I'm using FreshMvvm with an application that is almost completely data driven. We have many places where a repeater type view is highly useful (a list of elements without scrolling baked in). I have been using a modified version of a repeater view I found in another forum post here, and included my code for the view below.
It's been working great until today when I discovered that using this somehow broke the ability to add a tap gesture to an image in a list item. The following XAML works just fine outside the repeater, but not inside.
<Image Source="GreenStar.png"
WidthRequest="40"
HeightRequest="40"
IsVisible="{Binding Acknowledged}">
<Image.GestureRecognizers>
<TapGestureRecognizer
Command="{Binding UnacknowledgeEventCommand}"
CommandParameter="{Binding .}" />
</Image.GestureRecognizers>
</Image>
Any help on how I can enable gestures within the RepeaterView would be gratefully appreciated
Btw, it's immensely frustrating that we have made it this far into the life of Xamarin Forms without a native RepeaterView
using System;
using System.Collections;
using System.Collections.Generic;
using System.Collections.Specialized;
using Xamarin.Forms;
public delegate void RepeaterViewItemAddedEventHandler(object sender, RepeaterViewItemAddedEventArgs args);
// in lieu of an actual Xamarin Forms ItemsControl, this is a heavily modified version of code from https://forums.xamarin.com/discussion/21635/xforms-needs-an-itemscontrol
public class RepeaterView : StackLayout
{
public static readonly BindableProperty ItemsSourceProperty = BindableProperty.Create(
"ItemSource",
typeof(IEnumerable),
typeof(RepeaterView),
new List<object>(),
BindingMode.OneWay,
propertyChanged: ItemsChanged);
public static readonly BindableProperty ItemTemplateProperty = BindableProperty.Create(
"ItemTemplate",
typeof(DataTemplate),
typeof(RepeaterView),
default(DataTemplate));
public event RepeaterViewItemAddedEventHandler ItemCreated;
public IEnumerable ItemsSource
{
get { return (IEnumerable)GetValue(ItemsSourceProperty); }
set { SetValue(ItemsSourceProperty, value); }
}
public DataTemplate ItemTemplate
{
get {
return (DataTemplate)GetValue(ItemTemplateProperty);
}
set { SetValue(ItemTemplateProperty, value); }
}
private static void ItemsChanged(BindableObject bindable, object oldValue, object newValue)
{
try
{
var control = (RepeaterView)bindable;
var oldObservableCollection = oldValue as INotifyCollectionChanged;
if (oldObservableCollection != null)
{
oldObservableCollection.CollectionChanged -= control.OnItemsSourceCollectionChanged;
}
var newObservableCollection = newValue as INotifyCollectionChanged;
if (newObservableCollection != null)
{
newObservableCollection.CollectionChanged += control.OnItemsSourceCollectionChanged;
}
control.Children.Clear();
if (newValue != null)
{
foreach (var item in (IEnumerable)newValue)
{
var view = control.CreateChildViewFor(item);
control.Children.Add(view);
control.OnItemCreated(view);
}
}
control.UpdateChildrenLayout();
control.InvalidateLayout();
}catch(Exception e){
throw;
}
}
protected virtual void OnItemCreated(View view) =>
this.ItemCreated?.Invoke(this, new RepeaterViewItemAddedEventArgs(view, view.BindingContext));
private void OnItemsSourceCollectionChanged(object sender, NotifyCollectionChangedEventArgs e)
{
var invalidate = false;
if (e.OldItems != null)
{
this.Children.RemoveAt(e.OldStartingIndex);
invalidate = true;
}
if (e.NewItems != null)
{
for (var i = 0; i < e.NewItems.Count; ++i)
{
var item = e.NewItems[i];
var view = this.CreateChildViewFor(item);
this.Children.Insert(i + e.NewStartingIndex, view);
OnItemCreated(view);
}
invalidate = true;
}
if (invalidate)
{
this.UpdateChildrenLayout();
this.InvalidateLayout();
}
}
private View CreateChildViewFor(object item)
{
this.ItemTemplate.SetValue(BindableObject.BindingContextProperty, item);
return (View)this.ItemTemplate.CreateContent();
}
}
public class RepeaterViewItemAddedEventArgs : EventArgs
{
private readonly View view;
private readonly object model;
public RepeaterViewItemAddedEventArgs(View view, object model)
{
this.view = view;
this.model = model;
}
public View View => this.view;
public object Model => this.model;
}
_DESENV\Droid\Path\Config.cs 10