Fix #750 Split up NoteSQLiteOpenHelper

Signed-off-by: stefan-niedermann <info@niedermann.it>

app/src/main/java/it/niedermann/owncloud/notes/android/MultiSelectedActionModeCallback.java

@@ -25,14 +25,14 @@ import it.niedermann.owncloud.notes.android.activity.NotesListViewActivity;
 import it.niedermann.owncloud.notes.android.fragment.AccountChooserDialogFragment;
 import it.niedermann.owncloud.notes.model.DBNote;
 import it.niedermann.owncloud.notes.model.ItemAdapter;
-import it.niedermann.owncloud.notes.persistence.NoteSQLiteOpenHelper;
+import it.niedermann.owncloud.notes.persistence.NotesDatabase;
 import it.niedermann.owncloud.notes.persistence.NoteServerSyncHelper.ViewProvider;
 
 public class MultiSelectedActionModeCallback implements Callback {
 
     private final Context context;
     private final ViewProvider viewProvider;
-    private final NoteSQLiteOpenHelper db;
+    private final NotesDatabase db;
     private final ItemAdapter adapter;
     private final RecyclerView recyclerView;
     private final Runnable refreshLists;
@@ -40,7 +40,7 @@ public class MultiSelectedActionModeCallback implements Callback {
     private final SearchView searchView;
 
     public MultiSelectedActionModeCallback(
-            Context context, ViewProvider viewProvider, NoteSQLiteOpenHelper db, ActionMode actionMode, ItemAdapter adapter, RecyclerView recyclerView, Runnable refreshLists, FragmentManager fragmentManager, SearchView searchView) {
+            Context context, ViewProvider viewProvider, NotesDatabase db, ActionMode actionMode, ItemAdapter adapter, RecyclerView recyclerView, Runnable refreshLists, FragmentManager fragmentManager, SearchView searchView) {
         this.context = context;
         this.viewProvider = viewProvider;
         this.db = db;

app/src/main/java/it/niedermann/owncloud/notes/android/NotesListViewItemTouchHelper.java

@@ -16,7 +16,7 @@ import it.niedermann.owncloud.notes.R;
 import it.niedermann.owncloud.notes.model.DBNote;
 import it.niedermann.owncloud.notes.model.ISyncCallback;
 import it.niedermann.owncloud.notes.model.ItemAdapter;
-import it.niedermann.owncloud.notes.persistence.NoteSQLiteOpenHelper;
+import it.niedermann.owncloud.notes.persistence.NotesDatabase;
 import it.niedermann.owncloud.notes.persistence.NoteServerSyncHelper.ViewProvider;
 
 public class NotesListViewItemTouchHelper extends ItemTouchHelper {
@@ -27,7 +27,7 @@ public class NotesListViewItemTouchHelper extends ItemTouchHelper {
             SingleSignOnAccount ssoAccount,
             Context context,
             ViewProvider viewProvider,
-            NoteSQLiteOpenHelper db,
+            NotesDatabase db,
             ItemAdapter adapter,
             ISyncCallback syncCallBack,
             Runnable refreshLists

app/src/main/java/it/niedermann/owncloud/notes/android/activity/NotesListViewActivity.java

@@ -67,7 +67,7 @@ import it.niedermann.owncloud.notes.model.NavigationAdapter;
 import it.niedermann.owncloud.notes.model.NavigationAdapter.NavigationItem;
 import it.niedermann.owncloud.notes.persistence.LoadNotesListTask;
 import it.niedermann.owncloud.notes.persistence.LoadNotesListTask.NotesLoadedListener;
-import it.niedermann.owncloud.notes.persistence.NoteSQLiteOpenHelper;
+import it.niedermann.owncloud.notes.persistence.NotesDatabase;
 import it.niedermann.owncloud.notes.persistence.NoteServerSyncHelper;
 import it.niedermann.owncloud.notes.util.NoteUtil;
 
@@ -140,7 +140,7 @@ public class NotesListViewActivity extends AppCompatActivity implements ItemAdap
     private Category navigationSelection = new Category(null, null);
     private String navigationOpen = "";
     private ActionMode mActionMode;
-    private NoteSQLiteOpenHelper db = null;
+    private NotesDatabase db = null;
     private SearchView searchView = null;
     private final ISyncCallback syncCallBack = () -> {
         adapter.clearSelection(listView);
@@ -174,7 +174,7 @@ public class NotesListViewActivity extends AppCompatActivity implements ItemAdap
             categoryAdapterSelectedItem = savedInstanceState.getString(SAVED_STATE_NAVIGATION_ADAPTER_SLECTION);
         }
 
-        db = NoteSQLiteOpenHelper.getInstance(this);
+        db = NotesDatabase.getInstance(this);
 
         setupHeader();
         setupActionBar();
@@ -770,7 +770,7 @@ public class NotesListViewActivity extends AppCompatActivity implements ItemAdap
     @Override
     public void onNoteFavoriteClick(int position, View view) {
         DBNote note = (DBNote) adapter.getItem(position);
-        NoteSQLiteOpenHelper db = NoteSQLiteOpenHelper.getInstance(view.getContext());
+        NotesDatabase db = NotesDatabase.getInstance(view.getContext());
         db.toggleFavorite(ssoAccount, note, syncCallBack);
         adapter.notifyItemChanged(position);
         refreshLists();

app/src/main/java/it/niedermann/owncloud/notes/android/appwidget/NoteListWidgetConfiguration.java

@@ -27,7 +27,7 @@ import it.niedermann.owncloud.notes.R;
 import it.niedermann.owncloud.notes.android.activity.NotesListViewActivity;
 import it.niedermann.owncloud.notes.model.LocalAccount;
 import it.niedermann.owncloud.notes.model.NavigationAdapter;
-import it.niedermann.owncloud.notes.persistence.NoteSQLiteOpenHelper;
+import it.niedermann.owncloud.notes.persistence.NotesDatabase;
 import it.niedermann.owncloud.notes.util.Notes;
 
 public class NoteListWidgetConfiguration extends AppCompatActivity {
@@ -40,7 +40,7 @@ public class NoteListWidgetConfiguration extends AppCompatActivity {
 
     private NavigationAdapter adapterCategories;
     private NavigationAdapter.NavigationItem itemRecent, itemFavorites;
-    private NoteSQLiteOpenHelper db = null;
+    private NotesDatabase db = null;
 
     @Override
     protected void onCreate(@Nullable Bundle savedInstanceState) {
@@ -48,7 +48,7 @@ public class NoteListWidgetConfiguration extends AppCompatActivity {
         setResult(RESULT_CANCELED);
         setContentView(R.layout.activity_note_list_configuration);
 
