我正在尝试使用库QRCodeReaderView from dlazaro66来读取QR码，但我遇到了一些问题，首先是在像Nexus 5X这样的手机中，图像是颠倒显示的，用新方法解决添加到库中，但现在我需要将选定的摄像机更改为FRONT，因为默认是BACK / REAR摄像机。我怎么能做到这一点？
下一个班级的代码，谢谢。
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);
}
}
}
答案 0 :(得分：1)
您必须更改 CameraManager.openCamera（）方法。
答案 1 :(得分：0)
版本2.0.0及更高版本现在具有此功能。请将您的资料库更新为最新的https://github.com/dlazaro66/QRCodeReaderView#add-it-to-your-project
并使用这2种方法选择您要打开的相机：
mydecoderview.setFrontCamera();
mydecoderview.setBackCamera();
您还可以使用ID
指定相机 public void setPreviewCameraId(int cameraId)