.i("Test_03_searchNotes_Category_Diary_Favorite_True", "Size: " + notes.size());
         assertEquals(notes.size(), 1);
 
-        notes = roomDatabase.searchNotes(thisAccountID, null, null, null, null);    // Fetch all notes
+        notes = db.searchNotes(thisAccountID, null, null, null, null);    // Fetch all notes
         Log.i("Test_03_searchNotes_Three_NULL", "Size: " + notes.size());
         assertEquals(notes.size(), 4);  // We've added three test notes by now
     }
 
     @Test
     public void test_04_getCategories() {
-        List<NavigationAdapter.CategoryNavigationItem> categories = roomDatabase.getCategories(account.getId());
+        List<NavigationAdapter.CategoryNavigationItem> categories = db.getCategories(account.getId());
         boolean exitFlag = false;
         for (NavigationAdapter.NavigationItem categoryItem : categories) {
             Log.i("Test_04_getCategories_Item", String.format("%s | %s | %d | %d", categoryItem.id, categoryItem.label, categoryItem.count, categoryItem.icon));
@@ -224,7 +222,7 @@ public class NotesNotesRoomDatabaseTest {
 
     @Test
     public void test_05_searchCategories() {
-        List<NavigationAdapter.CategoryNavigationItem> categories = roomDatabase.searchCategories(account.getId(), "Dia");
+        List<NavigationAdapter.CategoryNavigationItem> categories = db.searchCategories(account.getId(), "Dia");
         boolean exitFlag = false;
         for (NavigationAdapter.NavigationItem categoryItem : categories) {
             Log.i("Test_05_searchCategories_Dia", String.format("%s | %s | %d | %d", categoryItem.id, categoryItem.label, categoryItem.count, categoryItem.icon));
@@ -234,7 +232,7 @@ public class NotesNotesRoomDatabaseTest {
         }
         assertTrue(exitFlag);
 
-        categories = roomDatabase.searchCategories(account.getId(), "Mike Chester Wang");
+        categories = db.searchCategories(account.getId(), "Mike Chester Wang");
         exitFlag = false;
         for (NavigationAdapter.NavigationItem categoryItem : categories) {
             Log.i("Test_05_searchCategories_Item_Mike_Chester_Wang", String.format("%s | %s | %d | %d", categoryItem.id, categoryItem.label, categoryItem.count, categoryItem.icon));
@@ -248,7 +246,7 @@ public class NotesNotesRoomDatabaseTest {
     @Test
     public void test_06_deleteNote() {
         long thisAccountID = account.getId();
-        List<NoteEntity> notes = roomDatabase.getNoteDao().getNotes(thisAccountID);
+        List<NoteEntity> notes = db.getNoteDao().getNotes(thisAccountID);
         int added_size = notes.size();
 
         Log.i("Test_06_deleteNote_All_Before_Deletion", "Size: " + added_size);
@@ -256,12 +254,12 @@ public class NotesNotesRoomDatabaseTest {
         for (NoteEntity cnote : notes) {
             Log.i("Test_06_deleteNote_All_Before_Deletion", cnote.toString());
             // Delete the note after testing
-            roomDatabase.deleteNote(cnote.getId(), cnote.getStatus());
+            db.deleteNote(cnote.getId(), cnote.getStatus());
             counter++;
         }
 
         // Check if the note is deleted successfully
-        notes = roomDatabase.getNoteDao().getNotes(thisAccountID);
+        notes = db.getNoteDao().getNotes(thisAccountID);
         int deleted_size = notes.size();
         assertEquals(counter, added_size - deleted_size);
         Log.i("Test_06_deleteNote_All_Notes_After_Deletion", "Size: " + deleted_size);
@@ -303,27 +301,27 @@ public class NotesNotesRoomDatabaseTest {
                 false, "Diary", null));
 
         // Pre-check
-        List<NoteEntity> notes = roomDatabase.getNoteDao().getNotes(thisAccountID);
+        List<NoteEntity> notes = db.getNoteDao().getNotes(thisAccountID);
         int pre_size = notes.size();
         Log.i("Test_07_multiAddNote_All_Notes_Before_Addition", "Size: " + pre_size);
 
         long[] multiNoteID = new long[10];
         for (int i = 0; i < 10; ++i) {
-            multiNoteID[i] = roomDatabase.addNote(thisAccountID, multiCloudNote.get(i));
+            multiNoteID[i] = db.addNote(thisAccountID, multiCloudNote.get(i));
         }
 
         // check if the node added successfully
         for (int i = 0; i < 10; ++i) {
-            NoteEntity nodeTemp = NoteEntity.entityToDBNote(roomDatabase.getNoteDao().getNote(thisAccountID, multiNoteID[i]));
+            NoteEntity nodeTemp = db.getNoteDao().getNote(thisAccountID, multiNoteID[i]);
             assertEquals(nodeTemp.getTitle(), multiCloudNote.get(i).getTitle());
             assertEquals(nodeTemp.getCategory(), multiCloudNote.get(i).getCategory());
             assertEquals(nodeTemp.getContent(), multiCloudNote.get(i).getContent());
-            assertEquals(nodeTemp.getAccountId(), thisAccountID);
+            assertEquals(nodeTemp.getAccountId().longValue(), thisAccountID);
             Log.i("Test_07_multiAddNote_All_Notes_Addition_sucessful", nodeTemp.toString());
         }
 
         // check if these note is in all notes
-        notes = roomDatabase.getNoteDao().getNotes(thisAccountID);
+        notes = db.getNoteDao().getNotes(thisAccountID);
         int add_size = notes.size();
         assertEquals(10, add_size - pre_size);
 
@@ -333,34 +331,34 @@ public class NotesNotesRoomDatabaseTest {
     @Test
     public void test_08_multiSearchNotes() {
         long thisAccountID = account.getId();
-        List<NoteEntity> notes = roomDatabase.searchNotes(thisAccountID, null, null, null, null);
+        List<NoteEntity> notes = db.searchNotes(thisAccountID, null, null, null, null);
         Log.i("Test_08_multiSearchNotes_null_null_null", "Size: " + notes.size());
         assertEquals(notes.size(), 10);
 
-        notes = roomDatabase.searchNotes(thisAccountID, null, null, true, null);
+        notes = db.searchNotes(thisAccountID, null, null, true, null);
         Log.i("Test_08_multiSearchNotes_null_null_true", "Size: " + notes.size());
         assertEquals(notes.size(), 7);
 
-        notes = roomDatabase.searchNotes(thisAccountID, null, "Music", null, null);
+        notes = db.searchNotes(thisAccountID, null, "Music", null, null);
         Log.i("Test_08_multiSearchNotes_null_Music_null", "Size: " + notes.size());
         assertEquals(notes.size(), 2);
 
-        notes = roomDatabase.searchNotes(thisAccountID, null, "Work", true, null);
+        notes = db.searchNotes(thisAccountID, null, "Work", true, null);
         Log.i("Test_08_multiSearchNotes_null_Work_true", "Size: " + notes.size());
         assertEquals(notes.size(), 0);
 
