lateinit property groupList for expandableListView has not been initialized-CodePudding

I created a Listadapter for an expandable ListView. This adapter needs a List and a HashMap. I tried to initalize those two in a fragment with lateinit, to display this expandable ListView with custom groups and childs. But when i launch the app they have not been initalized.

The error:

 lateinit property groupList has not been initialized

class MyClass: Fragment() {

rivate lateinit var ListAdapter: YearListViewAdapter
private lateinit var groupList: List\<String\>
private lateinit var childList: HashMap\<String, List\<String\>\>

override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)

    yearListAdapter = ListViewAdapter(this, groupList, childList) //the error occures in this line
    yearGoalList.setAdapter(ListAdapter)
    
    }
}

I dont redeclare the group and childList. I also tried to use the Listadapter later in the code but the proplem still occures.

CodePudding user response：

As the error message indicates, they are not initialized and you're passing uninitialized values. If at the beginning the list is empty and has no value I suggest doing like this:

    private val groupList: List<String> = emptyList()
    private val childList = hashMapOf<String, List<String>>()