一、应用背景

小白公司业务为车辆安全驾驶检测等，需要开启相机将图像传递给算法进行处理以达到行车预警的功能。由于项目需求，需要将开启相机这一块由原来的Camera1.0更新为Camera2.0，以下是小白开发中所遇到的问题与解决方案，仅供参考。

二、Camera2.0学习

1、Google官方demo

官方demo地址：android-Camera2Basic

2、流程

这里引用了管道的概念将安卓设备和摄像头之间联通起来，系统向摄像头发送 Capture 请求，而摄像头会返回 CameraMetadata。这一切建立在一个叫作 CameraCaptureSession 的会话中。

三、实践

1、申请权限

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

Android 6.0以上需要进行权限的动态申请。

2、Camera2.0工具类

public class Camera2Proxy {private static final String TAG = "Camera2Proxy";private Activity mActivity;private int mCameraId = CameraCharacteristics.LENS_FACING_FRONT; // 要打开的摄像头IDprivate Size mPreviewSize; // 预览大小private CameraManager mCameraManager; // 相机管理者private CameraCharacteristics mCameraCharacteristics; // 相机属性private CameraDevice mCameraDevice; // 相机对象private CameraCaptureSession mCaptureSession;private CaptureRequest.Builder mPreviewRequestBuilder; // 相机预览请求的构造器private Semaphore mCameraOpenCloseLock = new Semaphore(1);//一个信号量以防止应用程序在关闭相机之前退出。private CaptureRequest mPreviewRequest;private Handler mBackgroundHandler;private HandlerThread mBackgroundThread;private ImageReader mImageReader;private Surface mPreviewSurface;private SurfaceTexture mPreviewSurfaceTexture;private OrientationEventListener mOrientationEventListener;private int mDisplayRotate = 0;private int mDeviceOrientation = 0; // 设备方向，由相机传感器获取private int mZoom = 1; // 缩放public static int CameraFPS = 0; // 帧率private int frameCount = 0;private long frameTime = SystemClock.elapsedRealtime();public long mLastPreviewFrameTime = SystemClock.elapsedRealtime(); // 最后一帧数据的时间private byte[] data = null;private boolean mStop = true;private final Object lock = new Object();private YuvCroper yuvCroper;private int cropH = 0;  //剪裁图像后的高度private DataSendThread mDataSendThread;private MediaRecorder mediaRecorder;private long startRecordTime = 0;// 录像开启时间private static final int SENSOR_ORIENTATION_DEFAULT_DEGREES = 90;private static final int SENSOR_ORIENTATION_INVERSE_DEGREES = 270;public static final int MEDIA_QUALITY_HIGH = 30 * 100000;private int rotation;private boolean isRecording = false;private String filePath;private static final SparseIntArray DEFAULT_ORIENTATIONS = new SparseIntArray();private static final SparseIntArray INVERSE_ORIENTATIONS = new SparseIntArray();static {DEFAULT_ORIENTATIONS.append(Surface.ROTATION_0, 90);DEFAULT_ORIENTATIONS.append(Surface.ROTATION_90, 0);DEFAULT_ORIENTATIONS.append(Surface.ROTATION_180, 270);DEFAULT_ORIENTATIONS.append(Surface.ROTATION_270, 180);}static {INVERSE_ORIENTATIONS.append(Surface.ROTATION_0, 270);INVERSE_ORIENTATIONS.append(Surface.ROTATION_90, 180);INVERSE_ORIENTATIONS.append(Surface.ROTATION_180, 90);INVERSE_ORIENTATIONS.append(Surface.ROTATION_270, 0);}/*** 打开摄像头的回调*/private CameraDevice.StateCallback mStateCallback = new CameraDevice.StateCallback() {@Overridepublic void onOpened(@NonNull CameraDevice camera) {Log.d(TAG, "onOpened");mCameraOpenCloseLock.release();mCameraDevice = camera;int recordState = (int) SPUtils.get(mActivity, SPUtils.SP_RECORD_STATE, 0);if (recordState == 1) {initRecordPreviewRequest();} else {initPreviewRequest();}}@Overridepublic void onDisconnected(@NonNull CameraDevice camera) {Log.d(TAG, "onDisconnected");mCameraOpenCloseLock.release();releaseCamera();}@Overridepublic void onError(@NonNull CameraDevice camera, int error) {Log.e(TAG, "Camera Open failed, error: " + error);mCameraOpenCloseLock.release();releaseCamera();}};/*** 图像回调处理*/private final ImageReader.OnImageAvailableListener mOnImageAvailableListener = new ImageReader.OnImageAvailableListener() {@Overridepublic void onImageAvailable(ImageReader reader) {Image image = reader.acquireLatestImage();if (image != null) {if (!mStop) {synchronized (lock) {data = ImageUtils.getBytesFromImageAsType(image, ImageUtils.YV12);}}image.close();}frameCount++;mLastPreviewFrameTime = SystemClock.elapsedRealtime();//记录帧率if (mLastPreviewFrameTime - frameTime >= 1000) {CameraFPS = frameCount;Log.e(TAG, "fps = " + CameraFPS);frameCount = 0;frameTime = mLastPreviewFrameTime;}}};@TargetApi(Build.VERSION_CODES.M)public Camera2Proxy(Activity activity) {mActivity = activity;mCameraManager = (CameraManager) mActivity.getSystemService(Context.CAMERA_SERVICE);try {//按照16:9的比例剪裁，剪裁后的图像尺寸不能是奇数，处理各个数据为4的倍数RectF rectF = new RectF(0, ((16.0f * MediaInfo.PRIVIEW_WIDTH - 9.0f * MediaInfo.PRIVIEW_HEIGHT) / (32.0f * MediaInfo.PRIVIEW_WIDTH)), 1, ((16.0f * MediaInfo.PRIVIEW_WIDTH + 9.0f * MediaInfo.PRIVIEW_HEIGHT) / (32.0f * MediaInfo.PRIVIEW_WIDTH)));Log.e("YuvCroper", "MediaInfo.PRIVIEW_WIDTH = " + MediaInfo.PRIVIEW_WIDTH + " MediaInfo.PRIVIEW_HEIGHT=" + MediaInfo.PRIVIEW_HEIGHT + " rectF=" + rectF.toString());yuvCroper = new YuvCroper(YuvCroper.YUV_420P, MediaInfo.PRIVIEW_HEIGHT, MediaInfo.PRIVIEW_WIDTH, rectF);} catch (Exception e) {e.printStackTrace();}mOrientationEventListener = new OrientationEventListener(mActivity) {@Overridepublic void onOrientationChanged(int orientation) {mDeviceOrientation = orientation;}};}@SuppressLint("MissingPermission")public void openCamera(int width, int height) {Log.v(TAG, "openCamera");startBackgroundThread(); // 对应 releaseCamera() 方法中的 stopBackgroundThread()mOrientationEventListener.enable();try {if (!mCameraOpenCloseLock.tryAcquire(2500, TimeUnit.MILLISECONDS)) {throw new RuntimeException("Time out waiting to lock camera opening.");}try {mCameraCharacteristics = mCameraManager.getCameraCharacteristics(Integer.toString(0));StreamConfigurationMap map = mCameraCharacteristics.get(CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP);// 拍照大小，选择能支持的一个最大的图片大小mImageReader = ImageReader.newInstance(MediaInfo.PRIVIEW_WIDTH, MediaInfo.PRIVIEW_HEIGHT, ImageFormat.YUV_420_888, 2);mImageReader.setOnImageAvailableListener(   // 设置监听和后台线程处理器mOnImageAvailableListener, null);// 预览大小，根据上面选择的拍照图片的长宽比，选择一个和控件长宽差不多的大小mPreviewSize = chooseOptimalSize(map.getOutputSizes(SurfaceTexture.class), width, height, MediaInfo.PRIVIEW_WIDTH, MediaInfo.PRIVIEW_HEIGHT);Log.d(TAG, "preview size: " + mPreviewSize.getWidth() + "*" + mPreviewSize.getHeight());// 打开摄像头mCameraManager.openCamera(Integer.toString(0), mStateCallback, mBackgroundHandler);startSendDataThread();} catch (Exception e) {Log.e(TAG,"No current camera was found!");e.printStackTrace();}} catch (Exception e) {e.printStackTrace();}}/*** 关闭摄像头*/public void releaseCamera() {Log.v(TAG, "releaseCamera");try {if (isRecording) {isRecording = false;if (mediaRecorder != null) {mediaRecorder.stop();mediaRecorder.reset();mediaRecorder.release();if (null != SDCardUtils.getInsSDCardPath()) {long end = System.currentTimeMillis();long duration = end - startRecordTime;SQLiteFactory.getInstance().getFileDao().insertFileEntity(startRecordTime, end, 3, (int) duration, 0);}}/** 生成录像对应缩略图*/if (null != filePath && null != SDCardUtils.getInsSDCardPath()) {ImageUtils.saveThumbnail2(filePath);filePath = null;}}if (null != mCaptureSession) {mCaptureSession.close();mCaptureSession = null;}if (mCameraDevice != null) {mCameraDevice.close();mCameraDevice = null;}if (mImageReader != null) {mImageReader.close();mImageReader = null;}mOrientationEventListener.disable();stopBackgroundThread(); // 对应 openCamera() 方法中的 startBackgroundThread()} catch (Exception e) {e.printStackTrace();}}/*** 设置预览的surface* @param surfaceTexture*/public void setPreviewSurface(SurfaceTexture surfaceTexture) {mPreviewSurfaceTexture = surfaceTexture;}/*** 预览初始化*/private void initPreviewRequest() {try {mPreviewRequestBuilder = mCameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW);if (mPreviewSurfaceTexture != null && mPreviewSurface == null) { // use texture viewmPreviewSurfaceTexture.setDefaultBufferSize(mPreviewSize.getWidth(), mPreviewSize.getHeight());mPreviewSurface = new Surface(mPreviewSurfaceTexture);}final Range<Integer>[] fpsRanges = mCameraCharacteristics.get(CameraCharacteristics.CONTROL_AE_AVAILABLE_TARGET_FPS_RANGES);Log.e(TAG, "SYNC_MAX_LATENCY_PER_FRAME_CONTROL: " + Arrays.toString(fpsRanges));mPreviewRequestBuilder.addTarget(mPreviewSurface); // 设置预览输出的 SurfacemPreviewRequestBuilder.addTarget(mImageReader.getSurface());mCameraDevice.createCaptureSession(Arrays.asList(mPreviewSurface, mImageReader.getSurface()),new CameraCaptureSession.StateCallback() {@Overridepublic void onConfigured(@NonNull CameraCaptureSession session) {mCaptureSession = session;mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AE_TARGET_FPS_RANGE, fpsRanges[fpsRanges.length - 1]);// 设置连续自动对焦mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AF_MODE, CaptureRequest.CONTROL_AE_ANTIBANDING_MODE_AUTO);
//                            // 设置自动曝光
//                            mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AE_MODE, CaptureRequest