-        notes = roomDatabase.searchNotes(thisAccountID, null, "Diary", null, null);
+        notes = db.searchNotes(thisAccountID, null, "Diary", null, null);
         Log.i("Test_08_multiSearchNotes_null_Diary_null", "Size: " + notes.size());
         assertEquals(notes.size(), 1);
 
-        notes = roomDatabase.searchNotes(thisAccountID, "Mike", null, null, null);
+        notes = db.searchNotes(thisAccountID, "Mike", null, null, null);
         Log.i("Test_08_multiSearchNotes_Mike_null_null", "Size: " + notes.size());
         assertEquals(notes.size(), 1);
     }
 
     @Test
     public void test_09_multiGetCategories() {
-        List<NavigationAdapter.CategoryNavigationItem> categories = roomDatabase.getCategories(account.getId());
+        List<NavigationAdapter.CategoryNavigationItem> categories = db.getCategories(account.getId());
         int count = 0;
         for (NavigationAdapter.NavigationItem categoryItem : categories) {
             Log.i("Test_09_multiGetCategories_Item", String.format("%s | %s | %d | %d", categoryItem.id, categoryItem.label, categoryItem.count, categoryItem.icon));
@@ -373,7 +371,7 @@ public class NotesNotesRoomDatabaseTest {
 
     @Test
     public void test_10_multiSearchCategories() {
-        List<NavigationAdapter.CategoryNavigationItem> categories = roomDatabase.searchCategories(account.getId(), "M");
+        List<NavigationAdapter.CategoryNavigationItem> categories = db.searchCategories(account.getId(), "M");
         int count = 0;
         for (NavigationAdapter.NavigationItem categoryItem : categories) {
             Log.i("Test_10_multiSearchCategories_Item", String.format("%s | %s | %d | %d", categoryItem.id, categoryItem.label, categoryItem.count, categoryItem.icon));
@@ -381,7 +379,7 @@ public class NotesNotesRoomDatabaseTest {
         }
         assertEquals(3, count);
 
-        categories = roomDatabase.searchCategories(account.getId(), "Mike");
+        categories = db.searchCategories(account.getId(), "Mike");
         count = 0;
         for (NavigationAdapter.NavigationItem categoryItem : categories) {
             Log.i("Test_10_multiSearchCategories_Item", String.format("%s | %s | %d | %d", categoryItem.id, categoryItem.label, categoryItem.count, categoryItem.icon));
@@ -389,7 +387,7 @@ public class NotesNotesRoomDatabaseTest {
         }
         assertEquals(0, count);
 
-        categories = roomDatabase.searchCategories(account.getId(), "M");
+        categories = db.searchCategories(account.getId(), "M");
         boolean exitFlag = false;
         for (NavigationAdapter.NavigationItem categoryItem : categories) {
             Log.i("Test_10_multiSearchCategories_Item", String.format("%s | %s | %d | %d", categoryItem.id, categoryItem.label, categoryItem.count, categoryItem.icon));
@@ -400,7 +398,7 @@ public class NotesNotesRoomDatabaseTest {
         assertTrue(exitFlag);
 
 
-        categories = roomDatabase.searchCategories(account.getId(), "WOk");
+        categories = db.searchCategories(account.getId(), "WOk");
         exitFlag = false;
         for (NavigationAdapter.NavigationItem categoryItem : categories) {
             Log.i("Test_10_multiSearchCategories_Item", String.format("%s | %s | %d | %d", categoryItem.id, categoryItem.label, categoryItem.count, categoryItem.icon));
@@ -410,7 +408,7 @@ public class NotesNotesRoomDatabaseTest {
         }
         assertFalse(exitFlag);
 
-        categories = roomDatabase.searchCategories(account.getId(), "hello");
+        categories = db.searchCategories(account.getId(), "hello");
         exitFlag = false;
         for (NavigationAdapter.NavigationItem categoryItem : categories) {
             Log.i("Test_10_multiSearchCategories_Item", String.format("%s | %s | %d | %d", categoryItem.id, categoryItem.label, categoryItem.count, categoryItem.icon));
@@ -424,17 +422,17 @@ public class NotesNotesRoomDatabaseTest {
     @Test
     public void test_11_multiDeleteNote() {
         long thisAccountID = account.getId();
-        List<NoteEntity> notes = roomDatabase.getNoteDao().getNotes(thisAccountID);
+        List<NoteEntity> notes = db.getNoteDao().getNotes(thisAccountID);
         int added_size = notes.size();
 
         Log.i("Test_11_multiDeleteNote_All_Before_Deletion", "Size: " + added_size);
         for (NoteEntity e : notes) {
             Log.i("Test_11_multiDeleteNote_All_Before_Deletion", e.toString());
-            roomDatabase.deleteNote(e.getId(), e.getStatus());
+            db.deleteNote(e.getId(), e.getStatus());
         }
 
         // Check if the note is deleted successfully
-        notes = roomDatabase.getNoteDao().getNotes(thisAccountID);
+        notes = db.getNoteDao().getNotes(thisAccountID);
         int deleted_size = notes.size();
         assertEquals(10, added_size - deleted_size);
         Log.i("Test_11_multiDeleteNote_All_After_Deletion", "Size: " + deleted_size);
@@ -448,14 +446,14 @@ public class NotesNotesRoomDatabaseTest {
                 true, "日记", null);
 
         // Pre-check
-        List<NoteEntity> notes = roomDatabase.getNoteDao().getNotes(accountID);
+        List<NoteEntity> notes = db.getNoteDao().getNotes(accountID);
         int pre_size = notes.size();
         Log.i("Test_12_Chinese_All_Notes_Before_Addition", "Size: " + pre_size);
 
         // Add a new note
-        long noteID = roomDatabase.addNote(accountID, cloudNote);
+        long noteID = db.addNote(accountID, cloudNote);
         // Check if this note is added successfully
-        NoteEntity note = roomDatabase.getNoteDao().getNote(accountID, noteID);
+        NoteEntity note = db.getNoteDao().getNote(accountID, noteID);
         Log.i("Test_12_Chinese_Cur_Note", note.toString());
         Log.i("Test_12_Chinese_Cur_Note", "Title: " + note.getTitle());
         Log.i("Test_12_Chinese_Cur_Note", "Content: " + note.getContent());
@@ -464,10 +462,10 @@ public class NotesNotesRoomDatabaseTest {
         assertEquals("美好的一天", note.getTitle());
         assertEquals(cloudNote.getContent(), note.getContent());
         assertEquals("日记", note.getCategory());
-        assertEquals(accountID, note.getAccountId());
+        assertEquals(accountID, note.getAccountId().longValue());
 
         // Check if this note is in all notes
-        notes = roomDatabase.getNoteDao().getNotes(accountID);
+        notes = db.getNoteDao().getNotes(accountID);
         int added_size = notes.size();
 
         assertEquals(1, added_size - pre_size);
@@ -478,11 +476,11 @@ public class NotesNotesRoomDatabaseTest {
         }
 
         long thisAccountID = account.getId();
-        notes = roomDatabase.searchNotes(thisAccountID, "美好", "日记", true, null);
+        notes = db.searchNotes(thisAccountID, "美好", "日记", true, null);
         Log.i("Test_12_Chinese", "Size: " + notes.size());
         assertEquals(1, notes.size());
 
