用zxing解码QRCode。 Java的

Question

I generated a QRCode using zxing library.

    QRCode qrcode = QRCode.from("Encoding string").withSize(17,17).to(ImageType.PNG);
    ByteArrayOutputStream out = QRCode.from(output.toString()).withSize(10, 10).to(ImageType.PNG).stream();
    FileOutputStream fout = new FileOutputStream(new File("D:\\QR_Code.JPG"));
    fout.write(out.toByteArray());
    fout.flush();
    fout.close();

It works fine but now I want to decode generated QRCode. Is it possible to decode QRCode from an image with zxing? If so, can you give me a hint how to do it because I haven't found appropriate class or method. Thanks in advance.

Answer 1

Here is what you can do:

• You'll need an instance of QRCodeReader to decode qrcode data from a BinaryBitmap
• You need to instanciate a HybridBinarizer and pass it as a constructor argument to create your BinaryBitmap
• The HybridBinarizer needs an instance of LuminanceSource
• Take a look at BufferedImageLuminanceSource

Here is an example that would decode data from a buffered image:

public static String qrDecodeFromImage(BufferedImage img) {
        if(img!=null) {
            LuminanceSource bfImgLuminanceSource = new BufferedImageLuminanceSource(img);
            BinaryBitmap binaryBmp = new BinaryBitmap(new HybridBinarizer(bfImgLuminanceSource));
            QRCodeReader qrReader = new QRCodeReader();
            Result result;
            try {
                result = qrReader.decode(binaryBmp);
                return result.getText();
            } catch (NotFoundException e) {} catch (ChecksumException e) {} catch (FormatException e) {}
        }
        return null;
    }

Answer 2

You'll need to have the ZXing project included in your project(source, etc).

Then you can use all sorts of ZXing classes to performing decoding/encoding, etc:

Look into these classes: BinaryBitmap , QRCodeReader , ParsedResult , ResultParser and give this a try:

Bitmap b = ...;//TODO: create a bitmap from your source...
BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(new RGBLuminanceSource(b)));
Result result = null;
QRCodeReader reader = new QRCodeReader();
try {
    result = reader.decode(bitmap);
    ParsedResult parsedResult = ResultParser.parseResult(result);
    //TODO: use parsedResult
}
catch(OutOfMemoryError e) {

}
catch(Exception e) {

}