Cannot parse file exported from WPS Office (Android)

[kedarkarkee]

I get a weird bug on trying to parse an excel file exported from WPS Office (Android).

At first, the error was

Null check operator used on null value coming from Line 610 on parser.dart.

It was the null assertion operator on sharedString variable

      case 's':
        final sharedString = _excel._sharedStrings
            .value(int.parse(_parseValue(node.findElements('v').first)));
        value = TextCellValue.span(sharedString!.textSpan);
        break;

I changed it to

      case 's':
        final sharedString = _excel._sharedStrings
            .value(int.parse(_parseValue(node.findElements('v').first)));
        value = TextCellValue.span(sharedString?.textSpan ?? TextSpan(text: 'CHECK'));
        break;

and the parser went through but the rows are mismatched.

My excel file is like this

The parser output is (converted to strings)

[Item Name, Category, Sales Price, Purchase Price, Opening Stock, Low Stock, Item Code, HS code, Description]
[Coca Cola 2L, Drinks, 120, 80, 25, 5, null, 12893773.0, Best drinks]
[Fanta 1L, Drinks, 100, 70, 30, null, null, null, null]
[Mountain Dew 1L, null, 110, 75, 15, 10, MD1, 939783, null]
[Real Juice 250ml, General, 50, 35, 60, null, null, null, Fruit Juice]
[null, bbb, null, null, null, null, null, 8.9, null]
[null, hhh, null, null, null, null, null, hsgs8282, null]
[null, hhhh, null, null, null, null, null, CHECK, null]
[null, 8.9.8, null, null, null, null, null, null, null]

Notice the last three rows on the file and on the parsed data, Also notice the CHECK keyword I added to fix null assertion keyword.

The file is

wpsExportedExample.xlsx

[rafiz001]

Another affected file: Class Routine (Summer-25).xlsx

This file is exported from Google Sheet.

[mhanuska-coder]

I experienced a very similar issue with excel 4.0.6.

The XLSX file opened normally in Microsoft Excel 2021, but Flutter excel failed while parsing it with a null check exception.

What fixed it 100% for me was:

Open the XLSX file in Excel.
Save it as XLS (Excel 97-2003 Workbook).
Open the XLS file.
Save it again as XLSX.

After this conversion, the same data loaded correctly in the Flutter excel package.

This suggests that some XLSX files contain internal structures that Microsoft Excel can read, but the parser cannot handle correctly. The XLS -> XLSX conversion appears to rewrite the workbook into a simpler format that the parser accepts.