README.md

How to add a jump list with xamarin.forms listview

You can add jump list using Xamarin.Forms ListView by tap on the indexed letter (group key) and scroll to the respective group GroupHeaderItem by passing group key index in ScrollToIndex method like contact list. You can refer following article explains you how to create jump list with group key and scroll to tapped item.

https://www.syncfusion.com/kb/11021/how-to-add-a-jump-list-with-xamarin-forms-listview

Creates panel to shows the group key as indexed vertically.

<ContentPage xmlns:syncfusion="clr-namespace:Syncfusion.ListView.XForms;assembly=Syncfusion.SfListView.XForms" >
    <ContentPage.Content>
       <Grid >
          <syncfusion:SfListView x:Name="listView" Grid.Row="0">
                <syncfusion:SfListView.ItemTemplate>
                          <DataTemplate>
                                     <ViewCell>
                                             <Grid>
                                                  <Image Source="{Binding ContactImage}" Grid.Column="0"/>
                                                        <StackLayout Orientation="Vertical" Grid.Column="1">
                                                                     <Label Text="{Binding ContactName}"/>
                                                                     <Label Text="{Binding ContactNumber}"/>
                                                        </StackLayout>
                                               </Grid>
                                             <StackLayout HeightRequest="1" BackgroundColor="LightGray"/>
                                     </ViewCell>
                          </DataTemplate>
                </syncfusion:SfListView.ItemTemplate>                
            </syncfusion:SfListView>
            <Grid x:Name="IndexPanelGrid" Grid.Row="0"  VerticalOptions="CenterAndExpand" HorizontalOptions="End" />
         </Grid>
    </ContentPage.Content>
</ContentPage>

Creates and populate the index panel with index labeled from the Group key.

ListView.Loaded += ListView_Loaded;

private void ListView_Loaded(object sender, ListViewLoadedEventArgs e)
{
     var groupcount = this.ListView.DataSource.Groups.Count;
     for (int i = 0; i < groupcount; i++)
     {
        label = new Label();  
        GroupResult group = ListView.DataSource.Groups[i];
        label.Text = group.Key.ToString();
        indexPanelGrid.Children.Add(label, 0, i);
        var labelTapped = new TapGestureRecognizer() { Command = new Command<object>(OnTapped), CommandParameter = label };
        label.GestureRecognizers.Add(labelTapped);
     }
}

On tapping the group key value loaded in the index panel, you can scroll the listview to the respective group by comparing all GroupHeader’s Key value like below.

private void OnTapped(object obj)
{
    if (previousLabel != null)
    {
      previousLabel.TextColor = Color.DimGray;
    }
    var label = obj as Label;
    var text = label.Text;
    label.TextColor = Color.Red;
    for (int i = 0; i < ListView.DataSource.Groups.Count; i++)
    {
        var group = ListView.DataSource.Groups[i];

        if (group.Key == null)
          App.Current.MainPage.DisplayAlert("Message", "Group not available", "ok");
        if ((group.Key != null && group.Key.Equals(text)))
        {
                  ListView.LayoutManager.ScrollToRowIndex (ListView.DataSource.DisplayItems.IndexOf(group), true);
         }
     }
     previousLabel = label;
}

OutPut