android - 将数据库保存为 CSV 文件时，为什么最后 3 列会变成一两列？

Question

为什么在将数据库保存为 CSV 文件时最后 3 列会变成一两列？

几乎所有的列都保存正确，除了最后 3 个

Here is the problem

代码如下:

//export DB to CSV file
    public static String currentFilePathOfsavingCSVtoSD;
    public static void exportDBtoCSVsaveonSD() {

        String currentDateString = new SimpleDateFormat("yyyy-MM-dd HH-mm-ss").format(Calendar.getInstance().getTime());
        File dbFile = new File("/data/data/" + "com.exactly.scooltr.inventoryAppBasic" + "/databases/" + DATABASE_NAME);
        File exportDir = new File(Environment.getExternalStorageDirectory(), "/" + main_folder+ "/CSV_files/");
        if (!exportDir.exists()) {
            exportDir.mkdirs();
        }

        File file = new File(exportDir, "("+currentDateString+")"+"simpleinventorycsv.csv");
        currentFilePathOfsavingCSVtoSD = file.toString();
        try {
            file.createNewFile();
            CSVWriter csvWrite = new CSVWriter(new FileWriter(file));
            SQLiteDatabase db = mDbHelper.getReadableDatabase();
            Cursor curCSV = db.rawQuery("SELECT " + ProductContract.ProductEntry.COLUMN_PRODUCT_NAME+", "+ProductContract.ProductEntry.COLUMN_PRODUCT_PRICE+", "+
                            ProductContract.ProductEntry.COLUMN_PRODUCT_QUANTITY+", "+ProductContract.ProductEntry.COLUMN_PRODUCT_SOLD+", "+
                            ProductContract.ProductEntry.COLUMN_PRODUCT_BARCODE+", "+ProductContract.ProductEntry.COLUMN_PRODUCT_LOCATION+", "+
                            ProductContract.ProductEntry.COLUMN_PRODUCT_CATEGORY+", "+ProductContract.ProductEntry.COLUMN_PRODUCT_NOTE +
                             " FROM " + ProductContract.ProductEntry.TABLE_NAME , null);
            csvWrite.writeNext(curCSV.getColumnNames());
            while (curCSV.moveToNext()) {
                //Columns I want to export
                String arrStr[] = {curCSV.getString(0),curCSV.getString(1), curCSV.getString(2),curCSV.getString(3),curCSV.getString(4),curCSV.getString(5)+curCSV.getString(6)+curCSV.getString(7)};
                csvWrite.writeNext(arrStr);
            }
            successSavingAsCSV=true;
            csvWrite.close();
            curCSV.close();
        } catch (Exception sqlEx) {
            Log.e("ProductProvider", sqlEx.getMessage(), sqlEx);
        }
    }


}

Answer 1

您的代码通过了最后三列，因为您使用 + 而不是使用 , 将它们视为单独的参数

即:-

String arrStr[] = {
    curCSV.getString(0),
    curCSV.getString(1), 
    curCSV.getString(2),
    curCSV.getString(3),
    curCSV.getString(4),
    curCSV.getString(5)+curCSV.getString(6)+curCSV.getString(7)
};

应该是:-

String arrStr[] = {
    curCSV.getString(0),
    curCSV.getString(1), 
    curCSV.getString(2),
    curCSV.getString(3),
    curCSV.getString(4),
    curCSV.getString(5), //<<<< comma instead of +
    curCSV.getString(6), //<<<< comma instead of +
    curCSV.getString(7)
};

然而，以下内容会更有弹性，因为它使用计算的偏移量而不是硬编码的列索引偏移量:-

String arrStr[] = {
    curCSV.getString(curCSV.getColumnIndex(ProductContract.ProductEntry.COLUMN_PRODUCT_NAME)),
    curCSV.getString(curCSV.getColumnIndex(ProductContract.ProductEntry.COLUMN_PRODUCT_PRICE)), 
    curCSV.getString(curCSV.getColumnIndex(ProductContract.ProductEntry.COLUMN_PRODUCT_QUANTITY)),
    curCSV.getString(curCSV.getColumnIndex(ProductContract.ProductEntry.COLUMN_PRODUCT_SOLD)),
    curCSV.getString(curCSV.getColumnIndex(ProductContract.ProductEntry.COLUMN_PRODUCT_BARCODE)),
    curCSV.getString(curCSV.getColumnIndex(ProductContract.ProductEntry.COLUMN_PRODUCT_LOCATION)), //<<<< comma instead of +
    curCSV.getString(curCSV.getColumnIndex(ProductContract.ProductEntry.COLUMN_PRODUCT_CATEGORY)), //<<<< comma instead of +
    curCSV.getString(curCSV.getColumnIndex(ProductContract.ProductEntry.COLUMN_PRODUCT_NOTE))
};