Reactwidget @mauron85/react-native-background-geolocation in the Fitness App throws an error

What causes this error “null is not an object”: An error occurred while executing an action of FitnessTracker.Run_NewEdit.actionButton1: null is not an object (evaluating 'RNBackgroundGeolocation.configure') In the Fitness tracker app of this Mendix webinar they use the react-native javascript '@mauron85/react-native-background-geolocation'; When I downloaded their code from, started the project locally, and did what was done in the video, then action-button 'Start Run’ results in the error message. This tells me, if I am not mistaken, that while executing the react-native javascript the object passed on to the .configure function is NULL. Does anybody have any idea what causes this error? The parameters all have values as in their demo. URL I have set to the IP of my locally running app. RunID is passed along fine. I feel like there is a step missing in the installation process of the app.  
2 answers

The module react-native-background-navigation is not included in Make it Native. Since that module contains native code, it must be added to your mobile developer app. So:

  1. Build a custom developer app like this:
  2. Add react-native-background-navigation to the app just like this article adds react-native-nfc-manager:



Hi Tim,

I made the app for the webinar so yes I agree with Erics answer above, connect with me on the mendix community slack and i can send you the make it native clone we used in the demo :)