Struggling with a list geofenceList in Kotlin

Question

I tracked my problem down to adding to my geofenceList.

this is a global variable

lateinit var geofenceList: MutableList<Geofence>

In onCreate I add to the list:

val latitude = -26.082586
val longitude = 27.777242
val radius = 10f
geofenceList.add(Geofence.Builder()
      .setRequestId("Toets")
      .setCircularRegion(latitude,longitude,radius)
      .setExpirationDuration(Geofence.NEVER_EXPIRE)
      .setTransitionTypes(Geofence.GEOFENCE_TRANSITION_ENTER)
      .build())

Every time I run the app the app closes as soon as it opens.

I tried changing it to a normal variable but I am not certain how to do it and keep it a global variable, and a List would be more useful.

Welcome to StackOverflow! It looks like your program is throwing an exception. When you run your app on your phone through Android Studio, you should see a run-tool window which should show you an exception. Please edit your question and paste the exception there or follow the advice in [this question](https://stackoverflow.com/questions/3988788/what-is-a-stack-trace-and-how-can-i-use-it-to-debug-my-application-errors) to solve your issue. Cheers :) — vatbub, Jan 20 '23 at 10:31

score 0 · Accepted Answer · answered Jan 20 '23 at 10:36

I just realized what your issue is: You never initialize your list. When you follow the advice in my comment, you should find a NullPointerException and here's how to fix it:

Firstly, try to avoid lateinit if possible. The compiler actually tries to find this problem for you and by using lateinit, you basically tell the compiler to shut up - even though the mistake is still there. INstead, you need to initialize your variable like so:

var geofenceList: MutableList<Geofence> = mutableListOf()

You could make it even shorter by removing the explicit type declaration:

var geofenceList = mutableListOf<Geofence>()

Struggling with a list geofenceList in Kotlin

1 Answers1