//                                    .CONTROL_AE_MODE_ON_AUTO_FLASH);// 设置完后自动开始预览mPreviewRequest = mPreviewRequestBuilder.build();startPreview();}@Overridepublic void onConfigureFailed(@NonNull CameraCaptureSession session) {Log.e(TAG, "ConfigureFailed. session: mCaptureSession");}}, null); // handle 传入 null 表示使用当前线程的 Looper} catch (CameraAccessException e) {e.printStackTrace();}}/*** 预览并录像*/private void initRecordPreviewRequest() {if (mCameraDevice == null || mPreviewSurfaceTexture == null) {return;}try {setUpMediaRecorder();mPreviewRequestBuilder = mCameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW);mPreviewSurfaceTexture.setDefaultBufferSize(mPreviewSize.getWidth(), mPreviewSize.getHeight());mPreviewSurface = new Surface(mPreviewSurfaceTexture);mPreviewRequestBuilder.addTarget(mPreviewSurface);mPreviewRequestBuilder.addTarget(mImageReader.getSurface());//设置ImageReader为输出Surface// Set up Surface for the MediaRecordermPreviewRequestBuilder.addTarget(mediaRecorder.getSurface());//设置MediaRecorder为输出SurfacemCameraDevice.createCaptureSession(Arrays.asList(mPreviewSurface, mImageReader.getSurface(), mediaRecorder.getSurface()),new CameraCaptureSession.StateCallback() {@Overridepublic void onConfigured(@NonNull CameraCaptureSession cameraCaptureSession) {mCaptureSession = cameraCaptureSession;updatePreview(mPreviewRequestBuilder);mediaRecorder.start();isRecording = true;}@Overridepublic void onConfigureFailed(@NonNull CameraCaptureSession cameraCaptureSession) {Log.e(TAG, "ConfigureFailed. session: mCaptureSession");}}, mBackgroundHandler);} catch (CameraAccessException e) {e.printStackTrace();}}/*** 设置录像*/private void setUpMediaRecorder() {try {if (mediaRecorder == null) {mediaRecorder = new MediaRecorder();}mediaRecorder.setAudioSource(MediaRecorder.AudioSource.MIC);mediaRecorder.setVideoSource(MediaRecorder.VideoSource.SURFACE);mediaRecorder.setOutputFormat(MediaRecorder.OutputFormat.MPEG_4);startRecordTime = System.currentTimeMillis();filePath = AppUtils.VIDEO_PREFIX + DateUtils.millisecondToDate2(startRecordTime) + ".mp4";File targetFile = new File(filePath);Log.e(TAG, targetFile.getAbsolutePath());mediaRecorder.setAudioEncoder(MediaRecorder.AudioEncoder.AAC);mediaRecorder.setVideoEncoder(MediaRecorder.VideoEncoder.H264);mediaRecorder.setVideoSize(MediaInfo.PRIVIEW_WIDTH, MediaInfo.PRIVIEW_HEIGHT);mediaRecorder.setVideoFrameRate(30);mediaRecorder.setOutputFile(targetFile.getAbsolutePath());mediaRecorder.setVideoEncodingBitRate(MEDIA_QUALITY_HIGH);switch (mDeviceOrientation) {case SENSOR_ORIENTATION_DEFAULT_DEGREES:mediaRecorder.setOrientationHint(DEFAULT_ORIENTATIONS.get(rotation));break;case SENSOR_ORIENTATION_INVERSE_DEGREES:mediaRecorder.setOrientationHint(INVERSE_ORIENTATIONS.get(rotation));break;}mediaRecorder.prepare();} catch (Exception e) {e.printStackTrace();}}/*** 开启预览*/public void startPreview() {Log.v(TAG, "startPreview");int bufSize = MediaInfo.PRIVIEW_WIDTH * MediaInfo.PRIVIEW_HEIGHT * 3 / 2;data = new byte[bufSize];if (mCaptureSession == null || mPreviewRequestBuilder == null) {Log.w(TAG, "startPreview: mCaptureSession or mPreviewRequestBuilder is null");return;}try {// 开始预览，即一直发送预览的请求mCaptureSession.setRepeatingRequest(mPreviewRequest, null, mBackgroundHandler);} catch (CameraAccessException e) {e.printStackTrace();}}/*** 更新预览画面* @param recordBuilder*/private void updatePreview(CaptureRequest.Builder recordBuilder) {if (null == mCameraDevice) {return;}try {setUpCaptureRequestBuilder(recordBuilder);HandlerThread thread = new HandlerThread("CameraPreview");thread.start();mCaptureSession.setRepeatingRequest(recordBuilder.build(), null, mBackgroundHandler);} catch (CameraAccessException e) {e.printStackTrace();}}private void setUpCaptureRequestBuilder(CaptureRequest.Builder requestBuilder) {requestBuilder.set(CaptureRequest.CONTROL_MODE, CameraMetadata.CONTROL_MODE_AUTO);}public void stopPreview() {Log.v(TAG, "stopPreview");if (mCaptureSession == null || mPreviewRequestBuilder == null) {Log.w(TAG, "stopPreview: mCaptureSession or mPreviewRequestBuilder is null");return;}try {mCaptureSession.stopRepeating();} catch (CameraAccessException e) {e.printStackTrace();}}/*** 拍照*/public void captureStillPicture() {try {CaptureRequest.Builder captureBuilder = mCameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_STILL_CAPTURE);captureBuilder.addTarget(mImageReader.getSurface());captureBuilder.set(CaptureRequest.CONTROL_AF_MODE, CaptureRequest.CONTROL_AF_MODE_CONTINUOUS_PICTURE);captureBuilder.set(CaptureRequest.JPEG_ORIENTATION, getJpegOrientation(mDeviceOrientation));// 