Android CAMERA 2 API捕获0kb图像并提供全白预览。 在logcat上不显示任何错误或警告

Question

我将Android CAMERA 2 API用于支持我的应用程序中的camera2支持的手机。 效果很好，但有时会捕获0kb图像并提供全白预览 。 在logcat上不显示任何错误或警告。 以下是我的相机图像捕获和保存代码：

protected void takePictureViaCamera2() {
    if (null == cameraDevice) {
        Log.e(TAG, "cameraDevice is null");
        return;
    }
    CameraManager manager = (CameraManager) getSystemService(Context.CAMERA_SERVICE);
    try {
        CameraCharacteristics characteristics = manager.getCameraCharacteristics(cameraDevice.getId());
        Size[] jpegSizes = null;
        if (characteristics != null) {
            jpegSizes = characteristics.get(CameraCharacteristics.SCALER_STREAM_CONFIGURATION_MAP).getOutputSizes(ImageFormat.JPEG);
        }
        int width = 640;
        int height = 480;
        if (jpegSizes != null && 0 < jpegSizes.length) {
            width = jpegSizes[0].getWidth();
            height = jpegSizes[0].getHeight();
        }
        ImageReader reader = ImageReader.newInstance(width, height, ImageFormat.JPEG, 1);
        List<Surface> outputSurfaces = new ArrayList<Surface>(2);
        outputSurfaces.add(reader.getSurface());
        outputSurfaces.add(new Surface(textureView.getSurfaceTexture()));
        final CaptureRequest.Builder captureBuilder = cameraDevice.createCaptureRequest(CameraDevice.TEMPLATE_STILL_CAPTURE);
        captureBuilder.addTarget(reader.getSurface());
        captureBuilder.set(CaptureRequest.CONTROL_MODE, CameraMetadata.CONTROL_MODE_AUTO);
        // Orientation
        int rotation = getWindowManager().getDefaultDisplay().getRotation();
        captureBuilder.set(CaptureRequest.JPEG_ORIENTATION, ORIENTATIONS.get(rotation));
        //final File file = new File(Environment.getExternalStorageDirectory()+"/pic.jpg");
        final File file = createImageFile();
        final String checkPath = file.getParent();
        Log.e("checkPath", checkPath);
        //photoFile = createImageFile();
        //photoFilePath  = photoFile.getParent();
        //Log.e("photoFilePath", photoFilePath);
        ImageReader.OnImageAvailableListener readerListener = new ImageReader.OnImageAvailableListener() {
            @Override
            public void onImageAvailable(ImageReader reader) {
                Image image = null;
                try {
                    image = reader.acquireLatestImage();
                    ByteBuffer buffer = image.getPlanes()[0].getBuffer();
                    byte[] bytes = new byte[buffer.capacity()];
                    buffer.get(bytes);
                    save(bytes);
                } catch (FileNotFoundException e) {
                    e.printStackTrace();
                    Log.e("readerListenerFNF_EX", e + "");
                } catch (IOException e) {
                    e.printStackTrace();
                    Log.e("readerListenerIO_EX", e + "");
                } catch (Exception e) {
                    e.printStackTrace();
                    Log.e("readerListener_EX", e + "");
                } finally {
                    if (image != null) {
                        image.close();
                    }
                }
            }

            private void save(byte[] bytes) throws IOException {
                OutputStream output = null;
                try {
                    output = new FileOutputStream(file);
                    //output = new FileOutputStream(photoFile);
                    output.write(bytes);
                } finally {
                    if (null != output) {
                        output.close();
                    }
                }
            }
        };
        reader.setOnImageAvailableListener(readerListener, mBackgroundHandler);
        final CameraCaptureSession.CaptureCallback captureListener = new CameraCaptureSession.CaptureCallback() {
            @Override
            public void onCaptureCompleted(CameraCaptureSession session, CaptureRequest request, TotalCaptureResult result) {
                super.onCaptureCompleted(session, request, result);
                Toast.makeText(TravelChargesCamera2Activity.this, "Saved***:" + file, Toast.LENGTH_SHORT).show();
                createCameraPreview();
                closeCamera();


                Thread thread = new Thread() {
                    @Override
                    public void run() {
                        try {
                            synchronized (this) {
                                wait(5000);