-        db = NoteSQLiteOpenHelper.getInstance(this);
+        db = NotesDatabase.getInstance(this);
         try {
             this.localAccount = db.getLocalAccountByAccountName(SingleAccountHelper.getCurrentSingleSignOnAccount(this).name);
         } catch (NextcloudFilesAppAccountNotFoundException | NoCurrentAccountSelectedException e) {

app/src/main/java/it/niedermann/owncloud/notes/android/appwidget/NoteListWidgetFactory.java

@@ -15,7 +15,7 @@ import java.util.List;
 import it.niedermann.owncloud.notes.R;
 import it.niedermann.owncloud.notes.android.activity.EditNoteActivity;
 import it.niedermann.owncloud.notes.model.DBNote;
-import it.niedermann.owncloud.notes.persistence.NoteSQLiteOpenHelper;
+import it.niedermann.owncloud.notes.persistence.NotesDatabase;
 
 public class NoteListWidgetFactory implements RemoteViewsService.RemoteViewsFactory {
     private final Context context;
@@ -23,7 +23,7 @@ public class NoteListWidgetFactory implements RemoteViewsService.RemoteViewsFact
     private final boolean darkTheme;
     private final String category;
     private final long accountId;
-    private NoteSQLiteOpenHelper db;
+    private NotesDatabase db;
     private List<DBNote> dbNotes;
 
     NoteListWidgetFactory(Context context, Intent intent) {
@@ -39,7 +39,7 @@ public class NoteListWidgetFactory implements RemoteViewsService.RemoteViewsFact
 
     @Override
     public void onCreate() {
-        db = NoteSQLiteOpenHelper.getInstance(context);
+        db = NotesDatabase.getInstance(context);
     }
 
     @Override

app/src/main/java/it/niedermann/owncloud/notes/android/appwidget/SingleNoteWidgetFactory.java

@@ -16,7 +16,7 @@ import com.yydcdut.markdown.syntax.text.TextFactory;
 import it.niedermann.owncloud.notes.R;
 import it.niedermann.owncloud.notes.android.activity.EditNoteActivity;
 import it.niedermann.owncloud.notes.model.DBNote;
-import it.niedermann.owncloud.notes.persistence.NoteSQLiteOpenHelper;
+import it.niedermann.owncloud.notes.persistence.NotesDatabase;
 import it.niedermann.owncloud.notes.util.MarkDownUtil;
 
 public class SingleNoteWidgetFactory implements RemoteViewsService.RemoteViewsFactory {
@@ -25,7 +25,7 @@ public class SingleNoteWidgetFactory implements RemoteViewsService.RemoteViewsFa
     private final Context context;
     private final int appWidgetId;
 
-    private NoteSQLiteOpenHelper db;
+    private NotesDatabase db;
     private DBNote note;
     private final SharedPreferences sp;
     private static Boolean darkTheme;
@@ -45,7 +45,7 @@ public class SingleNoteWidgetFactory implements RemoteViewsService.RemoteViewsFa
 
     @Override
     public void onCreate() {
-        db = NoteSQLiteOpenHelper.getInstance(context);
+        db = NotesDatabase.getInstance(context);
     }
 
 

app/src/main/java/it/niedermann/owncloud/notes/android/fragment/AccountChooserDialogFragment.java

@@ -22,7 +22,7 @@ import butterknife.ButterKnife;
 import it.niedermann.owncloud.notes.R;
 import it.niedermann.owncloud.notes.android.fragment.AccountChooserAdapter.AccountChooserListener;
 import it.niedermann.owncloud.notes.model.LocalAccount;
-import it.niedermann.owncloud.notes.persistence.NoteSQLiteOpenHelper;
+import it.niedermann.owncloud.notes.persistence.NotesDatabase;
 
 public class AccountChooserDialogFragment extends AppCompatDialogFragment implements AccountChooserListener {
     private AccountChooserListener accountChooserListener;
@@ -51,7 +51,7 @@ public class AccountChooserDialogFragment extends AppCompatDialogFragment implem
         View view = View.inflate(getContext(), R.layout.dialog_choose_account, null);
         ButterKnife.bind(this, view);
 
-        NoteSQLiteOpenHelper db = NoteSQLiteOpenHelper.getInstance(getActivity());
+        NotesDatabase db = NotesDatabase.getInstance(getActivity());
         List<LocalAccount> accountsList = db.getAccounts();
 
         RecyclerView.Adapter adapter = new AccountChooserAdapter(accountsList, this, requireActivity());

app/src/main/java/it/niedermann/owncloud/notes/android/fragment/BaseNoteFragment.java

@@ -34,7 +34,7 @@ import it.niedermann.owncloud.notes.model.DBNote;
 import it.niedermann.owncloud.notes.model.DBStatus;
 import it.niedermann.owncloud.notes.model.ISyncCallback;
 import it.niedermann.owncloud.notes.model.LocalAccount;
-import it.niedermann.owncloud.notes.persistence.NoteSQLiteOpenHelper;
+import it.niedermann.owncloud.notes.persistence.NotesDatabase;
 import it.niedermann.owncloud.notes.util.NoteUtil;
 
 import static androidx.core.content.pm.ShortcutManagerCompat.isRequestPinShortcutSupported;
@@ -58,7 +58,7 @@ public abstract class BaseNoteFragment extends Fragment implements CategoryDialo
     protected DBNote note;
     @Nullable
     private DBNote originalNote;
-    protected NoteSQLiteOpenHelper db;
+    protected NotesDatabase db;
     private NoteFragmentListener listener;
 
     boolean isNew = true;
@@ -113,7 +113,7 @@ public abstract class BaseNoteFragment extends Fragment implements CategoryDialo
         } catch (ClassCastException e) {
             throw new ClassCastException(context.getClass() + " must implement " + NoteFragmentListener.class);
         }
-        db = NoteSQLiteOpenHelper.getInstance(context);
+        db = NotesDatabase.getInstance(context);
     }
 
     @Override

app/src/main/java/it/niedermann/owncloud/notes/android/fragment/CategoryDialogFragment.java

@@ -24,7 +24,7 @@ import butterknife.BindView;
 import butterknife.ButterKnife;
 import it.niedermann.owncloud.notes.R;
 import it.niedermann.owncloud.notes.model.NavigationAdapter;
-import it.niedermann.owncloud.notes.persistence.NoteSQLiteOpenHelper;
+import it.niedermann.owncloud.notes.persistence.NotesDatabase;
 
 /**
  * This {@link DialogFragment} allows for the selection of a category.
@@ -36,7 +36,7 @@ public class CategoryDialogFragment extends AppCompatDialogFragment {
     private static final String TAG = CategoryDialogFragment.class.getSimpleName();
     private static final String STATE_CATEGORY = "category";
 
-    private NoteSQLiteOpenHelper db;
+    private NotesDatabase db;
     private CategoryDialogListener listener;
 
     /**
@@ -80,7 +80,7 @@ public class CategoryDialogFragment extends AppCompatDialogFragment {
         } else {
             throw new IllegalArgumentException("Calling activity or target fragment must implement " + CategoryDialogListener.class.getCanonicalName());
         }
-        db = NoteSQLiteOpenHelper.getInstance(getActivity());
+        db = NotesDatabase.getInstance(getActivity());
     }
 
