最近在開發專案中，需要在APP中生成二維碼，我使用的Google Zxing的庫：
點選下載Zxing-core.jar

1、生成二維碼圖片

   /**
     * 生成二維碼圖片
     *
     * @param str 二維碼內容
     * @return
     */
    public static Bitmap createBarcode(String str) {
        Bitmap bitmap = null;
        BitMatrix result = null;
        MultiFormatWriter multiFormatWriter = new
 
 MultiFormatWriter();
        try {
            result = multiFormatWriter.encode(str, BarcodeFormat.QR_CODE, 260, 260);

            int w = result.getWidth();
            int h = result.getHeight();
            int[] pixels = new int[w * h];
            for (int y = 0; y < h; y++) {
                int
 
 offset = y * w;
                for (int x = 0; x < w; x++) {
                    pixels[offset + x] = result.get(x, y) ? Color.BLACK : Color.WHITE;
                }
            }
            bitmap = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888);
            bitmap.setPixels(pixels, 0, w, 0, 0
 
, w, h);

        } catch (WriterException e) {
            e.printStackTrace();
        } catch (IllegalArgumentException e) {
            e.printStackTrace();
        }
        return bitmap;
    }

2、為二維碼增加Logo圖

  /**
     * 為二維碼增加logo圖片
     *
     * @param qrBitmap
     * @param logoBitmap
     * @return
     */
public static Bitmap addLogo(Bitmap qrBitmap, Bitmap logoBitmap) {
        int qrBitmapWidth = qrBitmap.getWidth();
        int qrBitmapHeight = qrBitmap.getHeight();
        int logoBitmapWidth = logoBitmap.getWidth();
        int logoBitmapHeight = logoBitmap.getHeight();
        Bitmap blankBitmap = Bitmap.createBitmap(qrBitmapWidth, qrBitmapHeight, Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(blankBitmap);
        canvas.drawBitmap(qrBitmap, 0, 0, null);
        canvas.save(Canvas.ALL_SAVE_FLAG);
        float scaleSize = 1.0f;
        while ((logoBitmapWidth / scaleSize) > (qrBitmapWidth / 5) || (logoBitmapHeight / scaleSize) > (qrBitmapHeight / 5)) {
            scaleSize *= 2;
        }
        float sx = 1.0f / scaleSize;
        canvas.scale(sx, sx, qrBitmapWidth / 2, qrBitmapHeight / 2);
        canvas.drawBitmap(logoBitmap, (qrBitmapWidth - logoBitmapWidth) / 2, (qrBitmapHeight - logoBitmapHeight) / 2, null);
        canvas.restore();
        return blankBitmap;
    }

3、直接呼叫

Bitmap qrBitmap = createBarcode(mUrl);
Bitmap logoBitmap = BitmapFactory.decodeResource(getResources(), R.mipmap.ic_launcher);