How to enable front camera in Camera2 API?

Question

How to enable front camera on Camera2 API.Can anyone help ? I have this Camera2 API code .This only sets Main camera of the device ,I want to enable both front and rear camera on a button click.What is LENS_FACING_FRONT,I am new to android programming.

 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.JPEG)),
                    new CompareSizesByArea());
            mImageReader = ImageReader.newInstance(largest.getWidth(), largest.getHeight(),
                    ImageFormat.JPEG, /*maxImages*/2);
            mImageReader.setOnImageAvailableListener(
                    mOnImageAvailableListener, mBackgroundHandler);

            // 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),
                    width, height, largest);

            // 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(getString(R.string.camera_error))
                .show(getChildFragmentManager(), FRAGMENT_DIALOG);
    }
}

Answer 1

We can use CameraManager to iterate all the cameras that are available in the system, each with a designated cameraId. Using the cameraId, we can get the properties of the specified camera device. Those properties are represented by class CameraCharacteristics. Things like "is it front or back camera", "output resolutions supported" can be queried there.

You can get official sample application here

This example found in Google Git repo will demo for you checking the permission before launching camera in new Marshmallow using Camera2 API

Give a look at this article for more about it.