Java tutorial
/** * Based on https://developer.android.com/samples/Camera2Basic/src/com.example.android.camera2basic/Camera2BasicFragment.html */ package com.microblink.barcode.customcamera.camera2; import android.Manifest; import android.annotation.TargetApi; import android.app.Activity; import android.app.AlertDialog; import android.app.Dialog; import android.app.DialogFragment; import android.app.Fragment; import android.content.Context; import android.content.DialogInterface; import android.content.Intent; import android.content.pm.PackageManager; import android.content.res.Configuration; import android.graphics.ImageFormat; import android.graphics.Matrix; import android.graphics.Point; import android.graphics.RectF; import android.graphics.SurfaceTexture; import android.hardware.camera2.CameraAccessException; import android.hardware.camera2.CameraCaptureSession; import android.hardware.camera2.CameraCharacteristics; import android.hardware.camera2.CameraDevice; import android.hardware.camera2.CameraManager; import android.hardware.camera2.CaptureRequest; import android.hardware.camera2.params.StreamConfigurationMap; import android.media.Image; import android.media.ImageReader; import android.os.Bundle; import android.os.Handler; import android.os.HandlerThread; import android.support.annotation.NonNull; import android.support.v4.content.ContextCompat; import android.util.Log; import android.util.Size; import android.view.LayoutInflater; import android.view.Surface; import android.view.TextureView; import android.view.View; import android.view.ViewGroup; import android.widget.Toast; import com.microblink.activity.BaseScanActivity; import com.microblink.barcode.R; import com.microblink.directApi.DirectApiErrorListener; import com.microblink.directApi.Recognizer; import com.microblink.hardware.orientation.Orientation; import com.microblink.image.ImageBuilder; import com.microblink.recognition.FeatureNotSupportedException; import com.microblink.recognition.InvalidLicenceKeyException; import com.microblink.recognizers.BaseRecognitionResult; import com.microblink.recognizers.RecognitionResults; import com.microblink.recognizers.settings.RecognitionSettings; import com.microblink.view.recognition.ScanResultListener; import java.util.ArrayList; import java.util.Arrays; import java.util.Collections; import java.util.Comparator; import java.util.List; import java.util.concurrent.Semaphore; import java.util.concurrent.TimeUnit; /** * Created by dodo on 11/02/16. */ @TargetApi(21) public class Camera2Fragment extends Fragment implements ScanResultListener { private static final String FRAGMENT_DIALOG = "dialog"; /** * Tag for the {@link Log}. */ private static final String TAG = "Camera2Fragment"; /** * Max preview width that is guaranteed by Camera2 API */ private static final int MAX_PREVIEW_WIDTH = 1920; /** * Max preview height that is guaranteed by Camera2 API */ private static final int MAX_PREVIEW_HEIGHT = 1080; private Recognizer mRecognizer; private RecognitionSettings mSettings = new RecognitionSettings(); private String mLicenseKey = null; private Image mImageBeingRecognized = null; private long mTimestamp; /** * This a callback object for the {@link ImageReader}. "onImageAvailable" will be called when a * still image is ready to be saved. */ private final ImageReader.OnImageAvailableListener mOnImageAvailableListener = new ImageReader.OnImageAvailableListener() { @Override public void onImageAvailable(ImageReader reader) { Image img = null; try { img = reader.acquireNextImage(); if (img != null) { if (mRecognizer.getCurrentState() == Recognizer.State.READY) { mImageBeingRecognized = img; com.microblink.image.Image image = ImageBuilder.buildImageFromCamera2Image( mImageBeingRecognized, Orientation.ORIENTATION_LANDSCAPE_RIGHT, null); Log.i(TAG, "Starting recognition"); mTimestamp = System.currentTimeMillis(); mRecognizer.recognizeImage(image, Camera2Fragment.this); } else { Log.v(TAG, "Recognizer is busy. Dropping current frame"); img.close(); // request another frame mCaptureSession.capture(mFrameRequest, null, mBackgroundHandler); } } } catch (Exception e) { if (img != null) { img.close(); } try { // request frame to image reader mCaptureSession.capture(mFrameRequest, null, mBackgroundHandler); } catch (Exception exc) { Log.w(TAG, "Failed to capture another frame for ImageReader"); } } } }; /** * ID of the current {@link CameraDevice}. */ private String mCameraId; /** * An {@link AutoFitTextureView} for camera preview. */ private AutoFitTextureView