我如何在此庫中更改為FRONT FACING CAMERA？

Question

我正在嘗試使用來自dlazaro66的QRCodeReaderView庫讀取QR碼，但是我遇到了一些問題，首先是在Nexus 5X等手機中，圖像顛倒顯示了，並通過添加到庫中的新方法解決了該問題，但是現在我需要將所選攝像機更改為FRONT，因為默認設置為BACK / REAR攝像機。 我該如何實現？

下一個類的代碼，謝謝。

    public class QRCodeReaderView extends SurfaceView implements SurfaceHolder.Callback,Camera.PreviewCallback {

    public interface OnQRCodeReadListener {

        public void onQRCodeRead(String text, PointF[] points);
        public void cameraNotFound();
        public void QRCodeNotFoundOnCamImage();
    }

    private OnQRCodeReadListener mOnQRCodeReadListener;

    private static final String TAG = QRCodeReaderView.class.getName();

    private QRCodeReader mQRCodeReader;
    private int mPreviewWidth;
    private int mPreviewHeight;
    private SurfaceHolder mHolder;
    private CameraManager mCameraManager;

    public QRCodeReaderView(Context context) {
        super(context);
        init();
    }

    public QRCodeReaderView(Context context, AttributeSet attrs) {
        super(context, attrs);
        init();
    }

    public void setOnQRCodeReadListener(OnQRCodeReadListener onQRCodeReadListener) {
        mOnQRCodeReadListener = onQRCodeReadListener;
    }

    public CameraManager getCameraManager() {
        return mCameraManager;
    }

    @SuppressWarnings("deprecation")
    private void init() {
        if (checkCameraHardware(getContext())){
            mCameraManager = new CameraManager(getContext());

            mHolder = this.getHolder();
            mHolder.addCallback(this);
            mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);  // Need to set this flag despite it's deprecated
        } else {
            Log.e(TAG, "Error: Camera not found");
            if (mOnQRCodeReadListener != null) {
                mOnQRCodeReadListener.cameraNotFound();
            }
        }
    }



    /****************************************************
     * SurfaceHolder.Callback,Camera.PreviewCallback
     ****************************************************/

    @Override
    public void surfaceCreated(SurfaceHolder holder) {
        try {
            // Indicate camera, our View dimensions
            mCameraManager.openDriver(holder,this.getWidth(),this.getHeight());
        } catch (IOException e) {
            Log.w(TAG, "Can not openDriver: "+e.getMessage());
            mCameraManager.closeDriver();
        }

        try {
            mQRCodeReader = new QRCodeReader();
            mCameraManager.startPreview();
        } catch (Exception e) {
            Log.e(TAG, "Exception: " + e.getMessage());
            mCameraManager.closeDriver();
        }
    }

    @Override
    public void surfaceDestroyed(SurfaceHolder holder) {
        Log.d(TAG, "surfaceDestroyed");
        mCameraManager.getCamera().setPreviewCallback(null);
        mCameraManager.getCamera().stopPreview();
        mCameraManager.getCamera().release();
        mCameraManager.closeDriver();
    }

    // Called when camera take a frame
    @Override
    public void onPreviewFrame(byte[] data, Camera camera) {

        PlanarYUVLuminanceSource source = mCameraManager.buildLuminanceSource(data, mPreviewWidth, mPreviewHeight);

        HybridBinarizer hybBin = new HybridBinarizer(source);
        BinaryBitmap bitmap = new BinaryBitmap(hybBin);

        try {
            Result result = mQRCodeReader.decode(bitmap);

            // Notify we found a QRCode
            if (mOnQRCodeReadListener != null) {
                // Transform resultPoints to View coordinates
                PointF[] transformedPoints = transformToViewCoordinates(result.getResultPoints());
                mOnQRCodeReadListener.onQRCodeRead(result.getText(), transformedPoints);
            }