-        List<NavigationAdapter.CategoryNavigationItem> categories = roomDatabase.getCategories(account.getId());
+        List<NavigationAdapter.CategoryNavigationItem> categories = db.getCategories(account.getId());
         boolean exitFlag = false;
         for (NavigationAdapter.NavigationItem categoryItem : categories) {
             Log.i("Test_12_Chinese_Item", String.format("%s | %s | %d | %d", categoryItem.id, categoryItem.label, categoryItem.count, categoryItem.icon));
@@ -492,7 +490,7 @@ public class NotesNotesRoomDatabaseTest {
         }
         assertTrue(exitFlag);
 
-        categories = roomDatabase.searchCategories(account.getId(), "记");
+        categories = db.searchCategories(account.getId(), "记");
         exitFlag = false;
         for (NavigationAdapter.NavigationItem categoryItem : categories) {
             Log.i("Test_12_Chinese_Item", String.format("%s | %s | %d | %d", categoryItem.id, categoryItem.label, categoryItem.count, categoryItem.icon));
@@ -502,15 +500,15 @@ public class NotesNotesRoomDatabaseTest {
         }
         assertTrue(exitFlag);
 
-        notes = roomDatabase.getNoteDao().getNotes(thisAccountID);
+        notes = db.getNoteDao().getNotes(thisAccountID);
         for (NoteEntity cnote : notes) {
             Log.i("Test_12_Chinese_All_Before_Deletion", cnote.toString());
             // Delete the note after testing
-            roomDatabase.deleteNote(cnote.getId(), cnote.getStatus());
+            db.deleteNote(cnote.getId(), cnote.getStatus());
         }
 
         // Check if the note is deleted successfully
-        notes = roomDatabase.getNoteDao().getNotes(thisAccountID);
+        notes = db.getNoteDao().getNotes(thisAccountID);
         int deleted_size = notes.size();
         assertEquals(1, added_size - deleted_size);
         Log.i("Test_12_Chinese_All_Notes_After_Deletion", "Size: " + deleted_size);
@@ -519,12 +517,12 @@ public class NotesNotesRoomDatabaseTest {
     @Test
     public void test_13_getCategoryIdByTitle() {
         try {
-            Method method = NotesDatabase.class.getDeclaredMethod("getCategoryIdByTitle",
+            Method method = NotesRoomDatabase.class.getDeclaredMethod("getCategoryIdByTitle",
                     long.class,
                     String.class);
             method.setAccessible(true);
 
-            List<NavigationAdapter.CategoryNavigationItem> categories = roomDatabase.getCategories(account.getId());
+            List<NavigationAdapter.CategoryNavigationItem> categories = db.getCategories(account.getId());
             int count = 0;
             for (NavigationAdapter.NavigationItem categoryItem : categories) {
                 Log.i("Test_13_getCategoryIdByTitle", String.format("%s | %s | %d | %d",
@@ -537,13 +535,13 @@ public class NotesNotesRoomDatabaseTest {
 
             // Find an existing category to test false
             if (count > 0) {
-                catID = (int) method.invoke(sqliteOpenHelperDatabase, account.getId(), categories.get(0).label);
+                catID = (int) method.invoke(db, account.getId(), categories.get(0).label);
                 assertNotEquals(-1, catID);
             }
 
             // Create a category not existing
             String cur_cat = "Mike Chester Wang's Diary" + getCurDate();
-            catID = (int) method.invoke(sqliteOpenHelperDatabase, account.getId(), cur_cat);
+            catID = (int) method.invoke(db, account.getId(), cur_cat);
             assertNotEquals(-1, catID);
         } catch (Exception e) {
             fail(Arrays.toString(e.getStackTrace()));
@@ -567,19 +565,19 @@ public class NotesNotesRoomDatabaseTest {
         NoteEntity cloudNote = new NoteEntity(1, Calendar.getInstance(),
                 "A Coding Day", "This is a day which is very suitable to code.",
                 true, "CodingDiary", null);
-        long noteID = roomDatabase.addNote(account.getId(), cloudNote);
+        long noteID = db.addNote(account.getId(), cloudNote);
 
         // check the default value of ordering_method
-        CategorySortingMethod defaultMethod = roomDatabase.getCategoryDao().getCategoryOrderByTitle(account.getId(), "CodingDiary");
+        CategorySortingMethod defaultMethod = db.getCategoryDao().getCategoryOrderByTitle(account.getId(), "CodingDiary");
         assertEquals(defaultMethod, CategorySortingMethod.getCSM(0));
 
         // modify the value of ordering_method and check
-        roomDatabase.getCategoryDao().modifyCategoryOrderByTitle(account.getId(), "CodingDiary", CategorySortingMethod.getCSM(1));
-        CategorySortingMethod methodAfterModify = roomDatabase.getCategoryDao().getCategoryOrderByTitle(account.getId(), "CodingDiary");
+        db.getCategoryDao().modifyCategoryOrderByTitle(account.getId(), "CodingDiary", CategorySortingMethod.getCSM(1));
+        CategorySortingMethod methodAfterModify = db.getCategoryDao().getCategoryOrderByTitle(account.getId(), "CodingDiary");
         assertEquals(methodAfterModify, CategorySortingMethod.getCSM(1));
 
         // delete the Node
-        roomDatabase.deleteNote(noteID, DBStatus.VOID);
+        db.deleteNote(noteID, DBStatus.VOID);
     }
 
     @Test
@@ -589,53 +587,53 @@ public class NotesNotesRoomDatabaseTest {
         NoteEntity cloudNote = new NoteEntity(1, Calendar.getInstance(),
                 "A Coding Day", "This is a day which is very suitable to code.",
                 true, "CodingDiary", null);
-        long noteID = roomDatabase.addNote(account.getId(), cloudNote);
+        long noteID = db.addNote(account.getId(), cloudNote);
 
         // check the default value of ordering_method
-        CategorySortingMethod defaultMethod = roomDatabase.getCategoryOrder(account.getId(), new Category("CodingDiary", false));
+        CategorySortingMethod defaultMethod = db.getCategoryOrder(account.getId(), new Category("CodingDiary", false));
         assertEquals(defaultMethod, CategorySortingMethod.getCSM(0));
 
         // modify the value of ordering_method and check
-        roomDatabase.getCategoryDao().modifyCategoryOrderByTitle(account.getId(), "CodingDiary", CategorySortingMethod.getCSM(1));
-        CategorySortingMethod methodAfterModify = roomDatabase.getCategoryOrder(account.getId(), new Category("CodingDiary", false));
+        db.getCategoryDao().modifyCategoryOrderByTitle(account.getId(), "CodingDiary", CategorySortingMethod.getCSM(1));
+        CategorySortingMethod methodAfterModify = db.getCategoryOrder(account.getId(), new Category("CodingDiary", false));
         assertEquals(methodAfterModify, CategorySortingMethod.getCSM(1));
 
         // delete the Node
-        roomDatabase.deleteNote(noteID, DBStatus.VOID);
+        db.deleteNote(noteID, DBStatus.VOID);
 