预览如果有放大，拍照的时候也应该保存相同的缩放Rect zoomRect = mPreviewRequestBuilder.get(CaptureRequest.SCALER_CROP_REGION);if (zoomRect != null) {captureBuilder.set(CaptureRequest.SCALER_CROP_REGION, zoomRect);}mCaptureSession.stopRepeating();mCaptureSession.abortCaptures();final long time = System.currentTimeMillis();mCaptureSession.capture(captureBuilder.build(), new CameraCaptureSession.CaptureCallback() {@Overridepublic void onCaptureCompleted(@NonNull CameraCaptureSession session,@NonNull CaptureRequest request,@NonNull TotalCaptureResult result) {Log.w(TAG, "onCaptureCompleted, time: " + (System.currentTimeMillis() - time));try {mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AF_TRIGGER, CameraMetadata.CONTROL_AF_TRIGGER_CANCEL);mCaptureSession.capture(mPreviewRequestBuilder.build(), null, mBackgroundHandler);} catch (CameraAccessException e) {e.printStackTrace();}startPreview();}}, mBackgroundHandler);} catch (CameraAccessException e) {e.printStackTrace();}}/*** 获取拍照时的角度* @param deviceOrientation* @return*/private int getJpegOrientation(int deviceOrientation) {if (deviceOrientation == OrientationEventListener.ORIENTATION_UNKNOWN) return 0;int sensorOrientation = mCameraCharacteristics.get(CameraCharacteristics.SENSOR_ORIENTATION);// Round device orientation to a multiple of 90deviceOrientation = (deviceOrientation + 45) / 90 * 90;// Reverse device orientation for front-facing camerasboolean facingFront = mCameraCharacteristics.get(CameraCharacteristics.LENS_FACING) == CameraCharacteristics.LENS_FACING_FRONT;if (facingFront) deviceOrientation = -deviceOrientation;// Calculate desired JPEG orientation relative to camera orientation to make// the image upright relative to the device orientationint jpegOrientation = (sensorOrientation + deviceOrientation + 360) % 360;Log.d(TAG, "jpegOrientation: " + jpegOrientation);return jpegOrientation;}/*** 是否为前置摄像头* @return*/public boolean isFrontCamera() {return mCameraId == CameraCharacteristics.LENS_FACING_BACK;}/*** 获取预览尺寸* @return*/public Size getPreviewSize() {return mPreviewSize;}/*** 切换摄像头* @param width* @param height*/public void switchCamera(int width, int height) {mCameraId ^= 1;Log.d(TAG, "switchCamera: mCameraId: " + mCameraId);releaseCamera();openCamera(width, height);}/*** 获取合适的尺寸* @param sizes* @param viewWidth* @param viewHeight* @param previewWidth* @param previewHeight* @return*/private Size chooseOptimalSize(Size[] sizes, int viewWidth, int viewHeight, int previewWidth, int previewHeight) {int totalRotation = getRotation();boolean swapRotation = totalRotation == 90 || totalRotation == 270;int width = swapRotation ? viewHeight : viewWidth;int height = swapRotation ? viewWidth : viewHeight;return getSuitableSize(sizes, width, height, previewWidth, previewHeight);}/*** 获取翻转角度* @return*/private int getRotation() {int displayRotation = 0;rotation = mActivity.getWindowManager().getDefaultDisplay().getRotation();switch (rotation) {case Surface.ROTATION_0:displayRotation = 90;break;case Surface.ROTATION_90:displayRotation = 0;break;case Surface.ROTATION_180:displayRotation = 270;break;case Surface.ROTATION_270:displayRotation = 180;break;}int sensorOrientation = mCameraCharacteristics.get(CameraCharacteristics.SENSOR_ORIENTATION);mDisplayRotate = (displayRotation + sensorOrientation + 270) % 360;return mDisplayRotate;}/*** 获取相机与屏幕支持的最大尺寸* @param sizes* @param width* @param height* @param previewWidth* @param previewHeight* @return*/private Size getSuitableSize(Size[] sizes, int width, int height, int previewWidth, int previewHeight) {int minDelta = Integer.MAX_VALUE; // 最小的差值，初始值应该设置大点保证之后的计算中会被重置int index = 0; // 最小的差值对应的索引坐标float aspectRatio = previewHeight * 1.0f / previewWidth;Log.d(TAG, "getSuitableSize. aspectRatio: " + aspectRatio);for (int i = 0; i < sizes.length; i++) {Size size = sizes[i];Log.e(TAG, "width: " + size.getWidth() + ", height: " + size.getHeight());// 先判断比例是否相等if (size.getWidth() * aspectRatio == size.getHeight()) {int delta = Math.abs(width - size.getWidth());if (delta == 0) {return size;}if (minDelta > delta) {minDelta = delta;index = i;}}}return sizes[index];}/*** 预览画面缩放* @param isZoomIn*/public void handleZoom(boolean isZoomIn) {if (mCameraDevice == null || mCameraCharacteristics == null || mPreviewRequestBuilder == null) {return;}int maxZoom = mCameraCharacteristics.get(CameraCharacteristics.SCALER_AVAILABLE_MAX_DIGITAL_ZOOM).intValue()* 