Не получается добавить данные в базу данных

Я использую бд SQLite для сохранения данных, но когда я запускаю свое приложение, переменная cursor остается пустой, и когда я достаю данные из него появляется ошибка:

E/AndroidRuntime: FATAL EXCEPTION: main
    Process: com.example.myapplication, PID: 9095
    android.database.CursorIndexOutOfBoundsException: Index -1 requested, with a size of 0
        at android.database.AbstractCursor.checkPosition(AbstractCursor.java:521)
        at android.database.AbstractWindowedCursor.checkPosition(AbstractWindowedCursor.java:139)
        at android.database.AbstractWindowedCursor.getInt(AbstractWindowedCursor.java:71)
        at com.example.myapplication.DatabaseCalendar.getDates(DatabaseCalendar.java:81)
        at com.example.myapplication.CalendarAdapter.getView(CalendarAdapter.java:44)
        at android.widget.AbsListView.obtainView(AbsListView.java:2398)
        at android.widget.GridView.onMeasure(GridView.java:1086)
        at android.view.View.measure(View.java:25773)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6980)
        at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1552)
        at android.widget.LinearLayout.measureVertical(LinearLayout.java:842)
        at android.widget.LinearLayout.onMeasure(LinearLayout.java:721)
        at android.view.View.measure(View.java:25773)
        at androidx.constraintlayout.widget.ConstraintLayout$Measurer.measure(ConstraintLayout.java:792)
        at androidx.constraintlayout.solver.widgets.analyzer.BasicMeasure.measure(BasicMeasure.java:480)
        at androidx.constraintlayout.solver.widgets.analyzer.BasicMeasure.measureChildren(BasicMeasure.java:134)
        at androidx.constraintlayout.solver.widgets.analyzer.BasicMeasure.solverMeasure(BasicMeasure.java:277)
        at androidx.constraintlayout.solver.widgets.ConstraintWidgetContainer.measure(ConstraintWidgetContainer.java:119)
        at androidx.constraintlayout.widget.ConstraintLayout.resolveSystem(ConstraintLayout.java:1578)
        at androidx.constraintlayout.widget.ConstraintLayout.onMeasure(ConstraintLayout.java:1690)
        at android.view.View.measure(View.java:25773)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6980)
        at android.widget.FrameLayout.onMeasure(FrameLayout.java:194)
        at android.view.View.measure(View.java:25773)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6980)
        at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1552)
        at android.widget.LinearLayout.measureVertical(LinearLayout.java:842)
        at android.widget.LinearLayout.onMeasure(LinearLayout.java:721)
        at android.view.View.measure(View.java:25773)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6980)
        at android.widget.FrameLayout.onMeasure(FrameLayout.java:194)
        at com.android.internal.policy.DecorView.onMeasure(DecorView.java:761)
        at android.view.View.measure(View.java:25773)
        at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:3608)
        at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:2407)
        at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2677)
        at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:2126)
        at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:8649)
        at android.view.Choreographer$CallbackRecord.run(Choreographer.java:1037)
        at android.view.Choreographer.doCallbacks(Choreographer.java:845)
        at android.view.Choreographer.doFrame(Choreographer.java:780)
        at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:1022)
        at android.os.Handler.handleCallback(Handler.java:938)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loopOnce(Looper.java:201)
        at android.os.Looper.loop(Looper.java:288)
        at android.app.ActivityThread.main(ActivityThread.java:7842)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:548)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1003)
W/System: A resource failed to call close. 
 

Класс базы данных:

    public DatabaseCalendar(Context context) {
        super(context, DBName, null, DATABASE_VERSION);
        //3rd argument to be passed is CursorFactory instance
    }

    @Override
    public void onCreate(SQLiteDatabase db) {
        String CREATE_HABITS_TABLE = " CREATE TABLE " + datesTable + " ( "
                + id + " INTEGER PRIMARY KEY, " + habitId + " INTEGER, "
                + month + " TEXT, "+dates +" INTEGER "+" ) ";
        db.execSQL(CREATE_HABITS_TABLE);
    }

    @Override
    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
        db.execSQL("DROP TABLE IF EXISTS " + datesTable);
        onCreate(db);
    }

    void addDate(int habId, int d) {
        SQLiteDatabase db = this.getWritableDatabase();
        ContentValues values = new ContentValues();
        values.put(habitId, habId);
        values.put(dates, d);
        db.insert(datesTable, null, values);
        db.close();
    }

    public ArrayList<Integer> getDates() {
        ArrayList<Integer> list = new ArrayList<>();
        String selectQuery = " SELECT dates FROM  datesTable";

        SQLiteDatabase db = this.getWritableDatabase();
        Cursor cursor = db.rawQuery(selectQuery,null);
        if (cursor.getCount()!=0) {
            do {
              list.add(cursor.getInt(0));
                list.add(7);
            } while (cursor.moveToNext());
        }
        cursor.close();
        return list;
    }

public int updateHabit(int habId, int d, int id) {
        SQLiteDatabase db = this.getWritableDatabase();
        ContentValues values = new ContentValues();
        values.put(dates, d);
        return db.update(datesTable, values, id + " = ?",
                new String[]{String.valueOf(id)});
    }

}