                                runOnUiThread(new Runnable() {
                                    @Override
                                    public void run() {
                                        toolbar.setVisibility(View.VISIBLE);
                                        header.setVisibility(View.VISIBLE);
                                        assessorTraveldetails_scroll.setVisibility(View.VISIBLE);
                                        camera2Layout.setVisibility(View.GONE);

                                        try {

                                            if (!file.getParentFile().isDirectory()) {

                                                travelDirectory = new File(checkPath);
                                                Log.e("travelDir==created==", travelDirectory + "");
                                            } else {

                                                travelDirectory = file.getParentFile();
                                                Log.e("travelDir==exists==", travelDirectory + "");
                                            }

                                            files = travelDirectory.listFiles();
                                            Log.e("files", files + "");

                                            // removes old images from view
                                            // prevents  display duplication
                                            travelGallery.removeAllViews();

                                            // loop displays the photos captured on Horizontal ScrollView
                                            for (File picFile : files) {
                                                travelGallery.addView(insertPhoto(picFile.getAbsolutePath()));

                                                byte[] byteArray = ImageUtils.fileToByteArray(file);
                                                Log.e("byteArray", byteArray + "");
                                            }

                                        } catch (Exception e) {
                                            e.printStackTrace();
                                            Log.e("file", e + "");
                                        }
                                    }
                                });

                            }
                        } catch (InterruptedException e) {
                            e.printStackTrace();
                            Log.e("InterruptedException", e + "");
                        } catch (Exception e) {
                            e.printStackTrace();
                            Log.e("Exception", e + "");
                        }
                    }
                };
                thread.start();

            }
        };
        cameraDevice.createCaptureSession(outputSurfaces, new CameraCaptureSession.StateCallback() {
            @Override
            public void onConfigured(CameraCaptureSession session) {
                try {
                    session.capture(captureBuilder.build(), captureListener, mBackgroundHandler);
                } catch (CameraAccessException e) {
                    e.printStackTrace();
                }
            }

            @Override
            public void onConfigureFailed(CameraCaptureSession session) {
            }
        }, mBackgroundHandler);
    } catch (CameraAccessException e) {
        e.printStackTrace();
        Log.e("CameraAccessException", e + "");
    } catch (Exception e) {
        e.printStackTrace();
        Log.e("takePictureViaCamera2", e + "");
    }
}

private File createImageFile() throws IOException {
    // Create an image file name

    String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
    String uniqueId = UUID.randomUUID().toString();
    String imageFileName = "CAP_" + timeStamp + "_" + uniqueId;


    String bCode = "";

    masterMap = (LinkedTreeMap) gson.fromJson(batchMasterObject.getMasterJson(), Object.class);
    auditMap = (LinkedTreeMap) masterMap.get("2001");
    if ((auditMap.get("batchCode") != null && !auditMap.get("batchCode").equals(""))) {
        bCode = auditMap.get("batchCode").toString();
    } else if (auditMap.get("cbc") != null && !auditMap.get("cbc").equals("")) {
        bCode = auditMap.get("cbc").toString();
    }


    File storageDir = new File(getExternalFilesDir(Environment.DIRECTORY_PICTURES), "/" + bCode + "/Travel/");

    if (!storageDir.exists()) {
        storageDir.mkdirs();
    }
    String checkPath = storageDir.getPath();
    Log.e("checkPath", checkPath);

    Toast.makeText(getApplicationContext(), checkPath, Toast.LENGTH_LONG).show();

    File image = File.createTempFile(
            imageFileName,  /* prefix */
            ".jpg",         /* suffix */
            storageDir      /* directory */
    );

    // Save a file: path for use with ACTION_VIEW intents        
    mCurrentPhotoPath = storageDir.getAbsolutePath();
    return image;
}

有人可以帮忙吗？

注意：相机会按预期捕获和存储图像文件，但是文件大小为0kb。 在手机或PC上打开图片文件时，显示“不支持的格式”

Answer 1

好像您将最终的JPEG捕获作为第一帧。

这意味着相机的自动曝光例程没有任何时间可用（因为您正在抓取第一帧），因此将使用硬编码到相机驱动程序中的初始设置来捕获图像。 这可能适用于某些场景，但在另一些场景中，图像将太亮或太暗。

为了获得最佳效果，您应该先让相机测光一会儿，直到自动曝光和自动对焦收敛为止。

通常，可以通过设置低分辨率预览输出（例如，使用SurfaceTexture）并运行一两秒（或等到CaptureResult的AE_STATE为CONVERGED来完成）。 然后发出JPEG捕获。