10;Log.d(TAG, "handleZoom: maxZoom: " + maxZoom);Rect rect = mCameraCharacteristics.get(CameraCharacteristics.SENSOR_INFO_ACTIVE_ARRAY_SIZE);if (isZoomIn && mZoom < maxZoom) {mZoom++;} else if (mZoom > 1) {mZoom--;}Log.d(TAG, "handleZoom: mZoom: " + mZoom);int minW = rect.width() / maxZoom;int minH = rect.height() / maxZoom;int difW = rect.width() - minW;int difH = rect.height() - minH;int cropW = difW * mZoom / 100;int cropH = difH * mZoom / 100;cropW -= cropW & 3;cropH -= cropH & 3;Log.d(TAG, "handleZoom: cropW: " + cropW + ", cropH: " + cropH);Rect zoomRect = new Rect(cropW, cropH, rect.width() - cropW, rect.height() - cropH);mPreviewRequestBuilder.set(CaptureRequest.SCALER_CROP_REGION, zoomRect);mPreviewRequest = mPreviewRequestBuilder.build();startPreview(); // 需要重新 start preview 才能生效}/*** 点击对焦* @param x* @param y* @param width* @param height*/public void focusOnPoint(double x, double y, int width, int height) {if (mCameraDevice == null || mPreviewRequestBuilder == null) {return;}// 1. 先取相对于view上面的坐标int previewWidth = mPreviewSize.getWidth();int previewHeight = mPreviewSize.getHeight();if (mDisplayRotate == 90 || mDisplayRotate == 270) {previewWidth = mPreviewSize.getHeight();previewHeight = mPreviewSize.getWidth();}// 2. 计算摄像头取出的图像相对于view放大了多少，以及有多少偏移double tmp;double imgScale;double verticalOffset = 0;double horizontalOffset = 0;if (previewHeight * width > previewWidth * height) {imgScale = width * 1.0 / previewWidth;verticalOffset = (previewHeight - height / imgScale) / 2;} else {imgScale = height * 1.0 / previewHeight;horizontalOffset = (previewWidth - width / imgScale) / 2;}// 3. 将点击的坐标转换为图像上的坐标x = x / imgScale + horizontalOffset;y = y / imgScale + verticalOffset;if (90 == mDisplayRotate) {tmp = x;x = y;y = mPreviewSize.getHeight() - tmp;} else if (270 == mDisplayRotate) {tmp = x;x = mPreviewSize.getWidth() - y;y = tmp;}// 4. 计算取到的图像相对于裁剪区域的缩放系数，以及位移Rect cropRegion = mPreviewRequestBuilder.get(CaptureRequest.SCALER_CROP_REGION);if (cropRegion == null) {Log.w(TAG, "can't get crop region");cropRegion = mCameraCharacteristics.get(CameraCharacteristics.SENSOR_INFO_ACTIVE_ARRAY_SIZE);}int cropWidth = cropRegion.width();int cropHeight = cropRegion.height();if (mPreviewSize.getHeight() * cropWidth > mPreviewSize.getWidth() * cropHeight) {imgScale = cropHeight * 1.0 / mPreviewSize.getHeight();verticalOffset = 0;horizontalOffset = (cropWidth - imgScale * mPreviewSize.getWidth()) / 2;} else {imgScale = cropWidth * 1.0 / mPreviewSize.getWidth();horizontalOffset = 0;verticalOffset = (cropHeight - imgScale * mPreviewSize.getHeight()) / 2;}// 5. 将点击区域相对于图像的坐标，转化为相对于成像区域的坐标x = x * imgScale + horizontalOffset + cropRegion.left;y = y * imgScale + verticalOffset + cropRegion.top;double tapAreaRatio = 0.1;Rect rect = new Rect();rect.left = clamp((int) (x - tapAreaRatio / 2 * cropRegion.width()), 0, cropRegion.width());rect.right = clamp((int) (x + tapAreaRatio / 2 * cropRegion.width()), 0, cropRegion.width());rect.top = clamp((int) (y - tapAreaRatio / 2 * cropRegion.height()), 0, cropRegion.height());rect.bottom = clamp((int) (y + tapAreaRatio / 2 * cropRegion.height()), 0, cropRegion.height());// 6. 设置 AF、AE 的测光区域，即上述得到的 rectmPreviewRequestBuilder.set(CaptureRequest.CONTROL_AF_REGIONS, new MeteringRectangle[]{new MeteringRectangle(rect, 1000)});mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AE_REGIONS, new MeteringRectangle[]{new MeteringRectangle(rect, 1000)});mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AF_MODE, CaptureRequest.CONTROL_AF_MODE_AUTO);mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AF_TRIGGER, CameraMetadata.CONTROL_AF_TRIGGER_START);mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AE_PRECAPTURE_TRIGGER, CameraMetadata.CONTROL_AE_PRECAPTURE_TRIGGER_START);try {// 7. 