Extraer tarjeta en flutter

main.dart

final String creditPattern = r"(\d{4}) (\d{4}) (\d{4}) (\d{4})";
final RegExp cardRegexp = RegExp(creditPattern);
final expPattern = r"(\d{2})\/(\d{2})";
final expRegexp = RegExp(expPattern);

final VisionText visionText =
    await textRecognizer.processImage(visionImage);
for (TextBlock block in visionText.blocks) {
  for (TextLine line in block.lines) {
    if (cardRegexp.hasMatch(line.text)) {
      setState(() {
        tarjetaCredito = line.text;
      });
    }
    if (expRegexp.hasMatch(line.text)) {
      final allMatches = expRegexp.firstMatch(line.text);
      final month = int.parse(allMatches.group(1));
      final year = int.parse(allMatches.group(2));
      setState(() {
        expMonth = month;
        expYear = year;
      });
    }
  }
}