         // Special categories
-        Context ctx = sqliteOpenHelperDatabase.getContext().getApplicationContext();
+        Context ctx = db.getContext().getApplicationContext();
         SharedPreferences sp = PreferenceManager.getDefaultSharedPreferences(ctx);
         SharedPreferences.Editor spe = sp.edit();
         spe.clear();
         spe.apply();
         // check default value
         // all notes
-        defaultMethod = roomDatabase.getCategoryOrder(account.getId(), new Category(null, false));
+        defaultMethod = db.getCategoryOrder(account.getId(), new Category(null, false));
         assertEquals(defaultMethod, CategorySortingMethod.getCSM(0));
 
         // uncategorized
-        defaultMethod = roomDatabase.getCategoryOrder(account.getId(), new Category("", false));
+        defaultMethod = db.getCategoryOrder(account.getId(), new Category("", false));
         assertEquals(defaultMethod, CategorySortingMethod.getCSM(0));
 
         // favorite
-        defaultMethod = roomDatabase.getCategoryOrder(account.getId(), new Category(null, true));
+        defaultMethod = db.getCategoryOrder(account.getId(), new Category(null, true));
         assertEquals(defaultMethod, CategorySortingMethod.getCSM(0));
 
         // modify the value of ordering_method and check
         // all notes
-        roomDatabase.modifyCategoryOrder(account.getId(), new Category(null, false), CategorySortingMethod.getCSM(1));
-        methodAfterModify = roomDatabase.getCategoryOrder(account.getId(), new Category(null, false));
+        db.modifyCategoryOrder(account.getId(), new Category(null, false), CategorySortingMethod.getCSM(1));
+        methodAfterModify = db.getCategoryOrder(account.getId(), new Category(null, false));
         assertEquals(methodAfterModify, CategorySortingMethod.getCSM(1));
 
         // uncategorized
-        roomDatabase.modifyCategoryOrder(account.getId(), new Category("", false), CategorySortingMethod.getCSM(1));
-        methodAfterModify = roomDatabase.getCategoryOrder(account.getId(), new Category("", false));
+        db.modifyCategoryOrder(account.getId(), new Category("", false), CategorySortingMethod.getCSM(1));
+        methodAfterModify = db.getCategoryOrder(account.getId(), new Category("", false));
         assertEquals(methodAfterModify, CategorySortingMethod.getCSM(1));
 
         // favorite
-        roomDatabase.modifyCategoryOrder(account.getId(), new Category(null, true), CategorySortingMethod.getCSM(1));
-        methodAfterModify = roomDatabase.getCategoryOrder(account.getId(), new Category(null, true));
+        db.modifyCategoryOrder(account.getId(), new Category(null, true), CategorySortingMethod.getCSM(1));
+        methodAfterModify = db.getCategoryOrder(account.getId(), new Category(null, true));
         assertEquals(methodAfterModify, CategorySortingMethod.getCSM(1));
 
         // delete SharedPreferences
diff --git a/app/src/main/java/it/niedermann/owncloud/notes/AppendToNoteActivity.java b/app/src/main/java/it/niedermann/owncloud/notes/AppendToNoteActivity.java
index 8c4a6fca..d397203b 100644
--- a/app/src/main/java/it/niedermann/owncloud/notes/AppendToNoteActivity.java
+++ b/app/src/main/java/it/niedermann/owncloud/notes/AppendToNoteActivity.java
@@ -36,7 +36,7 @@ public class AppendToNoteActivity extends MainActivity {
     @Override
     public void onNoteClick(int position, View v) {
         if (receivedText != null && receivedText.length() > 0) {
-            final NoteEntity note = roomDatabase.getNoteDao().getNote(localAccount.getId(), ((NoteEntity) adapter.getItem(position)).getId());
+            final NoteEntity note = db.getNoteDao().getNote(localAccount.getId(), ((NoteEntity) adapter.getItem(position)).getId());
             final String oldContent = note.getContent();
             String newContent;
             if (oldContent != null && oldContent.length() > 0) {
@@ -44,7 +44,7 @@ public class AppendToNoteActivity extends MainActivity {
             } else {
                 newContent = receivedText;
             }
-            roomDatabase.updateNoteAndSync(ssoAccount, localAccount, note, newContent, null, () -> Toast.makeText(this, getString(R.string.added_content, receivedText), Toast.LENGTH_SHORT).show());
+            db.updateNoteAndSync(ssoAccount, localAccount, note, newContent, null, () -> Toast.makeText(this, getString(R.string.added_content, receivedText), Toast.LENGTH_SHORT).show());
         } else {
             Toast.makeText(this, R.string.shared_text_empty, Toast.LENGTH_SHORT).show();
         }
diff --git a/app/src/main/java/it/niedermann/owncloud/notes/main/MainActivity.java b/app/src/main/java/it/niedermann/owncloud/notes/main/MainActivity.java
index c99293ae..e44701a4 100644
--- a/app/src/main/java/it/niedermann/owncloud/notes/main/MainActivity.java
+++ b/app/src/main/java/it/niedermann/owncloud/notes/main/MainActivity.java
@@ -138,7 +138,7 @@ public class MainActivity extends LockedActivity implements NoteClickListener, V
 
     protected ItemAdapter adapter;
 
-    protected NotesRoomDatabase roomDatabase = null;
+    protected NotesRoomDatabase db = null;
     private NavigationAdapter adapterCategories;
     private NavigationItem itemRecent;
     private NavigationItem itemFavorites;
@@ -189,14 +189,14 @@ public class MainActivity extends LockedActivity implements NoteClickListener, V
             categoryAdapterSelectedItem = savedInstanceState.getString(SAVED_STATE_NAVIGATION_ADAPTER_SLECTION);
         }
 
-        roomDatabase = NotesRoomDatabase.getInstance(this);
+        db = NotesRoomDatabase.getInstance(this);
 
         gridView = isGridViewEnabled();
         if (!gridView || isDarkThemeActive(this)) {
             activityBinding.activityNotesListView.setBackgroundColor(ContextCompat.getColor(this, R.color.primary));
         }
 
-        LocalAccountDao dao = roomDatabase.getLocalAccountDao();
+        LocalAccountDao dao = db.getLocalAccountDao();
         new Thread(() -> {
             List<LocalAccountEntity> localAccountEntities = dao.getAccounts();
             Log.v("TEST", localAccountEntities.size() + " acs");
@@ -206,7 +206,7 @@ public class MainActivity extends LockedActivity implements NoteClickListener, V
         setupNavigationMenu();
         setupNotesList();
 
-        new Thread(() -> canMoveNoteToAnotherAccounts = roomDatabase.getLocalAccountDao().getAccountsCount() > 1).start();
+        new Thread(() -> canMoveNoteToAnotherAccounts = db.getLocalAccountDao().getAccountsCount() > 1).start();
     }
 
