Flashlight Camera2 API

Question

Can I use camera preview and flashlight at the same time in Android Camera2 API?

When I try use CameraManager.setTorchMode(String cameraId, boolean enabled) it's work fine when camera is not opened. But when Camera is open and I try setTorchMode I receive this exception:

CameraService: setTorchMode: torch mode of camera 0 is not available because camera is in use

Answer 1

Setting both FLASH_MODE and AE_MODE is important. Below is the working piece of code:

public void toggleFlashMode(boolean enable){
try {
            if (mCameraType.equals(CameraType.BACK)) {
                if (enable) {
                    mPreviewRequestBuilder.set(CaptureRequest.FLASH_MODE, CaptureRequest.FLASH_MODE_TORCH);
                    mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AE_MODE, CaptureRequest.CONTROL_AE_MODE_ON);
                } else {
                    mPreviewRequestBuilder.set(CaptureRequest.FLASH_MODE, CaptureRequest.FLASH_MODE_OFF);
                    mPreviewRequestBuilder.set(CaptureRequest.CONTROL_AE_MODE, CaptureRequest.CONTROL_AE_MODE_OFF);
                }
                mCaptureSession.setRepeatingRequest(mPreviewRequestBuilder.build(), null, null);
            }
        } catch (CameraAccessException e) {
            e.printStackTrace();
        }
}