mTextureView; /** * A {@link CameraCaptureSession } for camera preview. */ private CameraCaptureSession mCaptureSession; /** * A reference to the opened {@link CameraDevice}. */ private CameraDevice mCameraDevice; /** * The {@link Size} of camera preview. */ private Size mPreviewSize; /** * An additional thread for running tasks that shouldn't block the UI. */ private HandlerThread mBackgroundThread; /** * A {@link Handler} for running tasks in the background. */ private Handler mBackgroundHandler; /** * An {@link ImageReader} that handles still image capture. */ private ImageReader mImageReader; /** * {@link CaptureRequest.Builder} for the camera preview */ private CaptureRequest.Builder mPreviewRequestBuilder; /** * {@link CaptureRequest} generated by {@link #mPreviewRequestBuilder} */ private CaptureRequest mPreviewRequest; /** * Capture request for getting frame to ImageReader. */ private CaptureRequest mFrameRequest; /** * A {@link Semaphore} to prevent the app from exiting before closing the camera. */ private Semaphore mCameraOpenCloseLock = new Semaphore(1); /** * {@link CameraDevice.StateCallback} is called when {@link CameraDevice} changes its state. */ private final CameraDevice.StateCallback mStateCallback = new CameraDevice.StateCallback() { @Override public void onOpened(@NonNull CameraDevice cameraDevice) { // This method is called when the camera is opened. We start camera preview here. mCameraOpenCloseLock.release(); mCameraDevice = cameraDevice; createCameraPreviewSession(); } @Override public void onDisconnected(@NonNull CameraDevice cameraDevice) { mCameraOpenCloseLock.release(); cameraDevice.close(); mCameraDevice = null; } @Override public void onError(@NonNull CameraDevice cameraDevice, int error) { mCameraOpenCloseLock.release(); cameraDevice.close(); mCameraDevice = null; Activity activity = getActivity(); if (null != activity) { activity.finish(); } } }; /** * {@link TextureView.SurfaceTextureListener} handles several lifecycle events on a * {@link TextureView}. */ private final TextureView.SurfaceTextureListener mSurfaceTextureListener = new TextureView.SurfaceTextureListener() { @Override public void onSurfaceTextureAvailable(SurfaceTexture texture, int width, int height) { openCamera(width, height); } @Override public void onSurfaceTextureSizeChanged(SurfaceTexture texture, int width, int height) { configureTransform(width, height); } @Override public boolean onSurfaceTextureDestroyed(SurfaceTexture texture) { return true; } @Override public void onSurfaceTextureUpdated(SurfaceTexture texture) { } }; /** * Given {@code choices} of {@code Size}s supported by a camera, choose the smallest one that * is at least as large as the respective texture view size, and that is at most as large as the * respective max size, and whose aspect ratio matches with the specified value. If such size * doesn't exist, choose the largest one that is at most as large as the respective max size, * and whose aspect ratio matches with the specified value. * * @param choices The list of sizes that the camera supports for the intended output * class * @param maxWidth The maximum width that can be chosen * @param maxHeight The maximum height that can be chosen * @param aspectRatio The aspect ratio * @return The optimal {@code Size}, or an arbitrary one if none were big enough */ private static Size chooseOptimalSize(Size[] choices, int maxWidth, int maxHeight, Size aspectRatio) { // Collect the supported resolutions that are at least as big as the preview Surface List<Size> bigEnough = new ArrayList<>(); int w = aspectRatio.getWidth(); int h = aspectRatio.getHeight(); for (Size option : choices) { if (option.getWidth() <= maxWidth && option.getHeight() <= maxHeight && option.getHeight() == option.getWidth() * h / w) { bigEnough.add(option); } } // Pick the largest of those big enough. if (bigEnough.size() > 0) { return Collections.max(bigEnough, new CompareSizesByArea()); } else { Log.e(TAG, "Couldn't find any suitable preview size"); return choices[0]; } } public static Camera2Fragment newInstance() { return new Camera2Fragment(); } @Override public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) { return inflater.inflate(R.layout.fragment_camera2, container, false); } @Override public void onViewCreated(final View view, Bundle savedInstanceState) { mTextureView = (AutoFitTextureView) view.findViewById(R.id.texture); } @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); Intent intent = getActivity().getIntent(); Bundle extras = intent.getExtras(); if (extras != null) { mSettings = extras.getParcelable(BaseScanActivity.EXTRAS_RECOGNITION_SETTINGS); mLicenseKey = extras.getString(BaseScanActivity.EXTRAS_LICENSE_KEY); } } @Override public void onStart() { super.onStart(); try { mRecognizer = Recognizer.getSingletonInstance(); } catch (FeatureNotSupportedException e) { Toast.makeText(Camera2Fragment.this.getActivity(), "Feature not supported! Reason: " + e.getReason().getDescription(), Toast.LENGTH_LONG).show(); getActivity().finish(); return; } try { // In order for scanning to work, you must enter a valid licence key. Without licence key, // scanning will not work. Licence key is bound the the package name of your app, so when // obtaining your licence key from Microblink make sure you give us the correct package name // of your app. You can obtain your licence key at http://microblink.com/login or contact us // at http://help.microblink.com. // Licence key also defines which recognizers are enabled and which are not. Since the licence // key validation is performed on image processing thread in native code, all enabled recognizers // that are disallowed by licence key will be turned off without any error and information // about turning them off will be logged to ADB logcat. mRecognizer.setLicenseKey(Camera2Fragment.this.getActivity(), mLicenseKey); } catch (InvalidLicenceKeyException exc) { Toast.makeText(Camera2Fragment.this.getActivity(), "License key check failed! Reason: " + exc.getMessage(), Toast.LENGTH_LONG).show(); getActivity().finish(); return; } mRecognizer.initialize(getActivity(), mSettings, new DirectApiErrorListener() { @Override public void onRecognizerError(Throwable t) { Toast.makeText(Camera2Fragment.this.getActivity(), "There was an error in Recognizer: " + t.getMessage(), Toast.LENGTH_SHORT).show(); getActivity().finish(); } }); } @Override public void onResume() { super.onResume(); startBackgroundThread(); // When the screen is turned off and turned back on, the SurfaceTexture is already // available, and "onSurfaceTextureAvailable" will not be called. In that case, we can open // a camera and start preview from here (otherwise, we wait until the surface is ready in // the SurfaceTextureListener). if (mTextureView.isAvailable()) { openCamera(mTextureView.getWidth(), mTextureView.getHeight()); } else { mTextureView.setSurfaceTextureListener(mSurfaceTextureListener); } } @Override public void onPause() { closeCamera(); stopBackgroundThread(); super.onPause(); } @Override public void onStop() { super.onStop(); if (mRecognizer != null) { mRecognizer.terminate(); } } /** * Sets up member variables related to camera. * * @param width The width of available size for camera preview * @param height The height of available size for camera preview */ private void setUpCameraOutputs(int width, int height) { Activity activity = getActivity(); CameraManager manager = (CameraManager) activity.getSystemService(Context.CAMERA_SERVICE); try { for (String cameraId : manager.getCameraIdList()) { CameraCharacteristics characteristics = manager.getCameraCharacteristics(cameraId); // We don't use a front facing camera in this sample. Integer facing = characteristics.get(CameraCharacteristics.LENS_FACING); if (facing != null && facing == CameraCharacteristics.LENS_FACING_FRONT) { continue; } StreamConfigurationMap map = characteristics .get(CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP); if (map == null) { continue; } // For still image captures, we use the largest available size. Size largest = Collections.max(Arrays.asList(map.getOutputSizes(ImageFormat.YUV_420_888)), new CompareSizesByArea()); // Find out if we need to swap dimension to get the preview size relative to sensor // coordinate. int displayRotation = activity.getWindowManager().getDefaultDisplay().getRotation(); int sensorOrientation = characteristics.get(CameraCharacteristics.SENSOR_ORIENTATION); boolean swappedDimensions = false; switch (displayRotation) { case Surface.ROTATION_0: case Surface.ROTATION_180: if (sensorOrientation == 90 || sensorOrientation == 270) { swappedDimensions = true; } break; case Surface.ROTATION_90: case Surface.ROTATION_270: if (sensorOrientation == 0 || sensorOrientation == 180) { swappedDimensions = true; } break; default: Log.e(TAG, "Display rotation is invalid: " + displayRotation); } Point displaySize = new Point(); activity.getWindowManager().getDefaultDisplay().getSize(displaySize); int maxPreviewWidth = displaySize.x; int maxPreviewHeight = displaySize.y; if (swappedDimensions) { maxPreviewWidth = displaySize.y; maxPreviewHeight = displaySize.x; } if (maxPreviewWidth > MAX_PREVIEW_WIDTH) { maxPreviewWidth = MAX_PREVIEW_WIDTH; } if (maxPreviewHeight > MAX_PREVIEW_HEIGHT) { maxPreviewHeight = MAX_PREVIEW_HEIGHT; } // Danger, W.R.! Attempting to use too large a preview size could exceed the camera // bus' bandwidth limitation, resulting in gorgeous previews but the storage of // garbage capture data. mPreviewSize = chooseOptimalSize(map.getOutputSizes(SurfaceTexture.class), maxPreviewWidth, maxPreviewHeight, largest); Log.i(TAG, "Preview size is " + mPreviewSize.toString()); mImageReader = ImageReader.newInstance(mPreviewSize.getWidth(), mPreviewSize.getHeight(), ImageFormat.YUV_420_888, /*maxImages*/1); mImageReader.setOnImageAvailableListener(mOnImageAvailableListener, mBackgroundHandler); // We fit the aspect ratio of TextureView to the size of preview we picked. int orientation = getResources().getConfiguration().orientation; if (orientation == Configuration.ORIENTATION_LANDSCAPE) { mTextureView.setAspectRatio(mPreviewSize.getWidth(), mPreviewSize.getHeight()); } else { mTextureView.setAspectRatio(mPreviewSize.getHeight(), mPreviewSize.getWidth()); } mCameraId = cameraId; return; } } catch (CameraAccessException e) { e.printStackTrace(); } catch (NullPointerException e) { // Currently an NPE is thrown when the Camera2API is used but not supported on the // device this code runs. ErrorDialog.newInstance("Camera error").show(getChildFragmentManager(), FRAGMENT_DIALOG); } } /** * Opens the camera specified by {@link Camera2Fragment#mCameraId}. */ private void openCamera(int width, int height) { if (ContextCompat.checkSelfPermission(getActivity(), Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) { getActivity().finish(); return; } setUpCameraOutputs(width, height); configureTransform(width, height); Activity activity = getActivity(); CameraManager manager = (CameraManager) activity.getSystemService(Context.CAMERA_SERVICE); try { if (!mCameraOpenCloseLock.tryAcquire(2500, TimeUnit.MILLISECONDS)) { throw new RuntimeException("Time out waiting to lock camera opening."); } manager.openCamera(mCameraId, mStateCallback, mBackgroundHandler); } catch (CameraAccessException e) { e.printStackTrace(); } catch (InterruptedException e) { throw new RuntimeException("Interrupted while trying to lock camera opening.", e); } } /** * Closes the current {@link CameraDevice}. */ private void closeCamera() { try { mCameraOpenCloseLock.acquire(); if (null != mCaptureSession) { mCaptureSession.close(); mCaptureSession = null; } if (null != mCameraDevice) { mCameraDevice.close(); mCameraDevice = null; } if (null != mImageReader) { mImageReader.close(); mImageReader = null; } } catch (InterruptedException e) { throw new RuntimeException("Interrupted while trying to lock camera closing.", e); } finally { mCameraOpenCloseLock.release(); } } /** * Starts a background thread and its {@link Handler}. */ private void startBackgroundThread() { mBackgroundThread = new HandlerThread("CameraBackground"); mBackgroundThread.start(); mBackgroundHandler = new Handler(mBackgroundThread.getLooper()); } /** * Stops the background thread and its {@link Handler}. */ private void stopBackgroundThread() { mBackgroundThread.quitSafely(); try { mBackgroundThread.join(); mBackgroundThread = null; mBackgroundHandler = null; } catch (InterruptedException e) { e.printStackTrace(); } } /** * Creates a new {@link CameraCaptureSession} for camera preview. */ private void createCameraPreviewSession() { try { SurfaceTexture texture = mTextureView.getSurfaceTexture(); assert texture != null; // We configure the size of default buffer to be the size of camera preview we want. texture.setDefaultBufferSize(mPreviewSize.getWidth(), mPreviewSize.getHeight()); // This is the output Surface we need to start preview. Surface surface = new Surface(texture); // We set up a CaptureRequest.Builder with the output Surface. mPreviewRequestBuilder = mCameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW); mPreviewRequestBuilder.addTarget(surface); // Here, we create a CameraCaptureSession for camera preview. mCameraDevice.createCaptureSession(Arrays.asList(surface, mImageReader.getSurface()), new CameraCaptureSession.StateCallback() { @Override public void onConfigured(@NonNull CameraCaptureSession cameraCaptureSession) { // The camera is already closed if (null == mCameraDevice) { return; } // When the session is ready, we start displaying the preview. mCaptureSession = cameraCaptureSession; try { // Auto focus should be continuous for camera preview. mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AF_MODE, CaptureRequest.CONTROL_AF_MODE_CONTINUOUS_PICTURE); mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AE_MODE, CaptureRequest.CONTROL_AE_MODE_ON); // Finally, we start displaying the camera preview. mPreviewRequest = mPreviewRequestBuilder.build(); mCaptureSession.setRepeatingRequest(mPreviewRequest, null, mBackgroundHandler); // also prepare capture request for ImageReader mPreviewRequestBuilder.addTarget(mImageReader.getSurface()); mFrameRequest = mPreviewRequestBuilder.build(); mPreviewRequestBuilder.removeTarget(mImageReader.getSurface()); // request frame to image reader mCaptureSession.capture(mFrameRequest, null, mBackgroundHandler); } catch (CameraAccessException e) { e.printStackTrace(); } } @Override public void onConfigureFailed(@NonNull CameraCaptureSession cameraCaptureSession) { showToast("Failed"); } }, null); } catch (CameraAccessException e) { e.printStackTrace(); } } /** * Shows a {@link Toast} on the UI thread. * * @param text The message to show */ private void showToast(final String text) { final Activity activity = getActivity(); if (activity != null) { activity.runOnUiThread(new Runnable() { @Override public void run() { Toast.makeText(activity, text, Toast.LENGTH_SHORT).show(); } }); } } /** * Configures the necessary {@link Matrix} transformation to `mTextureView`. * This method should be called after the camera preview size is determined in * setUpCameraOutputs and also the size of `mTextureView` is fixed. * * @param viewWidth The width of `mTextureView` * @param viewHeight The height of `mTextureView` */ private void configureTransform(int viewWidth, int viewHeight) { Activity activity = getActivity(); if (null == mTextureView || null == mPreviewSize || null == activity) { return; } int rotation = activity.getWindowManager().getDefaultDisplay().getRotation(); Matrix matrix = new Matrix(); RectF viewRect = new RectF(0, 0, viewWidth, viewHeight); RectF bufferRect = new RectF(0, 0, mPreviewSize.getHeight(), mPreviewSize.getWidth()); 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 scale = Math.max((float) viewHeight / mPreviewSize.getHeight(), (float) viewWidth / mPreviewSize.getWidth()); matrix.postScale(scale, scale, centerX, centerY); matrix.postRotate(90 * (rotation - 2), centerX, centerY); } else if (Surface.ROTATION_180 == rotation) { matrix.postRotate(180, centerX, centerY); } mTextureView.setTransform(matrix); } @Override public void onScanningDone(RecognitionResults results) { long timePassed = System.currentTimeMillis() - mTimestamp; Log.w(TAG, "Frame processing took " + timePassed + " ms"); // check if results contain valid data BaseRecognitionResult[] brrs = results.getRecognitionResults(); boolean haveSomething = false; if (brrs != null) { for (BaseRecognitionResult brr : brrs) { if (!brr.isEmpty()) { haveSomething = true; break; } } } mImageBeingRecognized.close(); if (haveSomething) { // return results Intent intent = new Intent(); intent.putExtra(BaseScanActivity.EXTRAS_RECOGNITION_RESULTS, results); getActivity().setResult(BaseScanActivity.RESULT_OK, intent); getActivity().finish(); } else { try { // request frame to image reader mCaptureSession.capture(mFrameRequest, null, mBackgroundHandler); } catch (Exception exc) { Log.w(TAG, "Failed to capture another frame for ImageReader"); } } } /** * Compares two {@code Size}s based on their areas. */ static class CompareSizesByArea implements Comparator<Size> { @Override public int compare(Size lhs, Size rhs) { // We cast here to ensure the multiplications won't overflow return Long.signum((long) lhs.getWidth() * lhs.getHeight() - (long) rhs.getWidth() * rhs.getHeight()); } } /** * Shows an error message dialog. */ public static class ErrorDialog extends DialogFragment { private static final String ARG_MESSAGE = "message"; public static ErrorDialog newInstance(String message) { ErrorDialog dialog = new ErrorDialog(); Bundle args = new Bundle(); args.putString(ARG_MESSAGE, message); dialog.setArguments(args); return dialog; } @Override public Dialog onCreateDialog(Bundle savedInstanceState) { final Activity activity = getActivity(); return new AlertDialog.Builder(activity).setMessage(getArguments().getString(ARG_MESSAGE)) .setPositiveButton(android.R.string.ok, new DialogInterface.OnClickListener() { @Override public void onClick(DialogInterface dialogInterface, int i) { activity.finish(); } }).create(); } } }