LazyColumn items key not responding to my code in Kotlin

Question

I am making a change in my List in the LazyColumn and added a key to the items property expecting to refresh the LazyColumn with the new List. But the LazyColumn does not refresh.

What do you suggest?

I have the following code segments:

class colNames(
val name:String,
val id:String
)

var colparent:List<colNames> = emptyList<colNames>()

//Process filling the List
var tempList: MutableList<colNames>
//Some code
colparent = tempList.toList()

LazyColumn(modifier = Modifier.padding(top = 36.dp)) 
{
itemsIndexed(
 items = colparent,
 key = { _, item -> item.id },
) { ind, item ->
    Text(
         text = item.name,
         modifier = Modifier
              .clickable(
                 onClick = {colparent = reorderNamesList(colparent, ind)} //This is a test function that changes the item position in the list ramdomly by the index
               )
    )
  }
}

Answer 1

I found the solution for my question.

I had:

var colparent by remember { mutableStateOf<List<colNames>>(emptyList<colNames>()) }

Then change to:

var colparent:List<colNames> = emptyList<colNames>()

Neither work. Finally I found an article: "Exploring Jetpack Compose LazyList animations" with a full example and notice that the problem was that I needed a MutableStateList no just a MutableState.

The final code is:

val listItems = remember { colparent.toMutableStateList() }  //THIS IS THE KEY                      
                                               
LazyColumn(modifier = Modifier.padding(top = 36.dp)) 
{
   itemsIndexed(
        items = listItems ,
        key = { _, item -> item.id },
   ) { ind, item ->
       Text(
            text = item.name,
            modifier = Modifier
               .clickable(
                  onClick = {
                     colparent = reorderNamesList(colparent, ind) 
                     //Above is a test function that changes the item position 
                     //in the list ramdomly by the index
                     colparent.forEachIndexed { id, x -> listItems[id] = x } 
                     //This is part of the solution. 
                     //Now Modify listItems, since is a State List the LacyColumn key statement 
                     //detects the State change thus the LazyColumn refreshes.
                  } 
               )
       )
    }
}