     @NonNull

app/src/main/java/it/niedermann/owncloud/notes/android/fragment/NotePreviewFragment.java

@@ -39,7 +39,7 @@ import butterknife.ButterKnife;
 import it.niedermann.owncloud.notes.R;
 import it.niedermann.owncloud.notes.android.activity.EditNoteActivity;
 import it.niedermann.owncloud.notes.model.LoginStatus;
-import it.niedermann.owncloud.notes.persistence.NoteSQLiteOpenHelper;
+import it.niedermann.owncloud.notes.persistence.NotesDatabase;
 import it.niedermann.owncloud.notes.util.DisplayUtils;
 import it.niedermann.owncloud.notes.util.MarkDownUtil;
 import it.niedermann.owncloud.notes.util.NoteLinksUtils;
@@ -188,7 +188,7 @@ public class NotePreviewFragment extends SearchableBaseNoteFragment implements O
         changedText = note.getContent();
         noteContent.setMovementMethod(LinkMovementMethod.getInstance());
 
-        db = NoteSQLiteOpenHelper.getInstance(getContext());
+        db = NotesDatabase.getInstance(getContext());
         swipeRefreshLayout.setOnRefreshListener(this);
 
         SharedPreferences sp = PreferenceManager.getDefaultSharedPreferences(requireActivity().getApplicationContext());

app/src/main/java/it/niedermann/owncloud/notes/android/fragment/NoteReadonlyFragment.java

@@ -33,7 +33,7 @@ import butterknife.ButterKnife;
 import it.niedermann.owncloud.notes.R;
 import it.niedermann.owncloud.notes.android.activity.EditNoteActivity;
 import it.niedermann.owncloud.notes.model.ISyncCallback;
-import it.niedermann.owncloud.notes.persistence.NoteSQLiteOpenHelper;
+import it.niedermann.owncloud.notes.persistence.NotesDatabase;
 import it.niedermann.owncloud.notes.util.DisplayUtils;
 import it.niedermann.owncloud.notes.util.MarkDownUtil;
 import it.niedermann.owncloud.notes.util.NoteLinksUtils;
@@ -139,7 +139,7 @@ public class NoteReadonlyFragment extends SearchableBaseNoteFragment {
         }
         noteContent.setMovementMethod(LinkMovementMethod.getInstance());
 
-        db = NoteSQLiteOpenHelper.getInstance(getActivity());
+        db = NotesDatabase.getInstance(getActivity());
         swipeRefreshLayout.setEnabled(false);
 
         SharedPreferences sp = PreferenceManager.getDefaultSharedPreferences(requireActivity().getApplicationContext());

app/src/main/java/it/niedermann/owncloud/notes/persistence/AbstractNotesDatabase.java

