参考

zxing扫描二维码和识别图片二维码及其优化策略

一、zxing 集成

我集成 zxing 的主要方法是复制关键代码到自己的项目中。集成的代码中删除了share，history，help等无用的代码。集成后的效果图如下所示：

scan.jpg

注：该UI是自定义的UI界面，并不是官方自带的

zxing 的官方项目地址是： https://github.com/zxing/zxing。当前最新版是3.3.0。目录结构如下：

zxing目录结构.png

跟android有关的 是 core，android-core,android-integration ,以及android。其中 android 包是一个完整的demo。里面包含了一些分享，历史管理，设置，帮助之类的主菜单。
进入release页面：https://github.com/zxing/zxing/releases，下载最新的代码。

在使用时可以把 目录 core 导出为 jar 包，然后放入项目的lib目录中，也可以直接添加依赖（添加依赖时去官网看看当前的最新版本）：

implementation 'com.google.zxing:android-core:3.3.0'
implementation 'com.google.zxing:core:3.3.3'

把 zxing 包中的关键类拷贝到项目中

拷贝后如下图所示

集成目录.png

拷贝相关资源文件

1. 将 drawable 中的内容拷贝过来

drawable.png

2. 将raw文件夹都拷过去

raw.png

3. values下的文件拷贝要小心一点！比如：对于colors.xml文件，我们需要把其中Zxing相关的代码考到自己的colors.xml中去， 而不是简单的替换，其他文件也类似！

value.png

4. 将 xml 文件拷贝过去

xml.png

5 拷贝manifest.xml文件中的相关权限及CaptureActivity 类加入代码

 <uses-permission android:name="android.permission.CAMERA"/>
 <uses-permission android:name="android.permission.INTERNET"/>
 <uses-permission android:name="android.permission.VIBRATE"/>
 <uses-permission android:name="android.permission.FLASHLIGHT"/>

// CaptureActivity 类加入的部分代码，扫描页面全屏没有状态栏
@Override
public void onCreate(Bundle icicle) {
    requestWindowFeature(Window.FEATURE_NO_TITLE);
    getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN, WindowManager.LayoutParams.FLAG_FULLSCREEN);
    super.onCreate(icicle);
    //window设置标志位，保证屏幕常亮不会黑屏
    Window window = getWindow();
    window.addFlags(WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON);
    setContentView(R.layout.activity_qrcode_capture_layout);
    inactivityTimer = new InactivityTimer(this);
    beepManager = new BeepManager(this);
    ambientLightManager = new AmbientLightManager(this);
    cameraManager = new CameraManager(getApplication());
}

window 设置标志位，保证屏幕常亮不会黑屏，
InactivityTimer 保证在电量较低的时候且一段时间没有激活的时候，关闭CaptureActivity，
BeepManager 是用来扫码时发出声音和震动的，
AmbientLightManager 是用来控制感光的，以此来控制闪光灯的开闭
CaptureActivity,扫描界面，也是官方demo的主界面。
CaptureActivityHandler,辅助扫描界面，进行一些逻辑的处理，消息的转发。
CameraManager,Camera,相机有关的部分，如 预览，自动聚焦
DecodeThread，DecodeHandler, 跟解码有关的类，线程，消息处理
BarcodeFormat, DecodeHintType, 支持的一些类型，格式，配置。如，二维码，各种条形码，字符集。

自定义扫码框 ViewfinderView

以下是关键代码

    @Override
    public void onDraw(Canvas canvas) {
        if (cameraManager == null) {
            return; // not ready yet, early draw before done configuring
        }
        Rect frame = cameraManager.getFramingRect();
        Rect previewFrame = cameraManager.getFramingRectInPreview();
        if (frame == null || previewFrame == null) {
            return;
        }
        int width = canvas.getWidth();
        int height = canvas.getHeight();

