问从数据库中检索数据，并使用android中的MPAndroidChart在条形图中显示这些数据

EN

public ArrayList<String> queryXData(){
    ArrayList<String> xNewData = new ArrayList<String>();
    String query = "SELECT " + DAILY_DATE + " FROM " + TABLE_DAILY_FRAG;
    Cursor cursor = mSQLiteDatabase.rawQuery(query, null);
    for (cursor.moveToFirst(); !cursor.isAfterLast(); cursor.moveToNext()) {
        xNewData.add(cursor.getString(cursor.getColumnIndex(DAILY_DATE)));
    }
    cursor.close();
    return xNewData;
}

public ArrayList<Float> queryYData(){
    ArrayList<Float> yNewData = new ArrayList<Float>();
    String query = "SELECT " + DAILY_TOTAL + " FROM " + TABLE_DAILY_FRAG;
    Cursor cursor = mSQLiteDatabase.rawQuery(query, null);
    for (cursor.moveToFirst(); !cursor.isAfterLast(); cursor.moveToNext()) {
        yNewData.add(cursor.getFloat(cursor.getColumnIndex(DAILY_TOTAL)));
    }
    cursor.close();
    return yNewData;
}

private void addData(){

    ArrayList<BarEntry> yVals = new ArrayList<BarEntry>();

    for (int i = 0; i < mExpenseDB.queryYData().size(); i++)
        yVals.add(new BarEntry(mExpenseDB.queryYData().get(i), i));

    ArrayList<String> xVals = new ArrayList<String>();
    for(int i = 0; i < mExpenseDB.queryXData().size(); i++)
        xVals.add(mExpenseDB.queryXData().get(i));

    BarDataSet dataSet = new BarDataSet(yVals, "expense values");
    dataSet.setColors(ColorTemplate.COLORFUL_COLORS);

    BarData data = new BarData(xVals, dataSet);


    LimitLine line = new LimitLine(12f, "average daily expense");
    line.setTextSize(12f);
    line.setLineWidth(4f);
    YAxis leftAxis = barChart.getAxisLeft();
    leftAxis.addLimitLine(line);

    barChart.setData(data);
    barChart.setDescription("The expenses chart.");
    barChart.animateY(2000);

}