发送上述设置的对焦请求，并监听回调mCaptureSession.capture(mPreviewRequestBuilder.build(), mAfCaptureCallback, mBackgroundHandler);} catch (CameraAccessException e) {e.printStackTrace();}}private final CameraCaptureSession.CaptureCallback mAfCaptureCallback = new CameraCaptureSession.CaptureCallback() {private void process(CaptureResult result) {Integer state = result.get(CaptureResult.CONTROL_AF_STATE);if (null == state) {return;}Log.d(TAG, "process: CONTROL_AF_STATE: " + state);if (state == CaptureResult.CONTROL_AF_STATE_FOCUSED_LOCKED || state == CaptureResult.CONTROL_AF_STATE_NOT_FOCUSED_LOCKED) {Log.d(TAG, "process: start normal preview");mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AF_TRIGGER, CameraMetadata.CONTROL_AF_TRIGGER_CANCEL);mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AF_MODE, CaptureRequest.CONTROL_AF_MODE_CONTINUOUS_PICTURE);mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AE_MODE, CaptureRequest.FLASH_MODE_OFF);startPreview();}}@Overridepublic void onCaptureProgressed(@NonNull CameraCaptureSession session,@NonNull CaptureRequest request,@NonNull CaptureResult partialResult) {process(partialResult);}@Overridepublic void onCaptureCompleted(@NonNull CameraCaptureSession session,@NonNull CaptureRequest request,@NonNull TotalCaptureResult result) {process(result);}};private void startBackgroundThread() {if (mBackgroundThread == null || mBackgroundHandler == null) {Log.v(TAG, "startBackgroundThread");mStop = false;mBackgroundThread = new HandlerThread("CameraBackground");mBackgroundThread.start();mBackgroundHandler = new Handler(mBackgroundThread.getLooper());}}/***  开启数据发送线程*/private void startSendDataThread() {if (mDataSendThread == null) {mDataSendThread = new DataSendThread();mDataSendThread.start();mStop = false;}}private void stopBackgroundThread() {Log.v(TAG, "stopBackgroundThread");mBackgroundThread.quitSafely();try {mStop = true;mBackgroundThread.join();mBackgroundThread = null;mBackgroundHandler = null;} catch (InterruptedException e) {e.printStackTrace();}}private int clamp(int x, int min, int max) {if (x > max) return max;if (x < min) return min;return x;}/***  实时回调数据下发C层线程*/class DataSendThread extends Thread {public DataSendThread() {super("Camera DataSendThread");}@Overridepublic void run() {// TODO Auto-generated method stubandroid.os.Process.setThreadPriority(android.os.Process.THREAD_PRIORITY_URGENT_AUDIO);Thread.currentThread().setPriority(Thread.MAX_PRIORITY);long curFrameBegingTime = 0;long curFrameTimeout = 0;while (!mStop) {try {curFrameBegingTime = SystemClock.elapsedRealtimeNanos();while (data == null && !mStop)ThreadUtils.sleep(10);if (mStop)break;if (data != null) {if (Constants.PORTRAIT_MODE) {byte[] rotate90 = new byte[data.length];rotateYv12Degree90(data,MediaInfo.PRIVIEW_WIDTH,MediaInfo.PRIVIEW_HEIGHT,rotate90,true);byte[] cut = yuvCroper.crop(rotate90);if (cut[0] != 0)JniInterface.SendVideoData(cut,MediaInfo.PRIVIEW_HEIGHT, cropH, 0);if (GloableConfig.getInstance().getRecordState() == Constants.STATUS_ENABLE&& null != JMediaRecorder.getInstance().getmMediaRecorder()&& null != JMediaRecorder.getInstance().getmMediaRecorder().getVideoEncoder()) {VideoEncoder.onPreviewCallbackWithBuffer(rotate90, 0);}} else {JniInterface.SendVideoData(data,MediaInfo.PRIVIEW_WIDTH, MediaInfo.PRIVIEW_HEIGHT, 0);if (GloableConfig.getInstance().getRecordState() == Constants.STATUS_ENABLE&& null != JMediaRecorder.getInstance().getmMediaRecorder()&& null != JMediaRecorder.getInstance().getmMediaRecorder().getVideoEncoder()) {VideoEncoder.onPreviewCallbackWithBuffer(data, 0);}}}long left = 1000000000/ MediaInfo.PRIVIEW_FRAME_RATE- (SystemClock.elapsedRealtimeNanos() - curFrameBegingTime);if (left > 0) {left -= curFrameTimeout;curFrameTimeout = 0;if (left > 0)ThreadUtils.sleep(left / 1000000,(int) (left % 1000000));} elsecurFrameTimeout = -left;} catch (Exception e) {e.printStackTrace();}}}}private void rotateYv12Degree90(byte[] src, int width, int height, byte[] dst, boolean clockwise) {int area = width * height;if (clockwise) {rotateRectClockwiseDegree90(src, 0, width, height, dst, 0);rotateRectClockwiseDegree90(src, area, width / 2, height / 2, dst, area);rotateRectClockwiseDegree90(src, area * 5 / 4, width / 2, height / 2, dst, area * 5 / 4);} else {rotateRectAnticlockwiseDegree90(src, 0, width, height, dst, 0);rotateRectAnticlockwiseDegree90(src, area, width / 2, height / 2, dst, area);rotateRectAnticlockwiseDegree90(src, area * 5 / 4, width / 2, height / 2, dst, area * 5 / 4);}}private void rotateRectClockwiseDegree90(byte[] src, int srcOffset, int width, int height, byte dst[], int dstOffset) {int i, j;int index = dstOffset;for (i = 0; i < width; i++) {for (j = height - 1; j >= 0; j--) {dst[index] = src[srcOffset + j * width + i];index++;}}}private void rotateRectAnticlockwiseDegree90(byte[] src, int srcOffset, int width, int height, byte dst[],int dstOffset) {int i, j;int index = dstOffset;for (i = width - 1; i >= 0; i--) {for (j = 0; j < height; j++) {dst[index] = src[srcOffset + j * width + i];index++;}}}
}