@@ -0,0 +1,271 @@
+package it.niedermann.owncloud.notes.persistence;
+
+import android.appwidget.AppWidgetManager;
+import android.content.ComponentName;
+import android.content.ContentValues;
+import android.content.Context;
+import android.content.SharedPreferences;
+import android.database.Cursor;
+import android.database.sqlite.SQLiteDatabase;
+import android.database.sqlite.SQLiteOpenHelper;
+import android.preference.PreferenceManager;
+import android.util.Log;
+
+import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
+
+import java.net.MalformedURLException;
+import java.net.URL;
+
+import it.niedermann.owncloud.notes.android.appwidget.NoteListWidget;
+import it.niedermann.owncloud.notes.android.appwidget.SingleNoteWidget;
+import it.niedermann.owncloud.notes.model.DBStatus;
+import it.niedermann.owncloud.notes.util.DatabaseIndexUtil;
+import it.niedermann.owncloud.notes.util.NoteUtil;
+
+// Protected APIs
+@SuppressWarnings("WeakerAccess")
+abstract class AbstractNotesDatabase extends SQLiteOpenHelper {
+
+    private static final String TAG = AbstractNotesDatabase.class.getSimpleName();
+
+    private static final int database_version = 10;
+    private final Context context;
+
+    protected static final String database_name = "OWNCLOUD_NOTES";
+    protected static final String table_notes = "NOTES";
+    protected static final String table_accounts = "ACCOUNTS";
+
+    protected static final String key_id = "ID";
+
+    protected static final String key_url = "URL";
+    protected static final String key_account_name = "ACCOUNT_NAME";
+    protected static final String key_username = "USERNAME";
+
+    protected static final String key_account_id = "ACCOUNT_ID";
+    protected static final String key_remote_id = "REMOTEID";
+    protected static final String key_status = "STATUS";
+    protected static final String key_title = "TITLE";
+    protected static final String key_modified = "MODIFIED";
+    protected static final String key_content = "CONTENT";
+    protected static final String key_excerpt = "EXCERPT";
+    protected static final String key_favorite = "FAVORITE";
+    protected static final String key_category = "CATEGORY";
+    protected static final String key_etag = "ETAG";
+
+    protected AbstractNotesDatabase(@Nullable Context context, @Nullable String name, @Nullable SQLiteDatabase.CursorFactory factory) {
+        super(context, name, factory, database_version);
+        this.context = context;
+    }
+
+
+    public Context getContext() {
+        return context;
+    }
+
+    /**
+     * Creates initial the Database
+     *
+     * @param db Database
+     */
+    @Override
+    public void onCreate(SQLiteDatabase db) {
+        createAccountTable(db);
+        createNotesTable(db);
+    }
+
+    private void createNotesTable(@NonNull SQLiteDatabase db) {
+        db.execSQL("CREATE TABLE " + table_notes + " ( " +
+                key_id + " INTEGER PRIMARY KEY AUTOINCREMENT, " +
+                key_remote_id + " INTEGER, " +
+                key_account_id + " INTEGER, " +
+                key_status + " VARCHAR(50), " +
+                key_title + " TEXT, " +
+                key_modified + " INTEGER DEFAULT 0, " +
+                key_content + " TEXT, " +
+                key_favorite + " INTEGER DEFAULT 0, " +
+                key_category + " TEXT NOT NULL DEFAULT '', " +
+                key_etag + " TEXT," +
+                key_excerpt + " TEXT NOT NULL DEFAULT '', " +
+                "FOREIGN KEY(" + key_account_id + ") REFERENCES " + table_accounts + "(" + key_id + "))");
+        createNotesIndexes(db);
+    }
+
+    private void createAccountTable(@NonNull SQLiteDatabase db) {
+        db.execSQL("CREATE TABLE " + table_accounts + " ( " +
+                key_id + " INTEGER PRIMARY KEY AUTOINCREMENT, " +
+                key_url + " TEXT, " +
+                key_username + " TEXT, " +
+                key_account_name + " TEXT UNIQUE, " +
+                key_etag + " TEXT, " +
+                key_modified + " INTEGER)");
+        createAccountIndexes(db);
+    }
+
+    @SuppressWarnings("deprecation")
+    @Override
+    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
+        if (oldVersion < 3) {
+            recreateDatabase(db);
+            return;
+        }
+        if (oldVersion < 4) {
+            db.delete(table_notes, null, null);
+            db.delete(table_accounts, null, null);
+        }
+        if (oldVersion < 5) {
+            db.execSQL("ALTER TABLE " + table_notes + " ADD COLUMN " + key_remote_id + " INTEGER");
+            db.execSQL("UPDATE " + table_notes + " SET " + key_remote_id + "=" + key_id + " WHERE (" + key_remote_id + " IS NULL OR " + key_remote_id + "=0) AND " + key_status + "!=?", new String[]{DBStatus.LOCAL_CREATED.getTitle()});
+            db.execSQL("UPDATE " + table_notes + " SET " + key_remote_id + "=0, " + key_status + "=? WHERE " + key_status + "=?", new String[]{DBStatus.LOCAL_EDITED.getTitle(), DBStatus.LOCAL_CREATED.getTitle()});
+        }
+        if (oldVersion < 6) {
+            db.execSQL("ALTER TABLE " + table_notes + " ADD COLUMN " + key_favorite + " INTEGER DEFAULT 0");
+        }
+        if (oldVersion < 7) {
+            DatabaseIndexUtil.dropIndexes(db);
+            db.execSQL("ALTER TABLE " + table_notes + " ADD COLUMN " + key_category + " TEXT NOT NULL DEFAULT ''");
+            db.execSQL("ALTER TABLE " + table_notes + " ADD COLUMN " + key_etag + " TEXT");
+            DatabaseIndexUtil.createIndex(db, table_notes, key_remote_id, key_status, key_favorite, key_category, key_modified);
+        }
+        if (oldVersion < 8) {
+            final String table_temp = "NOTES_TEMP";
+            db.execSQL("CREATE TABLE " + table_temp + " ( " +
+                    key_id + " INTEGER PRIMARY KEY AUTOINCREMENT, " +
+                    key_remote_id + " INTEGER, " +
+                    key_status + " VARCHAR(50), " +
+                    key_title + " TEXT, " +
+                    key_modified + " INTEGER DEFAULT 0, " +
+                    key_content + " TEXT, " +
+                    key_favorite + " INTEGER DEFAULT 0, " +
+                    key_category + " TEXT NOT NULL DEFAULT '', " +
+                    key_etag + " TEXT)");
+            DatabaseIndexUtil.createIndex(db, table_temp, key_remote_id, key_status, key_favorite, key_category, key_modified);
+            db.execSQL(String.format("INSERT INTO %s(%s,%s,%s,%s,%s,%s,%s,%s,%s) ", table_temp, key_id, key_remote_id, key_status, key_title, key_modified, key_content, key_favorite, key_category, key_etag)
+                    + String.format("SELECT %s,%s,%s,%s,strftime('%%s',%s),%s,%s,%s,%s FROM %s", key_id, key_remote_id, key_status, key_title, key_modified, key_content, key_favorite, key_category, key_etag, table_notes));
+            db.execSQL(String.format("DROP TABLE %s", table_notes));
+            db.execSQL(String.format("ALTER TABLE %s RENAME TO %s", table_temp, table_notes));
+        }
+        if (oldVersion < 9) {
+            // Create accounts table
+            createAccountTable(db);
+
+            // Add accountId to notes table
+            db.execSQL("ALTER TABLE " + table_notes + " ADD COLUMN " + key_account_id + " INTEGER NOT NULL DEFAULT 0");
+            DatabaseIndexUtil.createIndex(db, table_notes, key_account_id);
+
+            // Migrate existing account from SharedPreferences
+            SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(context);
+            String username = sharedPreferences.getString("settingsUsername", "");
+            String url = sharedPreferences.getString("settingsUrl", "");
+            if (!url.isEmpty() && url.endsWith("/")) {
+                url = url.substring(0, url.length() - 1);
+                try {
+                    String accountName = username + "@" + new URL(url).getHost();
+
+                    ContentValues migratedAccountValues = new ContentValues();
+                    migratedAccountValues.put(key_url, url);
+                    migratedAccountValues.put(key_username, username);
+                    migratedAccountValues.put(key_account_name, accountName);
+                    db.insert(table_accounts, null, migratedAccountValues);
+
+                    // After successful insertion of migrated account, set accountId to 1 in each note
+                    ContentValues values = new ContentValues();
+                    values.put(key_account_id, 1);
+                    db.update(table_notes, values, key_account_id + " = ?", new String[]{"NULL"});
+
+                    // Add FOREIGN_KEY constraint
+                    final String table_temp = "NOTES_TEMP";
+                    db.execSQL(String.format("ALTER TABLE %s RENAME TO %s", table_notes, table_temp));
+
+                    db.execSQL("CREATE TABLE " + table_notes + " ( " +
+                            key_id + " INTEGER PRIMARY KEY AUTOINCREMENT, " +
+                            key_remote_id + " INTEGER, " +
+                            key_account_id + " INTEGER, " +
+                            key_status + " VARCHAR(50), " +
+                            key_title + " TEXT, " +
+                            key_modified + " INTEGER DEFAULT 0, " +
+                            key_content + " TEXT, " +
+                            key_favorite + " INTEGER DEFAULT 0, " +
+                            key_category + " TEXT NOT NULL DEFAULT '', " +
+                            key_etag + " TEXT," +
+                            "FOREIGN KEY(" + key_account_id + ") REFERENCES " + table_accounts + "(" + key_id + "))");
+                    DatabaseIndexUtil.createIndex(db, table_notes, key_remote_id, key_account_id, key_status, key_favorite, key_category, key_modified);
+
+                    db.execSQL(String.format("INSERT INTO %s(%s,%s,%s,%s,%s,%s,%s,%s,%s,%s) ", table_notes, key_id, key_account_id, key_remote_id, key_status, key_title, key_modified, key_content, key_favorite, key_category, key_etag)
+                            + String.format("SELECT %s,%s,%s,%s,%s,%s,%s,%s,%s,%s FROM %s", key_id, values.get(key_account_id), key_remote_id, key_status, key_title, key_modified, key_content, key_favorite, key_category, key_etag, table_temp));
+                    db.execSQL(String.format("DROP TABLE %s;", table_temp));
+
+                    AppWidgetManager awm = AppWidgetManager.getInstance(context);
+                    SharedPreferences.Editor editor = sharedPreferences.edit();
+
+                    // Add accountId '1' to any existing (and configured) appwidgets
+                    int[] appWidgetIdsNLW = awm.getAppWidgetIds(new ComponentName(context, NoteListWidget.class));
+                    int[] appWidgetIdsSNW = awm.getAppWidgetIds(new ComponentName(context, SingleNoteWidget.class));
+
+                    for (int appWidgetId : appWidgetIdsNLW) {
+                        if (sharedPreferences.getInt(NoteListWidget.WIDGET_MODE_KEY + appWidgetId, -1) >= 0) {
+                            editor.putLong(NoteListWidget.ACCOUNT_ID_KEY + appWidgetId, 1);
+                        }
+                    }
+
+                    for (int appWidgetId : appWidgetIdsSNW) {
+                        if (sharedPreferences.getLong(SingleNoteWidget.WIDGET_KEY + appWidgetId, -1) >= 0) {
+                            editor.putLong(SingleNoteWidget.ACCOUNT_ID_KEY + appWidgetId, 1);
+                        }
+                    }
+
+                    notifyNotesChanged();
+
+                    // Clean up no longer needed SharedPreferences
+                    editor.remove("notes_last_etag");
+                    editor.remove("notes_last_modified");
+                    editor.remove("settingsUrl");
+                    editor.remove("settingsUsername");
+                    editor.remove("settingsPassword");
+                    editor.apply();
+                } catch (MalformedURLException e) {
+                    Log.e(TAG, "Previous URL could not be parsed. Recreating database...");
+                    e.printStackTrace();
+                    recreateDatabase(db);
+                    return;
+                }
+            } else {
+                Log.e(TAG, "Previous URL is empty or does not end with a '/' character. Recreating database...");
+                recreateDatabase(db);
+                return;
+            }
+        }
+        if (oldVersion < 10) {
+            db.execSQL("ALTER TABLE " + table_notes + " ADD COLUMN " + key_excerpt + " INTEGER NOT NULL DEFAULT ''");
+            Cursor cursor = db.query(table_notes, new String[]{key_id, key_content}, null, null, null, null, null, null);
+            while (cursor.moveToNext()) {
+                ContentValues values = new ContentValues();
+                values.put(key_excerpt, NoteUtil.generateNoteExcerpt(cursor.getString(1)));
+                db.update(table_notes, values, key_id + " = ? ", new String[]{cursor.getString(0)});
+            }
+            cursor.close();
+        }
+    }
+
+    @Override
+    public void onDowngrade(SQLiteDatabase db, int oldVersion, int newVersion) {
+        recreateDatabase(db);
+    }
+
+    private void recreateDatabase(SQLiteDatabase db) {
+        DatabaseIndexUtil.dropIndexes(db);
+        db.execSQL("DROP TABLE IF EXISTS " + table_notes);
+        db.execSQL("DROP TABLE IF EXISTS " + table_accounts);
+        onCreate(db);
+    }
+
+    private static void createNotesIndexes(@NonNull SQLiteDatabase db) {
+        DatabaseIndexUtil.createIndex(db, table_notes, key_remote_id, key_account_id, key_status, key_favorite, key_category, key_modified);
+    }
+
+    private static void createAccountIndexes(@NonNull SQLiteDatabase db) {
+        DatabaseIndexUtil.createIndex(db, table_accounts, key_url, key_username, key_account_name, key_etag, key_modified);
+    }
+
+    protected abstract void notifyNotesChanged();
+}

