ListView项目中的mytimer android xamarin

Question

I have no idea how to change the value of items in listview every second. I have a listview with several items, items are added by the user and have a random place in listview (because they are added by the user). For example, ram size, storage, etc. items every time have a new value. How can I update the value of the items?

My listview code:

items = new List<string>();
        btn.Click += delegate
        {
            items.Add(myip.Text);
            ArrayAdapter<string> adapter = new ArrayAdapter<string>(this, Android.Resource.Layout.SimpleExpandableListItem1, items);

            listnames.Adapter = adapter;
        };

Answer 1

how can update value of items?

The recommended way is to create your own ArrayAdapter and override the GetItem like below:

public class MyArrayAdapter:ArrayAdapter
{
    private Context context;
    private int layoutId, textViewId;
    List<string> mList;
    public MyArrayAdapter(Context c,int layoutId,int textViewId, List<string> list) : base(c, layoutId,textViewId,list)
    {
        mList = list;
        context = c;
        this.layoutId = layoutId;
        this.textViewId = textViewId;
    }

    public override Java.Lang.Object GetItem(int position)
    {
        return mList[position];
    }
}

Then you can update the value at certain position by update the source List:

list[3] = "Edit Row";
adapter.NotifyDataSetChanged();

The other workaround is to remove the certain row and then insert a new row:

adapter.Remove(list[3]);
adapter.Insert("New Row", 3);
//the source list should also be updated.
list[3] = "New Row";
adapter.NotifyDataSetChanged();

Update:

To change the data every second you can use a recursive function to accomplish that:

int index=1;
...
void ChangeData()
{
    Task.Delay(1000).ContinueWith(t => {
        list[3] = "Edit Row" + index;
        adapter.NotifyDataSetChanged();
        index++;
        ChangeData();//recursive happens here
    },TaskScheduler.FromCurrentSynchronizationContext());
}