How to cut generate time to generate QR Code using Zxing

Question

I'm creating an app with QR barcode. The barcode load correctly, but somehow it load bit slow, about 3-5 secs after i tap/click the menu.

Can we make it faster? or is it normal the page load that long? other part loading only takes 1 sec or less. the app also offline, so no internet connection needed.

here my code to generate the QR barcode:

ImageView imageViewBarcode = (ImageView)findViewById(R.id.imageViewBarcode);

    try {
        bitmap = TextToImageEncode(barcode_user);

        imageViewBarcode.setImageBitmap(bitmap);

    } catch (WriterException e) {
        e.printStackTrace();
    }

Those code above is put inside onCreate. So when the page load, it generate the barcode.

Here the function to create barcode

Bitmap TextToImageEncode(String Value) throws WriterException {
    BitMatrix bitMatrix;
    try {
        bitMatrix = new MultiFormatWriter().encode(
                Value,
                BarcodeFormat.DATA_MATRIX.QR_CODE,
                QRcodeWidth, QRcodeWidth, null
        );

    } catch (IllegalArgumentException Illegalargumentexception) {

        return null;
    }
    int bitMatrixWidth = bitMatrix.getWidth();

    int bitMatrixHeight = bitMatrix.getHeight();

    int[] pixels = new int[bitMatrixWidth * bitMatrixHeight];

    for (int y = 0; y < bitMatrixHeight; y++) {
        int offset = y * bitMatrixWidth;

        for (int x = 0; x < bitMatrixWidth; x++) {

            pixels[offset + x] = bitMatrix.get(x, y) ?
                    getResources().getColor(R.color.colorBlack):getResources().getColor(R.color.colorWhite);
        }
    }
    Bitmap bitmap = Bitmap.createBitmap(bitMatrixWidth, bitMatrixHeight, Bitmap.Config.ARGB_4444);

    bitmap.setPixels(pixels, 0, 500, 0, 0, bitMatrixWidth, bitMatrixHeight);
    return bitmap;
}

Answer 1

You are calling getResources().getColor() inside double loop - ie when your image size is 100*100 pixels this will be called 10000 times. Instead assign color values to some variables outside of the loops and use these variables inside loops.

int color_black = getResources().getColor(R.color.colorBlack);
int color_white = getResources().getColor(R.color.colorWhite);

for (int y = 0; y < bitMatrixHeight; y++) {
    int offset = y * bitMatrixWidth;

    for (int x = 0; x < bitMatrixWidth; x++) {
        pixels[offset + x] = bitMatrix.get(x, y) ? color_black : color_white;
    }
}

EDIT: added code example