ListView cant access last element of the list

Issue

I have a list of objects I want to list on the screen and im using a ListView with an adapter. And I have added a listViewItem click event like this:

lstViewData.ItemClick += OnListViewItemClicked;

The event itself:

    private void OnListViewItemClicked(object sender, AdapterView.ItemClickEventArgs e)
    {
        for (int i = 0; i < lstViewData.Count; i++)
        {
            if (e.Position == i)
                lstViewData.GetChildAt(i).SetBackgroundColor(Android.Graphics.Color.Gray);
            else
                lstViewData.GetChildAt(i).SetBackgroundColor(Android.Graphics.Color.Transparent);
        }

The lstViewData has 5 elements in it. So for the purpose of the for loop means i goes from 0 to 4. Which it does.

The issue is once i gets to the last element of the list I get a error saying Reference not set to an instance of an object. Aka nullreferenceException If I remember correctly.

I went to debugging and saw that all 5 elements of the list were not null and all was well and that the index is never out of range. So I am lost and I dont know why my code breaks when attempting to access the last element of the list.

Solution

The GetChildAt(index) method can only access visible elements of the ListView. Try this in the for loop:

for (int i = 0; i <= f_listView.getLastVisiblePosition() - f_listView.getFirstVisiblePosition(); i++)

Answered By - Zserbinator