Question

我尝试使用Camera2 API将相机数据流式传输到SurfaceView。我按照本指南操作：Camera2 guide

我无法通过step 5

MainActivity.java::onCreate（）

setContentView(R.layout.activity_main);

surfaceView = (SurfaceView)findViewById(R.id.surface);
manager = (CameraManager)getSystemService(Context.CAMERA_SERVICE);

MainActivity.java::onClick（）

for (String id : manager.getCameraIdList()) {
    CameraCharacteristics characteristics = manager.getCameraCharacteristics(id);

    Integer direction = characteristics.get(CameraCharacteristics.LENS_FACING);

    if (direction != null && direction == CameraCharacteristics.LENS_FACING_BACK) {
        if (checkCallingOrSelfPermission("android.permission.CAMERA") == PackageManager.PERMISSION_GRANTED)
            manager.openCamera(id, new StateCallback(), null);

        break;
    }
}

MainActivity.java.StateCallback :: onOpened（CameraDevice camera）

List<Surface> surfaces = new LinkedList<>();
surfaces.add(surfaceView.getHolder().getSurface());

CaptureRequest.Builder builder = camera.createCaptureRequest(CameraDevice.TEMPLATE_PREVIEW);
builder.addTarget(surfaces.get(0));

camera.createCaptureSession(surfaces, new CameraCaptureSession.StateCallback() {
    @Override
    public void onConfigured(CameraCaptureSession session) {
        Log.i(TAG, "Configured");
    }

    @Override
    public void onConfigureFailed(CameraCaptureSession session) {
        Log.e(TAG, "Configured failed"); // Ends up in this function :(
    }
    }, null);

该程序最终在onConfigureFailed()函数中。我不知道可能是什么错误，我也不知道如何查看错误。

我的猜测是我错过了CaptureRequest中的某些内容，但我不知道是什么。

我正在Samsung Galaxy S4上运行。

Answer 1

像这样覆盖onConfigureFailed()：

   @Override
   public void onConfigureFailed(CameraCaptureSession session) {
       ImageReader mReader = ImageReader.newInstance(640, 480, ImageFormat.JPEG, 1);
       takePicture() // function to get image
       createCameraPreview(); // function to set camera Preview on screen
   }

调用createCameraPreview函数重新启动相机，否则它将卡住。您可以使用新值更改ImageReader

ImageReader mReader = ImageReader.newInstance(640, 480, ImageFormat.JPEG, 1);

然后再次调用takePicture()函数，以便用户不必再次单击即可捕获图像。

Answer 2

添加到onConfigured：

  if (null == cameraDevice) {
        Log.e(TAG, "updatePreview error, return");
        return;
    }
    captureRequestBuilder.set(CaptureRequest.CONTROL_MODE, CameraMetadata.CONTROL_MODE_AUTO);
    try {
        cameraCaptureSessions.setRepeatingRequest(captureRequestBuilder.build(), null, mBackgroundHandler);
    } catch (CameraAccessException e) {
        e.printStackTrace();
    }

CameraDevice无法创建会话[Camera2]

2 个答案: