VideoCaptureManager.kt

class VideoCaptureManager ... LifecycleEventObserver {
    ...
    
    fun showPreview(previewState: PreviewState, cameraPreview: PreviewView = getCameraPreview()): View {
        getLifeCycleOwner().lifecycleScope.launchWhenResumed {
            val cameraProvider = cameraProviderFuture.await()
            cameraProvider.unbindAll()

            //Select a camera lens
            val cameraSelector: CameraSelector = CameraSelector.Builder()
                .requireLensFacing(previewState.cameraLens)
                .build()

            //Create Preview use case
            val preview: Preview = Preview.Builder()
                .setTargetResolution(previewState.size)
                .build()
                .apply { setSurfaceProvider(cameraPreview.surfaceProvider) }

            //Create Video Capture use case
            val recorder = Recorder.Builder().build()
            videoCapture = VideoCapture.withOutput(recorder)

            cameraProvider.bindToLifecycle(
                getLifeCycleOwner(),
                cameraSelector,
                preview,
                videoCapture
            ).apply {
                cameraControl.enableTorch(previewState.torchState == TorchState.ON)
            }
        }
        return cameraPreview
    }

    fun updatePreview(previewState: PreviewState, previewView: View) {
        showPreview(previewState, previewView as PreviewView)
    }

    private fun getCameraPreview() = PreviewView(getContext()).apply {
        layoutParams = ViewGroup.LayoutParams(
            ViewGroup.LayoutParams.MATCH_PARENT,
            ViewGroup.LayoutParams.MATCH_PARENT
        )
        keepScreenOn = true
    }
}