     @Override
@@ -218,7 +218,7 @@ public class MainActivity extends LockedActivity implements NoteClickListener, V
             }
         } catch (NoCurrentAccountSelectedException | NextcloudFilesAppAccountNotFoundException e) {
             if (localAccount == null) {
-                List<LocalAccountEntity> localAccounts = roomDatabase.getLocalAccountDao().getAccounts();
+                List<LocalAccountEntity> localAccounts = db.getLocalAccountDao().getAccounts();
                 if (localAccounts.size() > 0) {
                     localAccount = localAccounts.get(0);
                 }
@@ -232,7 +232,7 @@ public class MainActivity extends LockedActivity implements NoteClickListener, V
         refreshLists();
         if (localAccount != null) {
             synchronize();
-            roomDatabase.getNoteServerSyncHelper().addCallbackPull(ssoAccount, syncCallBack);
+            db.getNoteServerSyncHelper().addCallbackPull(ssoAccount, syncCallBack);
         }
         super.onResume();
     }
@@ -250,12 +250,12 @@ public class MainActivity extends LockedActivity implements NoteClickListener, V
     private void selectAccount(String accountName) {
         fabCreate.hide();
         SingleAccountHelper.setCurrentAccount(getApplicationContext(), accountName);
-        localAccount = roomDatabase.getLocalAccountDao().getLocalAccountByAccountName(accountName);
+        localAccount = db.getLocalAccountDao().getLocalAccountByAccountName(accountName);
         if (localAccount != null) {
             try {
                 BrandingUtil.saveBrandColors(this, Color.parseColor(localAccount.getColor()), Color.parseColor(localAccount.getTextColor()));
                 ssoAccount = SingleAccountHelper.getCurrentSingleSignOnAccount(getApplicationContext());
-                new NotesListViewItemTouchHelper(ssoAccount, this, roomDatabase, adapter, syncCallBack, this::refreshLists, swipeRefreshLayout, this, gridView)
+                new NotesListViewItemTouchHelper(ssoAccount, this, db, adapter, syncCallBack, this::refreshLists, swipeRefreshLayout, this, gridView)
                         .attachToRecyclerView(listView);
                 synchronize();
             } catch (NextcloudFilesAppAccountNotFoundException | NoCurrentAccountSelectedException e) {
@@ -372,12 +372,12 @@ public class MainActivity extends LockedActivity implements NoteClickListener, V
                     final Capabilities capabilities;
                     try {
                         capabilities = CapabilitiesClient.getCapabilities(getApplicationContext(), ssoAccount, localAccount.getCapabilitiesETag());
-                        roomDatabase.getLocalAccountDao().updateCapabilitiesETag(localAccount.getId(), capabilities.getETag());
-                        roomDatabase.updateBrand(localAccount.getId(), capabilities);
+                        db.getLocalAccountDao().updateCapabilitiesETag(localAccount.getId(), capabilities.getETag());
+                        db.updateBrand(localAccount.getId(), capabilities);
                         localAccount.setColor(capabilities.getColor());
                         localAccount.setTextColor(capabilities.getTextColor());
                         BrandingUtil.saveBrandColors(this, Color.parseColor(localAccount.getColor()), Color.parseColor(localAccount.getTextColor()));
-                        roomDatabase.updateApiVersion(localAccount.getId(), capabilities.getApiVersion());
+                        db.updateApiVersion(localAccount.getId(), capabilities.getApiVersion());
                         Log.i(TAG, capabilities.toString());
                     } catch (Exception e) {
                         if (e instanceof NextcloudHttpRequestFailedException && ((NextcloudHttpRequestFailedException) e).getStatusCode() == HttpURLConnection.HTTP_NOT_MODIFIED) {
@@ -407,14 +407,14 @@ public class MainActivity extends LockedActivity implements NoteClickListener, V
         activityBinding.sortingMethod.setOnClickListener((v) -> {
             CategorySortingMethod method;
 
-            method = roomDatabase.getCategoryOrder(localAccount.getId(), navigationSelection);
+            method = db.getCategoryOrder(localAccount.getId(), navigationSelection);
 
             if (method == CategorySortingMethod.SORT_LEXICOGRAPHICAL_ASC) {
                 method = CategorySortingMethod.SORT_MODIFIED_DESC;
             } else {
                 method = CategorySortingMethod.SORT_LEXICOGRAPHICAL_ASC;
             }
-            roomDatabase.modifyCategoryOrder(localAccount.getId(), navigationSelection, method);
+            db.modifyCategoryOrder(localAccount.getId(), navigationSelection, method);
             refreshLists();
             updateSortMethodIcon(localAccount.getId());
         });
@@ -517,7 +517,7 @@ public class MainActivity extends LockedActivity implements NoteClickListener, V
             if (localAccount == null) {
                 return new ArrayList<>();
             }
-            List<CategoryNavigationItem> categories = roomDatabase.getCategories(localAccount.getId());
+            List<CategoryNavigationItem> categories = db.getCategories(localAccount.getId());
             if (!categories.isEmpty() && categories.get(0).label.isEmpty()) {
                 itemUncategorized = categories.get(0);
                 itemUncategorized.label = getString(R.string.action_uncategorized);
@@ -526,8 +526,8 @@ public class MainActivity extends LockedActivity implements NoteClickListener, V
                 itemUncategorized = null;
             }
 
-            int numFavorites = roomDatabase.getNoteDao().getFavoritesCount(localAccount.getId());
-            int numNonFavorites = roomDatabase.getNoteDao().getNonFavoritesCount(localAccount.getId());
+            int numFavorites = db.getNoteDao().getFavoritesCount(localAccount.getId());
+            int numNonFavorites = db.getNoteDao().getNonFavoritesCount(localAccount.getId());
             itemFavorites.count = numFavorites;
             itemRecent.count = numFavorites + numNonFavorites;
 
