CameraX ImageCapture Hit timeout for jpeg 回调

Question

我正在尝试按照https://developer.android.com/training/camerax/take-photo 实现图像捕获，我在 Temi Robot 上运行我的设备，预览似乎工作正常，但我遇到了这个错误，当我尝试执行回调时没有执行捕捉图像。

Error

这是调用camerax代码的片段

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    viewModel = new ViewModelProvider(getActivity()).get(GlobalViewModel.class);
    cameraProviderFuture = ProcessCameraProvider.getInstance(getContext());
}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    // Inflate the layout for this fragment
    return inflater.inflate(R.layout.patrol_fragment, container, false);
}

    @Override
public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
    super.onViewCreated(view, savedInstanceState);
    previewView = view.findViewById(R.id.previewView);
    cameraProviderFuture.addListener(() -> {
        try {
            ProcessCameraProvider cameraProvider = cameraProviderFuture.get();
            bindPreview(cameraProvider, view);
        } catch (ExecutionException | InterruptedException e) {
            Log.e(TAG, "CameraProvider initialization error: " + e.toString());
        }
    }, ContextCompat.getMainExecutor(getContext()));
         Just for testing
        Handler handler = new Handler();
        handler.postDelayed(new Runnable() {
            @Override
            public void run() {
                takePicture();
            }
        }, 10000);
}

private void bindPreview(ProcessCameraProvider cameraProvider, View view) {
    Preview preview = new Preview.Builder().build();
    CameraSelector cameraSelector = new CameraSelector.Builder()
            .requireLensFacing(CameraSelector.LENS_FACING_FRONT)
            .build();

    preview.setSurfaceProvider(previewView.getSurfaceProvider());

    imageCapture = new ImageCapture.Builder()
            .setTargetRotation(view.getDisplay().getRotation())
            .setCaptureMode(ImageCapture.CAPTURE_MODE_MINIMIZE_LATENCY)
            .build();

    Camera camera = cameraProvider.bindToLifecycle(getActivity(), cameraSelector, imageCapture,
            preview);

    takePicture();

}

private void takePicture() {
    File mediaFile = getMediaFile();

    ImageCapture.OutputFileOptions outputFileOptions =
            new ImageCapture.OutputFileOptions.Builder(mediaFile).build();
    imageCapture.takePicture(outputFileOptions, viewModel.getExecutorService(),
            new ImageCapture.OnImageSavedCallback() {
                @Override
                public void onImageSaved(ImageCapture.OutputFileResults outputFileResults) {
                    // insert your code here.
                    Log.i(TAG, "Capture success!");
                }

                @Override
                public void onError(ImageCaptureException error) {
                    // insert your code here.
                    Log.e(TAG, "Capture failed :( " + error.toString());

                }
            }
    );
}

private File getMediaFile() {
    File mediaStorageDir = new File(Environment.getExternalStoragePublicDirectory(
            Environment.DIRECTORY_PICTURES), "TemiPatrol");
    if (! mediaStorageDir.exists()){
        if (! mediaStorageDir.mkdirs()){
            Log.d(TAG, "failed to create directory");
            return null;
        }
    }
    String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
    return new File(mediaStorageDir.getPath() + File.separator +
            "IMG_"+ timeStamp + ".jpg");
}

private void sendImageToServer(JSONObject requestJson) {
    // for testing
    viewModel.getExecutorService().execute(() -> {
        JsonPostman postman = new JsonPostman(getActivity());
        postman.postRequest(requestJson);
    });
}

}

Answer 1

您无法拍照，因为ImageCapture 设置不正确，您在调用ProcessCameraProvider.bindToLifecycle() 时未绑定它。你应该这样写：

Preview preview = ...;
preview.setSurfaceProvider(...);

ImageCapture imageCapture = ...;

// bind both preview and imageCapture
cameraProvider.bindToLifecycle(lifecycleOwner, cameraSelector, preview, imageCapture);

这将（应该）允许对takePicture() 的调用成功。

我还有另外 2 个关于你的代码的 cmets。

1. 您为测试目的添加的代码（您安排在 10 秒后拍摄图像）应仅在相机设置有效的情况下执行。例如，您可以在调用 bindToLifecycle() 之后运行它。

2. 将用例绑定到片段 Activity 的生命周期可能不是一个好主意。 bindToLifecycle(LifecycleOwner, ...) 中的生命周期所有者控制相机何时打开和关闭，因此您通常希望在片段或其视图启动时启动相机，并在片段或其视图停止时停止相机。由于您正在显示预览，因此您可以将相机的打开/关闭与片段视图的生命周期联系起来，因此您可以编写：

cameraProvider.bindToLifecycle(getViewLifecycleOwner(), cameraSelector, preview, imageCapture);