3.0回调的数据处理

/**** 此方法内注释以640*480为例* 未考虑CropRect的*/public static byte[] getBytesFromImageAsType(Image image, int type) {try {//获取源数据，如果是YUV格式的数据planes.length = 3//plane[i]里面的实际数据可能存在byte[].length <= capacity (缓冲区总大小)final Image.Plane[] planes = image.getPlanes();//数据有效宽度，一般的，图片width <= rowStride，这也是导致byte[].length <= capacity的原因// 所以我们只取width部分int width = image.getWidth();int height = image.getHeight();//此处用来装填最终的YUV数据，需要1.5倍的图片大小，因为Y U V 比例为 4:1:1byte[] yuvBytes = new byte[width * height * ImageFormat.getBitsPerPixel(ImageFormat.YV12) / 8];//目标数组的装填到的位置int dstIndex = 0;//临时存储uv数据的byte uBytes[] = new byte[width * height / 4];byte vBytes[] = new byte[width * height / 4];int uIndex = 0;int vIndex = 0;int pixelsStride, rowStride;for (int i = 0; i < planes.length; i++) {pixelsStride = planes[i].getPixelStride();rowStride = planes[i].getRowStride();ByteBuffer buffer = planes[i].getBuffer();//如果pixelsStride==2，一般的Y的buffer长度=640*480，UV的长度=640*480/2-1//源数据的索引，y的数据是byte中连续的，u的数据是v向左移以为生成的，两者都是偶数位为有效数据byte[] bytes = new byte[buffer.capacity()];buffer.get(bytes);int srcIndex = 0;if (i == 0) {//直接取出来所有Y的有效区域，也可以存储成一个临时的bytes，到下一步再copyfor (int j = 0; j < height; j++) {System.arraycopy(bytes, srcIndex, yuvBytes, dstIndex, width);srcIndex += rowStride;dstIndex += width;}} else if (i == 1) {//根据pixelsStride取相应的数据for (int j = 0; j < height / 2; j++) {for (int k = 0; k < width / 2; k++) {uBytes[uIndex++] = bytes[srcIndex];srcIndex += pixelsStride;}if (pixelsStride == 2) {srcIndex += rowStride - width;} else if (pixelsStride == 1) {srcIndex += rowStride - width / 2;}}} else if (i == 2) {//根据pixelsStride取相应的数据for (int j = 0; j < height / 2; j++) {for (int k = 0; k < width / 2; k++) {vBytes[vIndex++] = bytes[srcIndex];srcIndex += pixelsStride;}if (pixelsStride == 2) {srcIndex += rowStride - width;} else if (pixelsStride == 1) {srcIndex += rowStride - width / 2;}}}}image.close();//根据要求的结果类型进行填充switch (type) {case YV12:System.arraycopy(uBytes, 0, yuvBytes, dstIndex, uBytes.length);System.arraycopy(vBytes, 0, yuvBytes, dstIndex + uBytes.length, vBytes.length);break;case YUV420SP:for (int i = 0; i < vBytes.length; i++) {yuvBytes[dstIndex++] = uBytes[i];yuvBytes[dstIndex++] = vBytes[i];}break;case NV21:for (int i = 0; i < vBytes.length; i++) {yuvBytes[dstIndex++] = vBytes[i];yuvBytes[dstIndex++] = uBytes[i];}break;}return yuvBytes;} catch (final Exception e) {if (image != null) {image.close();}}return null;}