app/src/main/java/it/niedermann/owncloud/notes/persistence/LoadNotesListTask.java

@@ -44,7 +44,7 @@ public class LoadNotesListTask extends AsyncTask<Void, Void, List<Item>> {
     @Override
     protected List<Item> doInBackground(Void... voids) {
         List<DBNote> noteList;
-        NoteSQLiteOpenHelper db = NoteSQLiteOpenHelper.getInstance(context);
+        NotesDatabase db = NotesDatabase.getInstance(context);
         noteList = db.searchNotes(accountId, searchQuery, category.category, category.favorite);
 
         if (category.category == null) {

app/src/main/java/it/niedermann/owncloud/notes/persistence/NoteServerSyncHelper.java

@@ -67,7 +67,7 @@ public class NoteServerSyncHelper {
 
     private static NoteServerSyncHelper instance;
 
-    private final NoteSQLiteOpenHelper db;
+    private final NotesDatabase db;
     private final Context context;
 
     // Track network connection changes using a BroadcastReceiver
@@ -110,7 +110,7 @@ public class NoteServerSyncHelper {
     private final Map<String, List<ISyncCallback>> callbacksPush = new HashMap<>();
     private final Map<String, List<ISyncCallback>> callbacksPull = new HashMap<>();
 
-    private NoteServerSyncHelper(NoteSQLiteOpenHelper db) {
+    private NoteServerSyncHelper(NotesDatabase db) {
         this.db = db;
         this.context = db.getContext();
         notesClient = new NotesClient(context.getApplicationContext());
@@ -134,7 +134,7 @@ public class NoteServerSyncHelper {
      * @param dbHelper NoteSQLiteOpenHelper
      * @return NoteServerSyncHelper
      */
-    public static synchronized NoteServerSyncHelper getInstance(NoteSQLiteOpenHelper dbHelper) {
+    public static synchronized NoteServerSyncHelper getInstance(NotesDatabase dbHelper) {
         if (instance == null) {
             instance = new NoteServerSyncHelper(dbHelper);
         }

app/src/main/java/it/niedermann/owncloud/notes/persistence/NotesDatabase.java

@@ -1,11 +1,8 @@
 package it.niedermann.owncloud.notes.persistence;
 
-import android.appwidget.AppWidgetManager;
-import android.content.ComponentName;
 import android.content.ContentValues;
 import android.content.Context;
 import android.content.Intent;
-import android.content.SharedPreferences;
 import android.content.pm.ShortcutInfo;
 import android.content.pm.ShortcutManager;
 import android.content.res.Resources;
@@ -13,10 +10,8 @@ import android.database.Cursor;
 import android.database.DatabaseUtils;
 import android.database.sqlite.SQLiteConstraintException;
 import android.database.sqlite.SQLiteDatabase;
-import android.database.sqlite.SQLiteOpenHelper;
 import android.graphics.drawable.Icon;
 import android.os.Build;
-import android.preference.PreferenceManager;
 import android.text.TextUtils;
 import android.util.Log;
 
@@ -26,8 +21,6 @@ import androidx.annotation.WorkerThread;
 
 import com.nextcloud.android.sso.model.SingleSignOnAccount;
 
