Android Studio – layout doesn't appear in activity_main of my app

i've tried with setContentView(viewBinding.getRoot()), but the result its the same. i've noticed that my customized topbar appers until the app launch the function, startCamera() I've also noticed that the customized topbar dissapear when in the startCamera, the execution reach this code

       camera=cameraProvider.bindToLifecycle(
            this, cameraSelector, preview, imageCapture)

private fun startCamera() {
    val cameraProviderFuture = ProcessCameraProvider.getInstance(this)

    cameraProviderFuture.addListener({
        // Used to bind the lifecycle of cameras to the lifecycle owner
        val cameraProvider: ProcessCameraProvider = cameraProviderFuture.get()

        // Preview
        val preview = Preview.Builder()
            .build()
            .also {
                it.setSurfaceProvider(viewBinding.viewFinder.surfaceProvider)
            }

        imageCapture = ImageCapture.Builder()
            .setCaptureMode(ImageCapture.CAPTURE_MODE_MAXIMIZE_QUALITY)
            .setFlashMode(ImageCapture.FLASH_MODE_AUTO)
            .build()

        // Select back camera as a default
        val cameraSelector = CameraSelector.DEFAULT_BACK_CAMERA

        try {
            // Unbind use cases before rebinding
            cameraProvider.unbindAll()

            // Bind use cases to camera
            camera=cameraProvider.bindToLifecycle(
                this, cameraSelector, preview, imageCapture)

            val autoFocusPoint = SurfaceOrientedMeteringPointFactory(1f, 1f)
                .createPoint(.5f, .5f)
            try {
                val autoFocusAction = FocusMeteringAction.Builder(
                    autoFocusPoint,
                    FocusMeteringAction.FLAG_AF
                ).apply {
                    //start auto-focusing after 1 seconds
                    setAutoCancelDuration(1000, TimeUnit.MILLISECONDS)
                }.build()
                camera.cameraControl.startFocusAndMetering(autoFocusAction)
            } catch (e: CameraInfoUnavailableException) {
                Log.d("ERROR", "cannot access camera", e)
            }
        } catch(exc: Exception) {
            Log.e(TAG, "Use case binding failed", exc)
        }

    }, ContextCompat.getMainExecutor(this))
}