        } catch (ChecksumException e) {
            Log.d(TAG, "ChecksumException");
            e.printStackTrace();
        } catch (NotFoundException e) {
            // Notify QR not found
            if (mOnQRCodeReadListener != null) {
                mOnQRCodeReadListener.QRCodeNotFoundOnCamImage();
            }
        } catch (FormatException e) {
            Log.d(TAG, "FormatException");
            e.printStackTrace();
        } finally {
            mQRCodeReader.reset();
        }
    }



    @Override
    public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
        Log.d(TAG, "surfaceChanged");

        if (mHolder.getSurface() == null){
            Log.e(TAG, "Error: preview surface does not exist");
            return;
        }

        //preview_width = width;
        //preview_height = height;

        mPreviewWidth = mCameraManager.getPreviewSize().x;
        mPreviewHeight = mCameraManager.getPreviewSize().y;


        mCameraManager.stopPreview();
        mCameraManager.getCamera().setPreviewCallback(this);
        mCameraManager.getCamera().setDisplayOrientation(90); // Portrait mode

        // Fix the camera sensor rotation
        setCameraDisplayOrientation(this.getContext(), mCameraManager.getCamera());

        mCameraManager.startPreview();
    }

    /**
     * Transform result to surfaceView coordinates
     *
     * This method is needed because coordinates are given in landscape camera coordinates.
     * Now is working but transform operations aren't very explained
     *
     * TODO re-write this method explaining each single value
     *
     * @return a new PointF array with transformed points
     */
    private PointF[] transformToViewCoordinates(ResultPoint[] resultPoints) {

        PointF[] transformedPoints = new PointF[resultPoints.length];
        int index = 0;
        if (resultPoints != null){
            float previewX = mCameraManager.getPreviewSize().x;
            float previewY = mCameraManager.getPreviewSize().y;
            float scaleX = this.getWidth()/previewY;
            float scaleY = this.getHeight()/previewX;

            for (ResultPoint point :resultPoints){
                PointF tmppoint = new PointF((previewY- point.getY())*scaleX, point.getX()*scaleY);
                transformedPoints[index] = tmppoint;
                index++;
            }
        }
        return transformedPoints;

    }


    /** Check if this device has a camera */
    private boolean checkCameraHardware(Context context) {
        if (context.getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA)){
            // this device has a camera
            return true;
        }
        else if (context.getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA_FRONT)){
            // this device has a front camera
            return true;
        }
        else if (context.getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA_ANY)){
            // this device has any camera
            return true;
        }
        else {
            // no camera on this device
            return false;
        }
    }

    /**
     * Fix for the camera Sensor no some devices (ex.: Nexus 5x)
     * https://developer.android.com/reference/android/hardware/Camera.html#setDisplayOrientation(int)
     */
    @SuppressWarnings("deprecation")
    public static void setCameraDisplayOrientation(Context context, android.hardware.Camera camera) {
        if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.GINGERBREAD) {
            Camera.CameraInfo info = new Camera.CameraInfo();
            android.hardware.Camera.getCameraInfo(0, info);
            WindowManager windowManager = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);
            int rotation = windowManager.getDefaultDisplay().getRotation();
            int degrees = 0;
            switch (rotation) {
                case Surface.ROTATION_0: degrees = 0; break;
                case Surface.ROTATION_90: degrees = 90; break;
                case Surface.ROTATION_180: degrees = 180; break;
                case Surface.ROTATION_270: degrees = 270; break;
            }

            int result;
            if (info.facing == Camera.CameraInfo.CAMERA_FACING_FRONT) {
                result = (info.orientation + degrees) % 360;
                result = (360 - result) % 360;  // compensate the mirror
            } else {  // back-facing
                result = (info.orientation - degrees + 360) % 360;
            }
            camera.setDisplayOrientation(result);
        }
    }

}

Answer 1

您必須更改CameraManager.openCamera（）方法。

Answer 2

2.0.0及更高版本現在具有此功能。 請將您的庫更新到最新的https://github.com/dlazaro66/QRCodeReaderView#add-it-to-your-project

並使用以下兩種方法選擇您要打開的相機：

mydecoderview.setFrontCamera();

mydecoderview.setBackCamera();

您還可以使用ID指定攝像機

public void setPreviewCameraId(int cameraId)