GetView updating items outside of screen

Question

I have following code inside GetView method of my Custom adapter:

public override View GetView(int position, View convertView, ViewGroup parent)
    {
        var view = convertView ?? activity.LayoutInflater.Inflate(
                       Resource.Layout.ScannedTuListItem, parent, false);

        var scannedTu = view.FindViewById<TextView>(Resource.Id.scannedTu);

        var tuTxt = activity.Resources.GetString(Resource.String.tu);
        var custTxt = activity.Resources.GetString(Resource.String.customer);
        var orderTxt = activity.Resources.GetString(Resource.String.order);
        var targetBinTxt = activity.Resources.GetString(Resource.String.targetBin);

        scannedTu.Text = 
                        $"{tuTxt} {tus[position].No}" +
                        $"\n{custTxt} {tus[position].Customer} / {orderTxt} {tus[position].Order}" +
                        (string.IsNullOrEmpty(tus[position].TargetBin) ?
                        string.Empty : $"\n{targetBinTxt} {tus[position].TargetBin}");

        if (tus[position].AtPackingStation && !tus[position].Ready)
        {
            scannedTu.SetBackgroundColor(Color.Yellow);
            scannedTu.SetTextColor(Color.Black);
        }
        else if (tus[position].AtPackingStation && tus[position].Ready || tus[position].ScanOk == true)
        {
            scannedTu.SetBackgroundColor(Color.Green);
            scannedTu.SetTextColor(Color.Black);
        }
        else if (tus[position].ScanOk == false)
        {
            scannedTu.SetBackgroundColor(Color.Red);
            scannedTu.SetTextColor(Color.Black);
        }

        return view;
    }

When I change Property ScanOK and Ready to True, say, for the first 3 items in the list, it automatically sets the background color of items outside the screen also to Green.

How do I make it color only the first 3 items without affecting items off the screen?

Could you offer more code about your items of listview ? what ‘s mean about `tus[position].Ready ` `tus[position].ScanOk` `tus[position].AtPackingStation`? You could debug it, check `if/else` whether meet the requirement. — Leon, Feb 05 '19 at 02:34
@Leon Lu - MSFT I've debugged it already and e.g. for 10 items if only first 3 meet the critaria and are actually visible on screen it still changes background color of some of the other items. It seems to be doing it randomly... — bigb055, Feb 05 '19 at 10:20

score 0 · Answer 1 · edited Jun 20 '20 at 09:12

0

When I change Property ScanOK and Ready to True, say, for the first 3 items in the list, it automatically sets the background color of items outside the screen also to Green.

How do I make it color only the first 3 items without affecting items off the screen?

For that you will have to add an initial condition on the basis of position for eg

   If(position>2) //since integers start from zero
   return;

Also if you want to mark on the basis of how many list items are displayed on the screen you can check this SO answer

edited Jun 20 '20 at 09:12

Community

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1

answered Feb 05 '19 at 05:11

FreakyAli

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what if number of items to change color is larger than number of items visible on screen? I want all the items that meet certaing condition to change color even when off screen. How do I know the position of last visible item inside `GetView()`? – bigb055 Feb 05 '19 at 10:17
I have attached a Stack answer that handles that did you check it? – FreakyAli Feb 05 '19 at 10:53

GetView updating items outside of screen

1 Answers1