@@ -708,7 +708,7 @@ public class MainActivity extends LockedActivity implements NoteClickListener, V
      * Updates sorting method icon.
      */
     private void updateSortMethodIcon(long localAccountId) {
-        CategorySortingMethod method = roomDatabase.getCategoryOrder(localAccountId, navigationSelection);
+        CategorySortingMethod method = db.getCategoryOrder(localAccountId, navigationSelection);
         if (method == CategorySortingMethod.SORT_LEXICOGRAPHICAL_ASC) {
             activityBinding.sortingMethod.setImageResource(R.drawable.alphabetical_asc);
             activityBinding.sortingMethod.setContentDescription(getString(R.string.sort_last_modified));
@@ -780,7 +780,7 @@ public class MainActivity extends LockedActivity implements NoteClickListener, V
                 if (resultCode == RESULT_FIRST_USER) {
                     selectAccount(null);
                 }
-                new Thread(() -> canMoveNoteToAnotherAccounts = roomDatabase.getLocalAccountDao().getAccountsCount() > 1).start();
+                new Thread(() -> canMoveNoteToAnotherAccounts = db.getLocalAccountDao().getAccountsCount() > 1).start();
                 break;
             }
             default: {
@@ -792,8 +792,8 @@ public class MainActivity extends LockedActivity implements NoteClickListener, V
                             try {
                                 Log.i(TAG, "Refreshing capabilities for " + ssoAccount.name);
                                 final Capabilities capabilities = CapabilitiesClient.getCapabilities(getApplicationContext(), ssoAccount, null);
-                                roomDatabase.addAccount(ssoAccount.url, ssoAccount.userId, ssoAccount.name, capabilities);
-                                new Thread(() -> canMoveNoteToAnotherAccounts = roomDatabase.getLocalAccountDao().getAccountsCount() > 1).start();
+                                db.addAccount(ssoAccount.url, ssoAccount.userId, ssoAccount.name, capabilities);
+                                new Thread(() -> canMoveNoteToAnotherAccounts = db.getLocalAccountDao().getAccountsCount() > 1).start();
                                 Log.i(TAG, capabilities.toString());
                                 runOnUiThread(() -> selectAccount(ssoAccount.name));
                             } catch (SQLiteException e) {
@@ -801,7 +801,7 @@ public class MainActivity extends LockedActivity implements NoteClickListener, V
                                 runOnUiThread(() -> selectAccount(ssoAccount.name));
                             } catch (Exception e) {
                                 // Happens when importing an already existing account the second time
-                                if (e instanceof TokenMismatchException && roomDatabase.getLocalAccountDao().getLocalAccountByAccountName(ssoAccount.name) != null) {
+                                if (e instanceof TokenMismatchException && db.getLocalAccountDao().getLocalAccountByAccountName(ssoAccount.name) != null) {
                                     Log.w(TAG, "Received " + TokenMismatchException.class.getSimpleName() + " and the given ssoAccount.name (" + ssoAccount.name + ") does already exist in the database. Assume that this account has already been imported.");
                                     runOnUiThread(() -> {
                                         selectAccount(ssoAccount.name);
@@ -888,7 +888,7 @@ public class MainActivity extends LockedActivity implements NoteClickListener, V
         if (selected) {
             v.setSelected(true);
             mActionMode = startSupportActionMode(new MultiSelectedActionModeCallback(
-                    this, this, roomDatabase, localAccount.getId(), canMoveNoteToAnotherAccounts, adapter, listView, this::refreshLists, getSupportFragmentManager(), activityBinding.searchView
+                    this, this, db, localAccount.getId(), canMoveNoteToAnotherAccounts, adapter, listView, this::refreshLists, getSupportFragmentManager(), activityBinding.searchView
             ));
             int checkedItemCount = adapter.getSelected().size();
             mActionMode.setTitle(getResources().getQuantityString(R.plurals.ab_selected, checkedItemCount, checkedItemCount));
@@ -922,7 +922,7 @@ public class MainActivity extends LockedActivity implements NoteClickListener, V
     }
 
     private void synchronize() {
-        NoteServerSyncHelper syncHelper = roomDatabase.getNoteServerSyncHelper();
+        NoteServerSyncHelper syncHelper = db.getNoteServerSyncHelper();
         if (!syncHelper.isSyncPossible()) {
             syncHelper.updateNetworkStatus();
         }
@@ -954,9 +954,9 @@ public class MainActivity extends LockedActivity implements NoteClickListener, V
 
     @Override
     public void onAccountDeleted(LocalAccountEntity localAccount) {
-        roomDatabase.deleteAccount(localAccount);
+        db.deleteAccount(localAccount);
         if (localAccount.getId() == this.localAccount.getId()) {
-            List<LocalAccountEntity> remainingAccounts = roomDatabase.getLocalAccountDao().getAccounts();
+            List<LocalAccountEntity> remainingAccounts = db.getLocalAccountDao().getAccounts();
             if (remainingAccounts.size() > 0) {
                 this.localAccount = remainingAccounts.get(0);
                 selectAccount(this.localAccount.getAccountName());
@@ -974,7 +974,7 @@ public class MainActivity extends LockedActivity implements NoteClickListener, V
         adapter.deselect(0);
         for (Integer i : selection) {
             NoteEntity note = (NoteEntity) adapter.getItem(i);
-            roomDatabase.moveNoteToAnotherAccount(ssoAccount, note.getAccountId(), roomDatabase.getNoteDao().getNote(note.getAccountId(), note.getId()), account.getId());
+            db.moveNoteToAnotherAccount(ssoAccount, note.getAccountId(), db.getNoteDao().getNote(note.getAccountId(), note.getId()), account.getId());
             RecyclerView.ViewHolder viewHolder = listView.findViewHolderForAdapterPosition(i);
             if (viewHolder != null) {
                 viewHolder.itemView.setSelected(false);
@@ -994,7 +994,7 @@ public class MainActivity extends LockedActivity implements NoteClickListener, V
             CategoryEntity c = new CategoryEntity();
             c.setTitle(category);
             note.setCategory(c);
-            roomDatabase.setCategory(ssoAccount, note, category, this::refreshLists);
+            db.setCategory(ssoAccount, note, category, this::refreshLists);
         }
 
         mActionMode.finish();
diff --git a/app/src/main/java/it/niedermann/owncloud/notes/main/items/list/NotesListViewItemTouchHelper.java b/app/src/main/java/it/niedermann/owncloud/notes/main/items/list/NotesListViewItemTouchHelper.java
index 864d1313..fcf9e248 100644
--- a/app/src/main/java/it/niedermann/owncloud/notes/main/items/list/NotesListViewItemTouchHelper.java
+++ b/app/src/main/java/it/niedermann/owncloud/notes/main/items/list/NotesListViewItemTouchHelper.java
@@ -33,7 +33,7 @@ public class NotesListViewItemTouchHelper extends ItemTouchHelper {
     public NotesListViewItemTouchHelper(
             @NonNull SingleSignOnAccount ssoAccount,
             @NonNull Context context,
-            @NonNull NotesRoomDatabase roomDatabase,
+            @NonNull NotesRoomDatabase db,
             @NonNull ItemAdapter adapter,
             @NonNull ISyncCallback syncCallBack,
             @NonNull Runnable refreshLists,
@@ -72,8 +72,8 @@ public class NotesListViewItemTouchHelper extends ItemTouchHelper {
                 switch (direction) {
                     case ItemTouchHelper.LEFT:
                         final NoteEntity dbNoteWithoutContent = (NoteEntity) adapter.getItem(viewHolder.getAdapterPosition());
-                        final NoteEntity dbNote = roomDatabase.getNoteDao().getNote(dbNoteWithoutContent.getAccountId(), dbNoteWithoutContent.getId());
-                        roomDatabase.deleteNoteAndSync(ssoAccount, dbNote.getId());
+                        final NoteEntity dbNote = db.getNoteDao().getNote(dbNoteWithoutContent.getAccountId(), dbNoteWithoutContent.getId());
+                        db.deleteNoteAndSync(ssoAccount, dbNote.getId());
                         adapter.remove(dbNote);
                         refreshLists.run();
                         Log.v(TAG, "Item deleted through swipe ----------------------------------------------");
@@ -82,8 +82,8 @@ public class NotesListViewItemTouchHelper extends ItemTouchHelper {
                         } else {
                             BrandedSnackbar.make(viewProvider.getView(), context.getString(R.string.action_note_deleted, dbNote.getTitle()), UNDO_DURATION)
                                     .setAction(R.string.action_undo, (View v) -> {
-                                        roomDatabase.getNoteServerSyncHelper().addCallbackPush(ssoAccount, refreshLists::run);
-                                        roomDatabase.addNoteAndSync(ssoAccount, dbNote.getAccountId(), dbNote);
+                                        db.getNoteServerSyncHelper().addCallbackPush(ssoAccount, refreshLists::run);
+                                        db.addNoteAndSync(ssoAccount, dbNote.getAccountId(), dbNote);
                                         refreshLists.run();
                                         BrandedSnackbar.make(viewProvider.getView(), context.getString(R.string.action_note_restored, dbNote.getTitle()), Snackbar.LENGTH_SHORT)
                                                 .show();
@@ -93,7 +93,7 @@ public class NotesListViewItemTouchHelper extends ItemTouchHelper {
                         break;
                     case ItemTouchHelper.RIGHT:
                         final NoteEntity adapterNote = (NoteEntity) adapter.getItem(viewHolder.getAdapterPosition());
-                        roomDatabase.toggleFavoriteAndSync(ssoAccount, adapterNote.getId(), syncCallBack);
+                        db.toggleFavoriteAndSync(ssoAccount, adapterNote.getId(), syncCallBack);
                         refreshLists.run();
                         break;
                     default:
diff --git a/app/src/main/java/it/niedermann/owncloud/notes/manageaccounts/ManageAccountsActivity.java b/app/src/main/java/it/niedermann/owncloud/notes/manageaccounts/ManageAccountsActivity.java
index ae5d2165..8cf0d51d 100644
--- a/app/src/main/java/it/niedermann/owncloud/notes/manageaccounts/ManageAccountsActivity.java
+++ b/app/src/main/java/it/niedermann/owncloud/notes/manageaccounts/ManageAccountsActivity.java
@@ -21,7 +21,7 @@ public class ManageAccountsActivity extends LockedActivity {
 
