fun showCamera(view: View) {
      Log.i(TAG, "Show camera button pressed.")
      if (ContextCompat.checkSelfPermission(thisActivity,
      Manifest.permission.CAMERA)
      != PackageManager.PERMISSION_GRANTED) {
         showCameraPreview()
       }
       else {
          requestPermissionLauncher.launch(Manifest.permission.CAMERA)
       }
  }