        // Draw the exterior (i.e. outside the framing rect) darkened
        paint.setColor(resultBitmap != null ? resultColor : maskColor);
        canvas.drawRect(0, 0, width, frame.top, paint);
        canvas.drawRect(0, frame.top, frame.left, frame.bottom + 1, paint);
        canvas.drawRect(frame.right + 1, frame.top, width, frame.bottom + 1, paint);
        canvas.drawRect(0, frame.bottom + 1, width, height, paint);

        if (resultBitmap != null) {
            // Draw the opaque result bitmap over the scanning rectangle
            paint.setAlpha(CURRENT_POINT_OPACITY);
            canvas.drawBitmap(resultBitmap, null, frame, paint);
        } else {

            // Draw a red "laser scanner" line through the middle to show decoding is active
            paint.setColor(Color.BLUE);
            paint.setAlpha(SCANNER_ALPHA[scannerAlpha]);
            scannerAlpha = (scannerAlpha + 1) % SCANNER_ALPHA.length;
            //绘制左上角的两个小矩形
            canvas.drawRect(frame.left, frame.top, frame.left + ScreenRate, frame.top + CORNER_WIDTH, paint);
            canvas.drawRect(frame.left, frame.top, frame.left + CORNER_WIDTH, frame.top + ScreenRate, paint);
            //绘制右上角的两个小矩形
            canvas.drawRect(frame.right - ScreenRate, frame.top, frame.right, frame.top + CORNER_WIDTH, paint);
            canvas.drawRect(frame.right - CORNER_WIDTH, frame.top, frame.right, frame.top + ScreenRate, paint);
            //绘制左下角的两个小矩形
            canvas.drawRect(frame.left, frame.bottom - CORNER_WIDTH, frame.left + ScreenRate, frame.bottom, paint);
            canvas.drawRect(frame.left, frame.bottom - ScreenRate, frame.left + CORNER_WIDTH, frame.bottom, paint);
            //绘制右下角的两个小矩形
            canvas.drawRect(frame.right - ScreenRate, frame.bottom - CORNER_WIDTH, frame.right, frame.bottom, paint);
            canvas.drawRect(frame.right - CORNER_WIDTH, frame.bottom - ScreenRate, frame.right, frame.bottom, paint);

            //记录矩形框的上和下
            if (!isFirst) {
                isFirst = true;
                slideTop = frame.top;
                slideBottom = frame.bottom;
            }
            //定义好扫描线每秒移动速度
            slideTop += SPEED_DISTANCE;
            if (slideTop >= slideBottom) {
                slideTop = frame.top;
            }
            //绘制扫描线
            Rect lineRect = new Rect();
            lineRect.left = frame.left;
            lineRect.right = frame.right;
            lineRect.top = slideTop;
            lineRect.bottom = slideTop + 18;
            //绘制一个bitmap
            canvas.drawBitmap(((BitmapDrawable) (getResources().getDrawable(R.drawable.fle))).getBitmap(),
                    null, lineRect, paint);
            //绘制文本
            paint.setColor(Color.WHITE);
            paint.setTextSize(TEXT_SIZE * density);
            paint.setAlpha(0x40);
            paint.setTypeface(Typeface.create("System", Typeface.BOLD));
            String text = getResources().getString(R.string.scan_text);
            float textWidth = paint.measureText(text);
            canvas.drawText(text, (width - textWidth) / 2, frame.bottom + (float) TEXT_PADDING_TOP * density, paint);

            float scaleX = frame.width() / (float) previewFrame.width();
            float scaleY = frame.height() / (float) previewFrame.height();