     private ActivityManageAccountsBinding binding;
     private ManageAccountAdapter adapter;
-    private NotesRoomDatabase roomDatabase = null;
+    private NotesRoomDatabase db = null;
 
     @Override
     public void onCreate(@Nullable Bundle savedInstanceState) {
@@ -32,12 +32,12 @@ public class ManageAccountsActivity extends LockedActivity {
 
         setSupportActionBar(binding.toolbar);
 
-        roomDatabase = NotesRoomDatabase.getInstance(this);
+        db = NotesRoomDatabase.getInstance(this);
 
-        List<LocalAccountEntity> localAccounts = roomDatabase.getLocalAccountDao().getAccounts();
+        List<LocalAccountEntity> localAccounts = db.getLocalAccountDao().getAccounts();
 
         adapter = new ManageAccountAdapter((localAccount) -> SingleAccountHelper.setCurrentAccount(getApplicationContext(), localAccount.getAccountName()), (localAccount) -> {
-            roomDatabase.deleteAccount(localAccount);
+            db.deleteAccount(localAccount);
             for (LocalAccountEntity temp : localAccounts) {
                 if (temp.getId() == localAccount.getId()) {
                     localAccounts.remove(temp);
@@ -56,7 +56,7 @@ public class ManageAccountsActivity extends LockedActivity {
         try {
             SingleSignOnAccount ssoAccount = SingleAccountHelper.getCurrentSingleSignOnAccount(this);
             if (ssoAccount != null) {
-                adapter.setCurrentLocalAccount(roomDatabase.getLocalAccountDao().getLocalAccountByAccountName(ssoAccount.name));
+                adapter.setCurrentLocalAccount(db.getLocalAccountDao().getLocalAccountByAccountName(ssoAccount.name));
             }
         } catch (NextcloudFilesAppAccountNotFoundException | NoCurrentAccountSelectedException e) {
             e.printStackTrace();
diff --git a/app/src/main/java/it/niedermann/owncloud/notes/persistence/LoadNotesListTask.java b/app/src/main/java/it/niedermann/owncloud/notes/persistence/LoadNotesListTask.java
index 62f5d66c..676fad9f 100644
--- a/app/src/main/java/it/niedermann/owncloud/notes/persistence/LoadNotesListTask.java
+++ b/app/src/main/java/it/niedermann/owncloud/notes/persistence/LoadNotesListTask.java
@@ -39,9 +39,9 @@ public class LoadNotesListTask extends AsyncTask<Void, Void, List<Item>> {
     @Override
     protected List<Item> doInBackground(Void... voids) {
         List<NoteEntity> noteList;
-        NotesRoomDatabase roomDatabase = NotesRoomDatabase.getInstance(context);
-        CategorySortingMethod sortingMethod = roomDatabase.getCategoryOrder(accountId, category);
-        noteList = roomDatabase.getNoteDao().searchNotesSubcategory(accountId, searchQuery.toString(), category.category, category.favorite, sortingMethod);
+        NotesRoomDatabase db = NotesRoomDatabase.getInstance(context);
+        CategorySortingMethod sortingMethod = db.getCategoryOrder(accountId, category);
+        noteList = db.getNoteDao().searchNotesSubcategory(accountId, searchQuery.toString(), category.category, category.favorite, sortingMethod);
 
         if (category.category == null) {
             if (sortingMethod == CategorySortingMethod.SORT_MODIFIED_DESC) {
diff --git a/app/src/main/java/it/niedermann/owncloud/notes/persistence/NoteServerSyncHelper.java b/app/src/main/java/it/niedermann/owncloud/notes/persistence/NoteServerSyncHelper.java
index 362fdf44..bf6c906d 100644
--- a/app/src/main/java/it/niedermann/owncloud/notes/persistence/NoteServerSyncHelper.java
+++ b/app/src/main/java/it/niedermann/owncloud/notes/persistence/NoteServerSyncHelper.java
@@ -118,12 +118,12 @@ public class NoteServerSyncHelper {
      * This has to be a singleton in order to realize correct registering and unregistering of
      * the BroadcastReceiver, which listens on changes of network connectivity.
      *
-     * @param roomDatabase {@link NotesRoomDatabase}
+     * @param db {@link NotesRoomDatabase}
      * @return NoteServerSyncHelper
      */
-    public static synchronized NoteServerSyncHelper getInstance(NotesRoomDatabase roomDatabase) {
+    public static synchronized NoteServerSyncHelper getInstance(NotesRoomDatabase db) {
         if (instance == null) {
-            instance = new NoteServerSyncHelper(roomDatabase);
+            instance = new NoteServerSyncHelper(db);
         }
         return instance;
     }
diff --git a/app/src/main/java/it/niedermann/owncloud/notes/widget/notelist/NoteListWidget.java b/app/src/main/java/it/niedermann/owncloud/notes/widget/notelist/NoteListWidget.java
index 51a589c0..80edb446 100644
--- a/app/src/main/java/it/niedermann/owncloud/notes/widget/notelist/NoteListWidget.java
+++ b/app/src/main/java/it/niedermann/owncloud/notes/widget/notelist/NoteListWidget.java
@@ -36,19 +36,19 @@ public class NoteListWidget extends AppWidgetProvider {
     public static final int PENDING_INTENT_OPEN_APP_RQ = 2;
 
     static void updateAppWidget(Context context, AppWidgetManager awm, int[] appWidgetIds) {
-        final NotesRoomDatabase roomDatabase = NotesRoomDatabase.getInstance(context);
+        final NotesRoomDatabase db = NotesRoomDatabase.getInstance(context);
 
