How can a scroll a specific row or section to the top of a Xamarin.Forms.ListView - xamarin

Question

I have a Xamarin.Forms.ListView that contains events that are grouped by date. There are events that occur in future and events that occur in the past.
Users would like to have their screen load with a future event closest to the current date in view so that they do not need to manually scroll down to view it.
What options do I have with a Xamarin.Forms.ListView to accomplish this for iOS and Android users?

Answer 1

I have made some progress. I am able to accomplish my goal in iOS by creating a CustomListView and an iOS render to support it.
In Xamarin.Forms you create a CustomListView then after you have loaded the list you an call ScrollToRow(item,section) to manually scroll to the row you need.
In iOS the renderer maps the method to UITableView message ScrollToRow(...);
For Android I still need to create the renderer but I do know that I need to map to the calls getListView().setSelection(...); or getListView().smoothScrollToPosition(...);
I am sure there is a more elegant way to do this but for now it is getting the job done
Source For: Common.CustomListView
using System;
using Xamarin.Forms;
namespace Common {
public class CustomListView : ListView {
public Action<int, int, bool> ScrollToRowDelegate { get; set; }
public void ScrollToRow(int itemIndex, int sectionIndex = 0, bool animated = false) {
if (ScrollToRowDelegate != null) {
ScrollToRowDelegate (itemIndex, sectionIndex, animated);
}
}
}
}
iOS Renderer Source:YourApplication.iOS.Renderers.CustomListViewRenderer
using System;
using Xamarin.Forms.Platform.iOS;
using Xamarin.Forms;
using Common;
using MonoTouch.UIKit;
using MonoTouch.Foundation;
using YourApplication.iOS.Renderers;
[assembly: ExportRenderer (typeof(CustomListView), typeof(CustomListViewRenderer))]
namespace YourApplication.iOS.Renderers
{
public class CustomListViewRenderer : ListViewRenderer
{
protected override void OnModelSet (VisualElement view) {
base.OnModelSet (view);
var listView = view as CustomListView;
listView.ScrollToRowDelegate = (itemIndex, sectionIndex, animated) => {
ScrollToRow(itemIndex, sectionIndex, animated);
};
}
private void ScrollToRow(int itemIndex, int sectionIndex, bool animated) {
var tableView = this.Control as UITableView;
var indexPath = NSIndexPath.FromItemSection (itemIndex, sectionIndex);
tableView.ScrollToRow (indexPath, UITableViewScrollPosition.Top, animated);
}
}
}