-import java.net.MalformedURLException;
-import java.net.URL;
 import java.util.ArrayList;
 import java.util.Calendar;
 import java.util.Collections;
@@ -44,10 +37,9 @@ import it.niedermann.owncloud.notes.android.appwidget.SingleNoteWidget;
 import it.niedermann.owncloud.notes.model.CloudNote;
 import it.niedermann.owncloud.notes.model.DBNote;
 import it.niedermann.owncloud.notes.model.DBStatus;
+import it.niedermann.owncloud.notes.model.ISyncCallback;
 import it.niedermann.owncloud.notes.model.LocalAccount;
 import it.niedermann.owncloud.notes.model.NavigationAdapter;
-import it.niedermann.owncloud.notes.util.DatabaseIndexUtil;
-import it.niedermann.owncloud.notes.model.ISyncCallback;
 import it.niedermann.owncloud.notes.util.NoteUtil;
 
 import static it.niedermann.owncloud.notes.android.activity.EditNoteActivity.ACTION_SHORTCUT;
@@ -55,51 +47,26 @@ import static it.niedermann.owncloud.notes.android.activity.EditNoteActivity.ACT
 /**
  * Helps to add, get, update and delete Notes with the option to trigger a Resync with the Server.
  */
-public class NoteSQLiteOpenHelper extends SQLiteOpenHelper {
+public class NotesDatabase extends AbstractNotesDatabase {
 
-    private static final String TAG = NoteSQLiteOpenHelper.class.getSimpleName();
+    private static final String TAG = NotesDatabase.class.getSimpleName();
-
-    private static final int database_version = 10;
-
-    private static final String database_name = "OWNCLOUD_NOTES";
-    private static final String table_notes = "NOTES";
-    private static final String table_accounts = "ACCOUNTS";
-
-    private static final String key_id = "ID";
-
-    private static final String key_url = "URL";
-    private static final String key_account_name = "ACCOUNT_NAME";
-    private static final String key_username = "USERNAME";
-
-    private static final String key_account_id = "ACCOUNT_ID";
-    private static final String key_remote_id = "REMOTEID";
-    private static final String key_status = "STATUS";
-    private static final String key_title = "TITLE";
-    private static final String key_modified = "MODIFIED";
-    private static final String key_content = "CONTENT";
-    private static final String key_excerpt = "EXCERPT";
-    private static final String key_favorite = "FAVORITE";
-    private static final String key_category = "CATEGORY";
-    private static final String key_etag = "ETAG";
 
     private static final String[] columnsWithoutContent = {key_id, key_remote_id, key_status, key_title, key_modified, key_favorite, key_category, key_etag, key_excerpt};
     private static final String[] columns = {key_id, key_remote_id, key_status, key_title, key_modified, key_favorite, key_category, key_etag, key_excerpt, key_content};
     private static final String default_order = key_favorite + " DESC, " + key_modified + " DESC";
 
-    private static NoteSQLiteOpenHelper instance;
+    private static NotesDatabase instance;
 
     private final NoteServerSyncHelper serverSyncHelper;
-    private final Context context;
 
-    private NoteSQLiteOpenHelper(Context context) {
+    private NotesDatabase(Context context) {
-        super(context, database_name, null, database_version);
+        super(context, database_name, null);
-        this.context = context;
         serverSyncHelper = NoteServerSyncHelper.getInstance(this);
     }
 
-    public static NoteSQLiteOpenHelper getInstance(Context context) {
+    public static NotesDatabase getInstance(Context context) {
         if (instance == null)
-            return instance = new NoteSQLiteOpenHelper(context);
+            return instance = new NotesDatabase(context);
         else
             return instance;
     }
@@ -108,214 +75,6 @@ public class NoteSQLiteOpenHelper extends SQLiteOpenHelper {
         return serverSyncHelper;
     }
 