         RemoteViews views;
         DarkModeSetting darkTheme;
 
         for (int appWidgetId : appWidgetIds) {
             try {
-                final NoteListsWidgetData data = roomDatabase.getWidgetNotesListDao().getNoteListWidgetData(appWidgetId);
-                final LocalAccountEntity localAccountEntity = roomDatabase.getLocalAccountDao().getAccount(data.getAccountId());
+                final NoteListsWidgetData data = db.getWidgetNotesListDao().getNoteListWidgetData(appWidgetId);
+                final LocalAccountEntity localAccountEntity = db.getLocalAccountDao().getAccount(data.getAccountId());
 
                 String category = null;
                 if (data.getCategoryId() != null) {
-                    category = roomDatabase.getCategoryDao().getCategoryTitleById(data.getCategoryId());
+                    category = db.getCategoryDao().getCategoryTitleById(data.getCategoryId());
                 }
 
                 darkTheme = DarkModeSetting.fromModeID(data.getThemeMode());
diff --git a/app/src/main/java/it/niedermann/owncloud/notes/widget/notelist/NoteListWidgetConfigurationActivity.java b/app/src/main/java/it/niedermann/owncloud/notes/widget/notelist/NoteListWidgetConfigurationActivity.java
index cdcb6d0c..10ac43fc 100644
--- a/app/src/main/java/it/niedermann/owncloud/notes/widget/notelist/NoteListWidgetConfigurationActivity.java
+++ b/app/src/main/java/it/niedermann/owncloud/notes/widget/notelist/NoteListWidgetConfigurationActivity.java
@@ -40,7 +40,7 @@ public class NoteListWidgetConfigurationActivity extends LockedActivity {
     private NavigationAdapter adapterCategories;
     private NavigationAdapter.NavigationItem itemRecent;
     private NavigationAdapter.NavigationItem itemFavorites;
-    private NotesRoomDatabase roomDatabase = null;
+    private NotesRoomDatabase db = null;
 
     @Override
     protected void onCreate(@Nullable Bundle savedInstanceState) {
@@ -48,9 +48,9 @@ public class NoteListWidgetConfigurationActivity extends LockedActivity {
         setResult(RESULT_CANCELED);
         setContentView(R.layout.activity_note_list_configuration);
 
-        roomDatabase = NotesRoomDatabase.getInstance(this);
+        db = NotesRoomDatabase.getInstance(this);
         try {
-            this.localAccount = roomDatabase.getLocalAccountDao().getLocalAccountByAccountName(SingleAccountHelper.getCurrentSingleSignOnAccount(this).name);
+            this.localAccount = db.getLocalAccountDao().getLocalAccountByAccountName(SingleAccountHelper.getCurrentSingleSignOnAccount(this).name);
         } catch (NextcloudFilesAppAccountNotFoundException | NoCurrentAccountSelectedException e) {
             e.printStackTrace();
             Toast.makeText(this, R.string.widget_not_logged_in, Toast.LENGTH_LONG).show();
@@ -104,7 +104,7 @@ public class NoteListWidgetConfigurationActivity extends LockedActivity {
                 data.setAccountId(localAccount.getId());
                 data.setThemeMode(NotesApplication.getAppTheme(getApplicationContext()).getModeId());
 
-                roomDatabase.getWidgetNotesListDao().createOrUpdateNoteListWidgetData(data);
+                db.getWidgetNotesListDao().createOrUpdateNoteListWidgetData(data);
 
                 Intent updateIntent = new Intent(AppWidgetManager.ACTION_APPWIDGET_UPDATE, null,
                         getApplicationContext(), NoteListWidget.class);
@@ -143,7 +143,7 @@ public class NoteListWidgetConfigurationActivity extends LockedActivity {
                 return new ArrayList<>();
             }
             NavigationAdapter.NavigationItem itemUncategorized;
-            List<CategoryNavigationItem> categories = roomDatabase.getCategories(localAccount.getId());
+            List<CategoryNavigationItem> categories = db.getCategories(localAccount.getId());
 
             if (!categories.isEmpty() && categories.get(0).label.isEmpty()) {
                 itemUncategorized = categories.get(0);
@@ -151,8 +151,8 @@ public class NoteListWidgetConfigurationActivity extends LockedActivity {
                 itemUncategorized.icon = NavigationAdapter.ICON_NOFOLDER;
             }
 
-            int numFavorites = roomDatabase.getNoteDao().getFavoritesCount(localAccount.getId());
-            int numNonFavorites = roomDatabase.getNoteDao().getNonFavoritesCount(localAccount.getId());
+            int numFavorites = db.getNoteDao().getFavoritesCount(localAccount.getId());
+            int numNonFavorites = db.getNoteDao().getNonFavoritesCount(localAccount.getId());
             itemFavorites.count = numFavorites;
             itemRecent.count = numFavorites + numNonFavorites;
 
diff --git a/app/src/main/java/it/niedermann/owncloud/notes/widget/singlenote/SingleNoteWidget.java b/app/src/main/java/it/niedermann/owncloud/notes/widget/singlenote/SingleNoteWidget.java
index 7ecec33a..b2c46c8a 100644
--- a/app/src/main/java/it/niedermann/owncloud/notes/widget/singlenote/SingleNoteWidget.java
+++ b/app/src/main/java/it/niedermann/owncloud/notes/widget/singlenote/SingleNoteWidget.java
@@ -80,10 +80,10 @@ public class SingleNoteWidget extends AppWidgetProvider {
 
     @Override
     public void onDeleted(Context context, int[] appWidgetIds) {
-        final NotesRoomDatabase roomDatabase = NotesRoomDatabase.getInstance(context);
+        final NotesRoomDatabase db = NotesRoomDatabase.getInstance(context);
 
         for (int appWidgetId : appWidgetIds) {
-            roomDatabase.getWidgetSingleNoteDao().removeSingleNoteWidget(appWidgetId);
+            db.getWidgetSingleNoteDao().removeSingleNoteWidget(appWidgetId);
         }
         super.onDeleted(context, appWidgetIds);
     }
diff --git a/app/src/main/java/it/niedermann/owncloud/notes/widget/singlenote/SingleNoteWidgetConfigurationActivity.java b/app/src/main/java/it/niedermann/owncloud/notes/widget/singlenote/SingleNoteWidgetConfigurationActivity.java
index 555a9d87..60c6fb44 100644
--- a/app/src/main/java/it/niedermann/owncloud/notes/widget/singlenote/SingleNoteWidgetConfigurationActivity.java
+++ b/app/src/main/java/it/niedermann/owncloud/notes/widget/singlenote/SingleNoteWidgetConfigurationActivity.java
@@ -53,7 +53,7 @@ public class SingleNoteWidgetConfigurationActivity extends MainActivity {
         int appWidgetId = extras.getInt(AppWidgetManager.EXTRA_APPWIDGET_ID, AppWidgetManager.INVALID_APPWIDGET_ID);
 
         try {
-            roomDatabase.getWidgetSingleNoteDao().createOrUpdateSingleNoteWidgetData(
+            db.getWidgetSingleNoteDao().createOrUpdateSingleNoteWidgetData(
                     new WidgetSingleNoteEntity(
                             appWidgetId,
                             note.getAccountId(),