Check runtime permissions in ViewModel

Fragment.kt

class VehicleDetailsFragmentKt : BaseFragment() {

    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        
        observeLiveData() 
      
        return inflater.inflate(getLayoutResId(), container, false);
    }

      private fun observeLiveData() {

        vehicleViewModel.eventRequestPermission.observe(viewLifecycleOwner, Observer {
            it.getContentIfNotHandled()?.let { permission ->
                when (permission.requestCode) {
                    Constants.REQUEST_CODE_CAMERA_PERMISSION ->
                        //see PermissionExtension.kt
                        requestRuntimePermissions(permission.requestCode)
                }
            }
        })


    }
  
  
      override fun onRequestPermissionsResult(requestCode: Int, permissions: Array<out String>, grantResults: IntArray) {
        var isGranted = false
        for (result in grantResults) {
            if (result == PackageManager.PERMISSION_GRANTED) {
                isGranted = true
            } else {
                isGranted = false
                break
            }
        }

        when (requestCode) {
            Constants.REQUEST_CODE_CAMERA_PERMISSION -> {
               //see ViewModel.kt
                vehicleViewModel.onEventRequestPermissionsResult(requestCode, isGranted)
            }
            else -> super.onRequestPermissionsResult(requestCode, permissions, grantResults)
        }
    }
  
  
}

PermissionExtension.kt

data class Permission(val requestCode: Int) {
    var isGranted: Boolean
        set(value) {
            if (value) grantedPermissions[this.requestCode] = this
            else grantedPermissions.remove(this.requestCode)
        }
        get() {
            if (grantedPermissions.isNullOrEmpty()) return false
            return grantedPermissions[this.requestCode] != null
        }
}


/**
 * It removes permissions from the list of already granted permissions
 */
fun clearGrantedPermissions() {
    grantedPermissions.clear()
}

fun Fragment.requestRuntimePermissions(requestCode: Int) {
    when (requestCode) {
        Constants.REQUEST_CODE_CAMERA_PERMISSION -> requestPermissions(permissionsCaptureVideo, requestCode)
    }

}

private var grantedPermissions = HashMap<Int, Permission>()

private val permissionsCaptureVideo =
    arrayOf(
        Manifest.permission.CAMERA,
        Manifest.permission.RECORD_AUDIO,
        Manifest.permission.WRITE_EXTERNAL_STORAGE
    )

ViewModel.kt

class VehicleDetailsViewModel : : BaseViewModel(), LifecycleObserver {
  
    private val _eventRequestPermission = MutableLiveData<Event<Permission>>()
    val eventRequestPermission: LiveData<Event<Permission>> = _eventRequestPermission
  
    @OnLifecycleEvent(Lifecycle.Event.ON_STOP)
    fun onStopView() {
        //clear granted permissions to check them again when view will be visible
        clearGrantedPermissions()
    }
  
    //it calls from xml layout
    fun onClickCaptureButton() {

        //check are permissions to capture video and photo granted
        var permissionRequestCode = Constants.REQUEST_CODE_CAMERA_PERMISSION
        var permission = Permission(permissionRequestCode)
        if (!permission.isGranted) {
            //ask permission
            _eventRequestPermission.value = Event(permission)
            return
        }

        //check is permission to draw overlays granted
        permissionRequestCode = Constants.REQUEST_CODE_DRAW_OVER_APPS_PERMISSION
        permission = Permission(permissionRequestCode)
        if (!permission.isGranted) {
            //ask permission
            _eventRequestPermission.value = Event(permission)
            return
        }

        //show menu to choose video or photo capture
        showCaptureOptions()
    }
  
      fun onEventRequestPermissionsResult(requestCode: Int, isGranted: Boolean) {
        Permission(requestCode).isGranted = isGranted
        
        when (requestCode) {
            Constants.REQUEST_CODE_CAMERA_PERMISSION -> {
                if (!isGranted) {
                    //show alert
                    _eventNavigateTo.value = Event(Navigation(NavigateTo.ALERT_CAPTURE_PERMISSION_DENIED))
                } else {
                    //continue with capture
                    onClickCaptureButton()
                }
            }
        }
    }
  
  
  private fun showCaptureOptions() {
    //do something here
  }
}