-    /**
-     * Creates initial the Database
-     *
-     * @param db Database
-     */
-    @Override
-    public void onCreate(SQLiteDatabase db) {
-        createAccountTable(db);
-        createNotesTable(db);
-    }
-
-    private void createNotesTable(@NonNull SQLiteDatabase db) {
-        db.execSQL("CREATE TABLE " + table_notes + " ( " +
-                key_id + " INTEGER PRIMARY KEY AUTOINCREMENT, " +
-                key_remote_id + " INTEGER, " +
-                key_account_id + " INTEGER, " +
-                key_status + " VARCHAR(50), " +
-                key_title + " TEXT, " +
-                key_modified + " INTEGER DEFAULT 0, " +
-                key_content + " TEXT, " +
-                key_favorite + " INTEGER DEFAULT 0, " +
-                key_category + " TEXT NOT NULL DEFAULT '', " +
-                key_etag + " TEXT," +
-                key_excerpt + " TEXT NOT NULL DEFAULT '', " +
-                "FOREIGN KEY(" + key_account_id + ") REFERENCES " + table_accounts + "(" + key_id + "))");
-        createNotesIndexes(db);
-    }
-
-    private void createAccountTable(@NonNull SQLiteDatabase db) {
-        db.execSQL("CREATE TABLE " + table_accounts + " ( " +
-                key_id + " INTEGER PRIMARY KEY AUTOINCREMENT, " +
-                key_url + " TEXT, " +
-                key_username + " TEXT, " +
-                key_account_name + " TEXT UNIQUE, " +
-                key_etag + " TEXT, " +
-                key_modified + " INTEGER)");
-        createAccountIndexes(db);
-    }
-
-    @SuppressWarnings("deprecation")
-    @Override
-    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
-        if (oldVersion < 3) {
-            recreateDatabase(db);
-            return;
-        }
-        if (oldVersion < 4) {
-            db.delete(table_notes, null, null);
-            db.delete(table_accounts, null, null);
-        }
-        if (oldVersion < 5) {
-            db.execSQL("ALTER TABLE " + table_notes + " ADD COLUMN " + key_remote_id + " INTEGER");
-            db.execSQL("UPDATE " + table_notes + " SET " + key_remote_id + "=" + key_id + " WHERE (" + key_remote_id + " IS NULL OR " + key_remote_id + "=0) AND " + key_status + "!=?", new String[]{DBStatus.LOCAL_CREATED.getTitle()});
-            db.execSQL("UPDATE " + table_notes + " SET " + key_remote_id + "=0, " + key_status + "=? WHERE " + key_status + "=?", new String[]{DBStatus.LOCAL_EDITED.getTitle(), DBStatus.LOCAL_CREATED.getTitle()});
-        }
-        if (oldVersion < 6) {
-            db.execSQL("ALTER TABLE " + table_notes + " ADD COLUMN " + key_favorite + " INTEGER DEFAULT 0");
-        }
-        if (oldVersion < 7) {
-            DatabaseIndexUtil.dropIndexes(db);
-            db.execSQL("ALTER TABLE " + table_notes + " ADD COLUMN " + key_category + " TEXT NOT NULL DEFAULT ''");
-            db.execSQL("ALTER TABLE " + table_notes + " ADD COLUMN " + key_etag + " TEXT");
-            DatabaseIndexUtil.createIndex(db, table_notes, key_remote_id, key_status, key_favorite, key_category, key_modified);
-        }
-        if (oldVersion < 8) {
-            final String table_temp = "NOTES_TEMP";
-            db.execSQL("CREATE TABLE " + table_temp + " ( " +
-                    key_id + " INTEGER PRIMARY KEY AUTOINCREMENT, " +
-                    key_remote_id + " INTEGER, " +
-                    key_status + " VARCHAR(50), " +
-                    key_title + " TEXT, " +
-                    key_modified + " INTEGER DEFAULT 0, " +
-                    key_content + " TEXT, " +
-                    key_favorite + " INTEGER DEFAULT 0, " +
-                    key_category + " TEXT NOT NULL DEFAULT '', " +
-                    key_etag + " TEXT)");
-            DatabaseIndexUtil.createIndex(db, table_temp, key_remote_id, key_status, key_favorite, key_category, key_modified);
-            db.execSQL(String.format("INSERT INTO %s(%s,%s,%s,%s,%s,%s,%s,%s,%s) ", table_temp, key_id, key_remote_id, key_status, key_title, key_modified, key_content, key_favorite, key_category, key_etag)
-                    + String.format("SELECT %s,%s,%s,%s,strftime('%%s',%s),%s,%s,%s,%s FROM %s", key_id, key_remote_id, key_status, key_title, key_modified, key_content, key_favorite, key_category, key_etag, table_notes));
-            db.execSQL(String.format("DROP TABLE %s", table_notes));
-            db.execSQL(String.format("ALTER TABLE %s RENAME TO %s", table_temp, table_notes));
-        }
-        if (oldVersion < 9) {
-            // Create accounts table
-            createAccountTable(db);
-
-            // Add accountId to notes table
-            db.execSQL("ALTER TABLE " + table_notes + " ADD COLUMN " + key_account_id + " INTEGER NOT NULL DEFAULT 0");
-            DatabaseIndexUtil.createIndex(db, table_notes, key_account_id);
-
-            // Migrate existing account from SharedPreferences
-            SharedPreferences sharedPreferences = PreferenceManager.getDefaultSharedPreferences(context);
-            String username = sharedPreferences.getString("settingsUsername", "");
-            String url = sharedPreferences.getString("settingsUrl", "");
-            if (!url.isEmpty() && url.endsWith("/")) {
-                url = url.substring(0, url.length() - 1);
-                try {
-                    String accountName = username + "@" + new URL(url).getHost();
-
-                    ContentValues migratedAccountValues = new ContentValues();
-                    migratedAccountValues.put(key_url, url);
-                    migratedAccountValues.put(key_username, username);
-                    migratedAccountValues.put(key_account_name, accountName);
-                    db.insert(table_accounts, null, migratedAccountValues);
-
-                    // After successful insertion of migrated account, set accountId to 1 in each note
-                    ContentValues values = new ContentValues();
-                    values.put(key_account_id, 1);
-                    db.update(table_notes, values, key_account_id + " = ?", new String[]{"NULL"});
-
-                    // Add FOREIGN_KEY constraint
-                    final String table_temp = "NOTES_TEMP";
-                    db.execSQL(String.format("ALTER TABLE %s RENAME TO %s", table_notes, table_temp));
-
-                    db.execSQL("CREATE TABLE " + table_notes + " ( " +
-                            key_id + " INTEGER PRIMARY KEY AUTOINCREMENT, " +
-                            key_remote_id + " INTEGER, " +
-                            key_account_id + " INTEGER, " +
-                            key_status + " VARCHAR(50), " +
-                            key_title + " TEXT, " +
-                            key_modified + " INTEGER DEFAULT 0, " +
-                            key_content + " TEXT, " +
-                            key_favorite + " INTEGER DEFAULT 0, " +
-                            key_category + " TEXT NOT NULL DEFAULT '', " +
-                            key_etag + " TEXT," +
-                            "FOREIGN KEY(" + key_account_id + ") REFERENCES " + table_accounts + "(" + key_id + "))");
-                    DatabaseIndexUtil.createIndex(db, table_notes, key_remote_id, key_account_id, key_status, key_favorite, key_category, key_modified);
-
-                    db.execSQL(String.format("INSERT INTO %s(%s,%s,%s,%s,%s,%s,%s,%s,%s,%s) ", table_notes, key_id, key_account_id, key_remote_id, key_status, key_title, key_modified, key_content, key_favorite, key_category, key_etag)
-                            + String.format("SELECT %s,%s,%s,%s,%s,%s,%s,%s,%s,%s FROM %s", key_id, values.get(key_account_id), key_remote_id, key_status, key_title, key_modified, key_content, key_favorite, key_category, key_etag, table_temp));
-                    db.execSQL(String.format("DROP TABLE %s;", table_temp));
-
-                    AppWidgetManager awm = AppWidgetManager.getInstance(context);
-                    SharedPreferences.Editor editor = sharedPreferences.edit();
-
-                    // Add accountId '1' to any existing (and configured) appwidgets
-                    int[] appWidgetIdsNLW = awm.getAppWidgetIds(new ComponentName(context, NoteListWidget.class));
-                    int[] appWidgetIdsSNW = awm.getAppWidgetIds(new ComponentName(context, SingleNoteWidget.class));
-
-                    for (int appWidgetId : appWidgetIdsNLW) {
-                        if (sharedPreferences.getInt(NoteListWidget.WIDGET_MODE_KEY + appWidgetId, -1) >= 0) {
-                            editor.putLong(NoteListWidget.ACCOUNT_ID_KEY + appWidgetId, 1);
-                        }
-                    }
-
-                    for (int appWidgetId : appWidgetIdsSNW) {
-                        if (sharedPreferences.getLong(SingleNoteWidget.WIDGET_KEY + appWidgetId, -1) >= 0) {
-                            editor.putLong(SingleNoteWidget.ACCOUNT_ID_KEY + appWidgetId, 1);
-                        }
-                    }
-
-                    notifyNotesChanged();
-
-                    // Clean up no longer needed SharedPreferences
-                    editor.remove("notes_last_etag");
-                    editor.remove("notes_last_modified");
-                    editor.remove("settingsUrl");
-                    editor.remove("settingsUsername");
-                    editor.remove("settingsPassword");
-                    editor.apply();
-                } catch (MalformedURLException e) {
-                    Log.e(TAG, "Previous URL could not be parsed. Recreating database...");
-                    e.printStackTrace();
-                    recreateDatabase(db);
-                    return;
-                }
-            } else {
-                Log.e(TAG, "Previous URL is empty or does not end with a '/' character. Recreating database...");
-                recreateDatabase(db);
-                return;
-            }
-        }
-        if (oldVersion < 10) {
-            db.execSQL("ALTER TABLE " + table_notes + " ADD COLUMN " + key_excerpt + " INTEGER NOT NULL DEFAULT ''");
-            Cursor cursor = db.query(table_notes, new String[]{key_id, key_content}, null, null, null, null, null, null);
-            while (cursor.moveToNext()) {
-                ContentValues values = new ContentValues();
-                values.put(key_excerpt, NoteUtil.generateNoteExcerpt(cursor.getString(1)));
-                db.update(table_notes, values, key_id + " = ? ", new String[]{cursor.getString(0)});
-            }
-            cursor.close();
-        }
-    }
-
-    @Override
-    public void onDowngrade(SQLiteDatabase db, int oldVersion, int newVersion) {
-        recreateDatabase(db);
-    }
-
-    private void recreateDatabase(SQLiteDatabase db) {
-        DatabaseIndexUtil.dropIndexes(db);
-        db.execSQL("DROP TABLE IF EXISTS " + table_notes);
-        db.execSQL("DROP TABLE IF EXISTS " + table_accounts);
-        onCreate(db);
-    }
-
-    private static void createNotesIndexes(@NonNull SQLiteDatabase db) {
-        DatabaseIndexUtil.createIndex(db, table_notes, key_remote_id, key_account_id, key_status, key_favorite, key_category, key_modified);
-    }
-
-    private static void createAccountIndexes(@NonNull SQLiteDatabase db) {
-        DatabaseIndexUtil.createIndex(db, table_accounts, key_url, key_username, key_account_name, key_etag, key_modified);
-    }
-
-    public Context getContext() {
-        return context;
-    }
-
     /**
      * Creates a new Note in the Database and adds a Synchronization Flag.
      *
@@ -480,15 +239,6 @@ public class NoteSQLiteOpenHelper extends SQLiteOpenHelper {
         );
     }
 