            List<ResultPoint> currentPossible = possibleResultPoints;
            List<ResultPoint> currentLast = lastPossibleResultPoints;
            int frameLeft = frame.left;
            int frameTop = frame.top;
            if (currentPossible.isEmpty()) {
                lastPossibleResultPoints = null;
            } else {
                possibleResultPoints = new ArrayList<>(5);
                lastPossibleResultPoints = currentPossible;
                paint.setAlpha(CURRENT_POINT_OPACITY);
                paint.setColor(resultPointColor);
                synchronized (currentPossible) {
                    for (ResultPoint point : currentPossible) {
                        canvas.drawCircle(frameLeft + (int) (point.getX() * scaleX),
                                frameTop + (int) (point.getY() * scaleY),
                                POINT_SIZE, paint);
                    }
                }
            }
            if (currentLast != null) {
                paint.setAlpha(CURRENT_POINT_OPACITY / 2);
                paint.setColor(resultPointColor);
                synchronized (currentLast) {
                    float radius = POINT_SIZE / 2.0f;
                    for (ResultPoint point : currentLast) {
                        canvas.drawCircle(frameLeft + (int) (point.getX() * scaleX),
                                frameTop + (int) (point.getY() * scaleY),
                                radius, paint);
                    }
                }
            }

            // Request another update at the animation interval, but only repaint the laser line,
            // not the entire viewfinder mask.
            postInvalidateDelayed(ANIMATION_DELAY,
                    frame.left - POINT_SIZE,
                    frame.top - POINT_SIZE,
                    frame.right + POINT_SIZE,
                    frame.bottom + POINT_SIZE);
        }
    }

二、zxing 识别图片二维码

主要代码是在 CaptureActivity 中完成.
首先要打开手机相册，找到二维码图片，代码如下所示：

// 打开手机中的相册
// "android.intent.action.GET_CONTENT"
Intent innerIntent = new Intent(Intent.ACTION_GET_CONTENT);
innerIntent.setType("image/*");
Intent wrapperIntent = Intent.createChooser(innerIntent, "选择二维码图片");
startActivityForResult(wrapperIntent, REQUEST_CODE);

然后在以下方法中接收处理返回结果

private Uri uri;
@Override
    public void onActivityResult(int requestCode, int resultCode, Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if (resultCode == RESULT_OK) {
            // 首先获取到此图片的Uri
            uri = data.getData();
            //获取选取的图片的绝对地址
            String photoPath = getRealFilePath(this, data.getData());
            if (photoPath == null) {
                Toast.makeText(getApplicationContext(), "路径获取失败", Toast.LENGTH_SHORT).show();
            } else {
                //解析图片
                parsePhoto(photoPath);
            }
        }
    }

    /**
     * 获取选取的图片的绝对地址
     * @param c
     * @param uri
     * @return
     */
    private String getRealFilePath(Context c, Uri uri) {
        String result;
        Cursor cursor = c.getContentResolver().query(uri,
                new String[]{MediaStore.Images.ImageColumns.DATA},
                null, null, null);
        if (cursor == null) {
            result = uri.getPath();
        } else {
            cursor.moveToFirst();
            int index = cursor.getColumnIndex(MediaStore.Images.ImageColumns.DATA);
            result = cursor.getString(index);
            cursor.close();
        }
        return result;
    }
  

其中的核心内容是zxing扫描路径图片的功能，是parsePhoto方法 由于这个方法是耗时的 所以需要用AsyncTask 或者Rxjava 这里用的是AsyncTask。具体代码如下：

    /**
     * 启动线程解析二维码图片
     *
     * @param path
     */
    private void parsePhoto(String path) {
        //启动线程完成图片扫码
        new QrCodeAsyncTask(this, path).execute(path);
    }

    /**
     * AsyncTask 静态内部类，防止内存泄漏
     */
    static class QrCodeAsyncTask extends AsyncTask<String, Integer, String> {
        private WeakReference<Activity> mWeakReference;
        private String path;

        public QrCodeAsyncTask(Activity activity, String path) {
            mWeakReference = new WeakReference<>(activity);
            this.path = path;
        }

        @Override
        protected String doInBackground(String... strings) {
            // 解析二维码/条码
            return QRCodeDecoder.syncDecodeQRCode(path);
        }