4.0自定义Camera2TextureView

public class Camera2TextureView extends TextureView {private static final String TAG = "CameraTextureView";private Camera2Proxy mCameraProxy;private Context mContext;public Camera2TextureView(Context context) {this(context, null);}public Camera2TextureView(Context context, AttributeSet attrs) {this(context, attrs, 0);}public Camera2TextureView(Context context, AttributeSet attrs, int defStyleAttr) {this(context, attrs, defStyleAttr, 0);}public Camera2TextureView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) {super(context, attrs, defStyleAttr, defStyleRes);init(context);}private void init(Context context) {this.mContext = context;setSurfaceTextureListener(mSurfaceTextureListener);mCameraProxy = new Camera2Proxy((Activity) context);}private SurfaceTextureListener mSurfaceTextureListener = new SurfaceTextureListener() {@Overridepublic void onSurfaceTextureAvailable(SurfaceTexture surface, int width, int height) {Log.v(TAG, "onSurfaceTextureAvailable. width: " + width + ", height: " + height);mCameraProxy.setPreviewSurface(surface);mCameraProxy.openCamera(MediaInfo.PRIVIEW_WIDTH, MediaInfo.PRIVIEW_HEIGHT);configureTransform(width, height);// resize TextureViewint previewWidth = mCameraProxy.getPreviewSize().getWidth();int previewHeight = mCameraProxy.getPreviewSize().getHeight();if (width > height) {setAspectRatio(previewWidth, previewHeight);} else {setAspectRatio(previewHeight, previewWidth);}}@Overridepublic void onSurfaceTextureSizeChanged(SurfaceTexture surface, int width, int height) {Log.v(TAG, "onSurfaceTextureSizeChanged. width: " + width + ", height: " + height);}@Overridepublic boolean onSurfaceTextureDestroyed(SurfaceTexture surface) {Log.v(TAG, "onSurfaceTextureDestroyed");mCameraProxy.releaseCamera();return false;}@Overridepublic void onSurfaceTextureUpdated(SurfaceTexture surface) {}};private void setAspectRatio(int width, int height) {if (width < 0 || height < 0) {throw new IllegalArgumentException("Size cannot be negative.");}requestLayout();}public Camera2Proxy getCameraProxy() {return mCameraProxy;}/*** 全屏翻转* @param viewWidth* @param viewHeight*/private void configureTransform(int viewWidth, int viewHeight) {if (null == mCameraProxy.getPreviewSize() || null == mContext) {return;}int rotation = ((Activity)mContext).getWindowManager().getDefaultDisplay().getRotation();Point point = new Point();((Activity) mContext).getWindowManager().getDefaultDisplay().getSize(point);Matrix matrix = new Matrix();RectF viewRect = new RectF(0, 0, viewWidth, viewHeight);RectF bufferRect = new RectF(0, 0, point.y, point.x);float centerX = viewRect.centerX();float centerY = viewRect.centerY();if (Surface.ROTATION_90 == rotation || Surface.ROTATION_270 == rotation) {bufferRect.offset(centerX - bufferRect.centerX(), centerY - bufferRect.centerY());matrix.setRectToRect(viewRect, bufferRect, Matrix.ScaleToFit.FILL);float scale1 = Math.max((float) viewHeight /point.y,(float) viewWidth / point.x);float scale2 = Math.min((float) point.y / viewHeight,(float) point.x / viewWidth);matrix.postScale(scale1, scale2, centerX, centerY);matrix.postRotate(270 * rotation, centerX, centerY);}setTransform(matrix);}
}

5.0问题

当只进行实时画面的预览的时候，画面流畅，但加了回调算法处理后，画面会出现卡顿，帧率降低。性能差的手机帧率只有8帧左右，这是远远达不到算法检测要求的，性能好点的手机能达到60帧（两个手机都是华为的，一个是办电信网送的，一个是荣耀10），对手机性能要求较高。

四、效果

竖屏（不检测）效果：

横屏检测效果：

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