-    public void debugPrintFullDB(long accountId) {
-        validateAccountId(accountId);
-        List<DBNote> notes = getNotesCustom(accountId, "", new String[]{}, default_order, false);
-        Log.v(TAG, "Full Database (" + notes.size() + " notes):");
-        for (DBNote note : notes) {
-            Log.v(TAG, "     " + note);
-        }
-    }
-
     @NonNull
     @WorkerThread
     public Map<Long, Long> getIdMap(long accountId) {
@@ -613,7 +363,7 @@ public class NoteSQLiteOpenHelper extends SQLiteOpenHelper {
                 key_category);
         List<NavigationAdapter.NavigationItem> categories = new ArrayList<>(cursor.getCount());
         while (cursor.moveToNext()) {
-            Resources res = context.getResources();
+            Resources res = getContext().getResources();
             String category = cursor.getString(0).toLowerCase();
             int icon = NavigationAdapter.ICON_FOLDER;
             if (category.equals(res.getString(R.string.category_music).toLowerCase())) {
@@ -645,7 +395,7 @@ public class NoteSQLiteOpenHelper extends SQLiteOpenHelper {
                 key_category);
         List<NavigationAdapter.NavigationItem> categories = new ArrayList<>(cursor.getCount());
         while (cursor.moveToNext()) {
-            Resources res = context.getResources();
+            Resources res = getContext().getResources();
             String category = cursor.getString(0).toLowerCase();
             int icon = NavigationAdapter.ICON_FOLDER;
             if (category.equals(res.getString(R.string.category_music).toLowerCase())) {
@@ -796,12 +546,12 @@ public class NoteSQLiteOpenHelper extends SQLiteOpenHelper {
         getNoteServerSyncHelper().scheduleSync(ssoAccount, true);
 
         if (android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
-            ShortcutManager shortcutManager = context.getSystemService(ShortcutManager.class);
+            ShortcutManager shortcutManager = getContext().getSystemService(ShortcutManager.class);
             shortcutManager.getPinnedShortcuts().forEach((shortcut) -> {
                 String shortcutId = id + "";
                 if (shortcut.getId().equals(shortcutId)) {
                     Log.v(TAG, "Removing shortcut for " + shortcutId);
-                    shortcutManager.disableShortcuts(Collections.singletonList(shortcutId), context.getResources().getString(R.string.note_has_been_deleted));
+                    shortcutManager.disableShortcuts(Collections.singletonList(shortcutId), getContext().getResources().getString(R.string.note_has_been_deleted));
                 }
             });
         }
@@ -824,7 +574,7 @@ public class NoteSQLiteOpenHelper extends SQLiteOpenHelper {
     /**
      * Notify about changed notes.
      */
-    void notifyNotesChanged() {
+    protected void notifyNotesChanged() {
         updateSingleNoteWidgets(getContext());
         updateNoteListWidgets(getContext());
     }
@@ -832,19 +582,19 @@ public class NoteSQLiteOpenHelper extends SQLiteOpenHelper {
     void updateDynamicShortcuts(long accountId) {
         new Thread(() -> {
             if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.N_MR1) {
-                ShortcutManager shortcutManager = context.getApplicationContext().getSystemService(ShortcutManager.class);
+                ShortcutManager shortcutManager = getContext().getApplicationContext().getSystemService(ShortcutManager.class);
                 if (!shortcutManager.isRateLimitingActive()) {
                     List<ShortcutInfo> newShortcuts = new ArrayList<>();
 
                     for (DBNote note : getRecentNotes(accountId)) {
                         if (!TextUtils.isEmpty(note.getTitle())) {
-                            Intent intent = new Intent(context.getApplicationContext(), EditNoteActivity.class);
+                            Intent intent = new Intent(getContext().getApplicationContext(), EditNoteActivity.class);
                             intent.putExtra(EditNoteActivity.PARAM_NOTE_ID, note.getId());
                             intent.setAction(ACTION_SHORTCUT);
 
-                            newShortcuts.add(new ShortcutInfo.Builder(context.getApplicationContext(), note.getId() + "")
+                            newShortcuts.add(new ShortcutInfo.Builder(getContext().getApplicationContext(), note.getId() + "")
                                     .setShortLabel(note.getTitle() + "")
-                                    .setIcon(Icon.createWithResource(context.getApplicationContext(), note.isFavorite() ? R.drawable.ic_star_yellow_24dp : R.drawable.ic_star_grey_ccc_24dp))
+                                    .setIcon(Icon.createWithResource(getContext().getApplicationContext(), note.isFavorite() ? R.drawable.ic_star_yellow_24dp : R.drawable.ic_star_grey_ccc_24dp))
                                     .setIntent(intent)
                                     .build());
                         } else {

app/src/main/java/it/niedermann/owncloud/notes/persistence/SyncWorker.java

@@ -37,7 +37,7 @@ public class SyncWorker extends Worker {
     @NonNull
     @Override
     public Result doWork() {
-        NoteSQLiteOpenHelper db = NoteSQLiteOpenHelper.getInstance(getApplicationContext());
+        NotesDatabase db = NotesDatabase.getInstance(getApplicationContext());
         for (LocalAccount account : db.getAccounts()) {
             try {
                 SingleSignOnAccount ssoAccount = AccountImporter.getSingleSignOnAccount(getApplicationContext(), account.getAccountName());

fastlane/metadata/android/en-US/changelogs/83.txt

@@ -0,0 +1,5 @@
+- Split up NoteSQLiteOpenHelper (#750)
+
+
+Requires at least Files app¹ version 3.9.0
+¹ https://github.com/nextcloud/android