        @Override
        protected void onPostExecute(String s) {
            super.onPostExecute(s);
            //识别出图片二维码/条码，内容为s
            CaptureActivity activity = (CaptureActivity) mWeakReference.get();
            if (activity != null) {
                activity.handleQrCode(s);
            }
        }
    }
    /**
     * 处理图片二维码解析的数据
     * @param s
     */
    public void handleQrCode(String s) {
        if (null == s) {
            Toast.makeText(getApplicationContext(), "图片格式有误", Toast.LENGTH_SHORT).show();
        } else {
            // 识别出图片二维码/条码，内容为s
            handleResult(s);
            //Toast.makeText(getApplicationContext(), s, Toast.LENGTH_SHORT).show();
        }
    }

 private void handleResult(String result) {
        Intent intent = new Intent();
        intent.putExtra(SCAN_RESULT, result);
        setResult(Activity.RESULT_OK, intent);
        finish();
    }

其中 QRCodeDecoder 类是自己写的，是解析二维码图片的关键类，代码如下：

/**
 * @desciption: 解析二维码/条码
 */
public class QRCodeDecoder {
    public static final Map<DecodeHintType, Object> HINTS = new EnumMap<>(DecodeHintType.class);

    static {
        List<BarcodeFormat> allFormats = new ArrayList<>();
        allFormats.add(BarcodeFormat.AZTEC);
        allFormats.add(BarcodeFormat.CODABAR);
        allFormats.add(BarcodeFormat.CODE_39);
        allFormats.add(BarcodeFormat.CODE_93);
        allFormats.add(BarcodeFormat.CODE_128);
        allFormats.add(BarcodeFormat.DATA_MATRIX);
        allFormats.add(BarcodeFormat.EAN_8);
        allFormats.add(BarcodeFormat.EAN_13);
        allFormats.add(BarcodeFormat.ITF);
        allFormats.add(BarcodeFormat.MAXICODE);
        allFormats.add(BarcodeFormat.PDF_417);
        allFormats.add(BarcodeFormat.QR_CODE);
        allFormats.add(BarcodeFormat.RSS_14);
        allFormats.add(BarcodeFormat.RSS_EXPANDED);
        allFormats.add(BarcodeFormat.UPC_A);
        allFormats.add(BarcodeFormat.UPC_E);
        allFormats.add(BarcodeFormat.UPC_EAN_EXTENSION);
        HINTS.put(DecodeHintType.TRY_HARDER, BarcodeFormat.QR_CODE);
        HINTS.put(DecodeHintType.POSSIBLE_FORMATS, allFormats);
        HINTS.put(DecodeHintType.CHARACTER_SET, "utf-8");
    }

    private QRCodeDecoder() {
    }

    /**
     * 同步解析本地图片二维码。该方法是耗时操作，请在子线程中调用。
     *
     * @param picturePath 要解析的二维码图片本地路径
     * @return 返回二维码图片里的内容 或 null
     */
    public static String syncDecodeQRCode(String picturePath) {
        return syncDecodeQRCode(getDecodeAbleBitmap(picturePath));
    }

    /**
     * 同步解析bitmap二维码。该方法是耗时操作，请在子线程中调用。
     *
     * @param bitmap 要解析的二维码图片
     * @return 返回二维码图片里的内容 或 null
     */
    public static String syncDecodeQRCode(Bitmap bitmap) {
        Result result = null;
        RGBLuminanceSource source = null;
        try {
            int width = bitmap.getWidth();
            int height = bitmap.getHeight();
            int[] pixels = new int[width * height];
            bitmap.getPixels(pixels, 0, width, 0, 0, width, height);
            source = new RGBLuminanceSource(width, height, pixels);
            result = new MultiFormatReader().decode(new BinaryBitmap(new HybridBinarizer(source)), HINTS);
            return result.getText();
        } catch (Exception e) {
            e.printStackTrace();
            if (source != null) {
                try {
                    result = new MultiFormatReader().decode(new BinaryBitmap(new GlobalHistogramBinarizer(source)), HINTS);
                    return result.getText();
                } catch (Throwable e2) {
                    e2.printStackTrace();
                }
            }
            return null;
        }
    }

    /**
     * 将本地图片文件转换成可解码二维码的 Bitmap。为了避免图片太大，这里对图片进行了压缩。感谢 https://github.com/devilsen 提的 PR
     *
     * @param picturePath 本地图片文件路径
     * @return
     */
    private static Bitmap getDecodeAbleBitmap(String picturePath) {
        try {
            BitmapFactory.Options options = new BitmapFactory.Options();
            options.inJustDecodeBounds = true;
            BitmapFactory.decodeFile(picturePath, options);
            int sampleSize = options.outHeight / 400;
            if (sampleSize <= 0) {
                sampleSize = 1;
            }
            options.inSampleSize = sampleSize;
            options.inJustDecodeBounds = false;
            return BitmapFactory.decodeFile(picturePath, options);
        } catch (Exception e) {
            return null;
        }
    }

三、生成二维码图片

主要类如下所示：

/**
 * @desciption: 二维码生成
 */
public class CodeCreator {

    /**
     * 生成二维码
     */
    public static Bitmap createQRCode(String content, int w, int h, Bitmap logo) {

        if (TextUtils.isEmpty(content)) {
            return null;
        }
        /*偏移量*/
        int offsetX = w / 2;
        int offsetY = h / 2;

        /*生成logo*/
        Bitmap logoBitmap = null;

        if (logo != null) {
            Matrix matrix = new Matrix();
            float scaleFactor = Math.min(w * 1.0f / 5 / logo.getWidth(), h * 1.0f / 5 / logo.getHeight());
            matrix.postScale(scaleFactor, scaleFactor);
            logoBitmap = Bitmap.createBitmap(logo, 0, 0, logo.getWidth(), logo.getHeight(), matrix, true);
        }


        /*如果log不为null,重新计算偏移量*/
        int logoW = 0;
        int logoH = 0;
        if (logoBitmap != null) {
            logoW = logoBitmap.getWidth();
            logoH = logoBitmap.getHeight();
            offsetX = (w - logoW) / 2;
            offsetY = (h - logoH) / 2;
        }

        /*指定为UTF-8*/
        Hashtable<EncodeHintType, Object> hints = new Hashtable<EncodeHintType, Object>();
        hints.put(EncodeHintType.CHARACTER_SET, "utf-8");
        //容错级别
        hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.H);
        //设置空白边距的宽度
        hints.put(EncodeHintType.MARGIN, 0);
        // 生成二维矩阵,编码时指定大小,不要生成了图片以后再进行缩放,这样会模糊导致识别失败
        BitMatrix matrix = null;
        try {
            matrix = new MultiFormatWriter().encode(content,
                    BarcodeFormat.QR_CODE, w, h, hints);

            // 二维矩阵转为一维像素数组,也就是一直横着排了
            int[] pixels = new int[w * h];
            for (int y = 0; y < h; y++) {
                for (int x = 0; x < w; x++) {
                    if (x >= offsetX && x < offsetX + logoW && y >= offsetY && y < offsetY + logoH) {
                        int pixel = logoBitmap.getPixel(x - offsetX, y - offsetY);
                        if (pixel == 0) {
                            if (matrix.get(x, y)) {
                                pixel = 0xff000000;
                            } else {
                                pixel = 0xffffffff;
                            }
                        }
                        pixels[y * w + x] = pixel;
                    } else {
                        if (matrix.get(x, y)) {
                            pixels[y * w + x] = 0xff000000;
                        } else {
                            pixels[y * w + x] = 0xffffffff;
                        }
                    }
                }
            }

            Bitmap bitmap = Bitmap.createBitmap(w, h,
                    Bitmap.Config.ARGB_8888);
            bitmap.setPixels(pixels, 0, w, 0, 0, w, h);
            return bitmap;


        } catch (WriterException e) {

            System.out.print(e);
            return null;
        }
    }
}