From 1fd1da699d09c9f4f5f74ca4c78a3611465a0de8 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Javier=20Su=C3=A1rez=20Ruiz?= <javiersuarezruiz@hotmail.com>
Date: Thu, 22 Mar 2018 20:16:11 +0100
Subject: [PATCH] Changes in ListViewRenderer to support source collection
 changes (add, remove, etc)

---
 Ooui.Forms/Renderers/ListViewRenderer.cs | 33 ++++++++++++++++++--
 Samples/ListView/RefreshListView.xaml    | 29 ++++++++++++++++++
 Samples/ListView/RefreshListView.xaml.cs | 16 ++++++++++
 Samples/ListView/RefreshListViewModel.cs | 38 ++++++++++++++++++++++++
 Samples/Program.cs                       |  1 +
 Samples/RefreshListViewSample.cs         | 21 +++++++++++++
 Samples/Samples.csproj                   |  7 +++++
 7 files changed, 142 insertions(+), 3 deletions(-)
 create mode 100644 Samples/ListView/RefreshListView.xaml
 create mode 100644 Samples/ListView/RefreshListView.xaml.cs
 create mode 100644 Samples/ListView/RefreshListViewModel.cs
 create mode 100644 Samples/RefreshListViewSample.cs

diff --git a/Ooui.Forms/Renderers/ListViewRenderer.cs b/Ooui.Forms/Renderers/ListViewRenderer.cs
index efaf229..368ae06 100644
--- a/Ooui.Forms/Renderers/ListViewRenderer.cs
+++ b/Ooui.Forms/Renderers/ListViewRenderer.cs
@@ -1,5 +1,6 @@
 using Ooui.Forms.Extensions;
 using System.Collections.Generic;
+using System.Collections.Specialized;
 using System.ComponentModel;
 using System.Linq;
 using Xamarin.Forms;
@@ -22,6 +23,12 @@ namespace Ooui.Forms.Renderers
 
         protected override void OnElementChanged(ElementChangedEventArgs<ListView> e)
         {
+            if (e.OldElement != null) 
+            {
+                var templatedItems = TemplatedItemsView.TemplatedItems;
+                templatedItems.CollectionChanged -= OnCollectionChanged;
+            }
+
             if (e.NewElement != null)
             {
                 if (Control == null)
@@ -31,7 +38,10 @@ namespace Ooui.Forms.Renderers
                     SetNativeControl(_listView);
                 }
 
-                UpdateItems();
+                var templatedItems = TemplatedItemsView.TemplatedItems;
+                templatedItems.CollectionChanged += OnCollectionChanged;
+
+                UpdateItems ();
                 UpdateBackgroundColor();
             }
 
@@ -52,13 +62,25 @@ namespace Ooui.Forms.Renderers
 
             base.Dispose(disposing);
 
-            if (disposing && !_disposed)
+            if (disposing && !_disposed) 
             {
+
+                if (Element != null) 
+                {
+                    var templatedItems = TemplatedItemsView.TemplatedItems;
+                    templatedItems.CollectionChanged -= OnCollectionChanged;
+                }
+
                 _disposed = true;
             }
         }
 
-		private void UnsubscribeCellClicks()
+        private void OnCollectionChanged (object sender, NotifyCollectionChangedEventArgs e)
+        {
+            UpdateItems ();
+        }
+
+        private void UnsubscribeCellClicks()
 		{
 			foreach (var c in _cells)
 			{
@@ -71,6 +93,11 @@ namespace Ooui.Forms.Renderers
 			UnsubscribeCellClicks();
             _cells.Clear();
 
+            foreach (var child in _listView.Children) 
+            {
+                _listView.RemoveChild (child);
+            }
+
             var items = TemplatedItemsView.TemplatedItems;
 
             if (!items.Any())
diff --git a/Samples/ListView/RefreshListView.xaml b/Samples/ListView/RefreshListView.xaml
new file mode 100644
index 0000000..45eb936
--- /dev/null
+++ b/Samples/ListView/RefreshListView.xaml
@@ -0,0 +1,29 @@
+<?xml version="1.0" encoding="utf-8" ?>
+<ContentPage
+    xmlns="http://xamarin.com/schemas/2014/forms"
+    xmlns:x="http://schemas.microsoft.com/winfx/2009/xaml"
+    x:Class="Samples.RefreshListView">
+    <ContentPage.Content>
+        <StackLayout>
+            <ListView
+                ItemsSource="{Binding Data}"
+                HeightRequest="200">
+                <ListView.ItemTemplate>
+                    <DataTemplate>
+                        <ViewCell>
+                            <Label
+                                Text="{Binding .}" />
+                        </ViewCell>
+                    </DataTemplate>
+                </ListView.ItemTemplate>
+            </ListView>
+            <StackLayout>
+                <Entry
+                    Text="{Binding Input}" />
+                <Button
+                    Text="Add Item"
+                    Command="{Binding AddCmd}" />
+            </StackLayout>
+        </StackLayout>
+    </ContentPage.Content>
+</ContentPage>
diff --git a/Samples/ListView/RefreshListView.xaml.cs b/Samples/ListView/RefreshListView.xaml.cs
new file mode 100644
index 0000000..4dd02f5
--- /dev/null
+++ b/Samples/ListView/RefreshListView.xaml.cs
@@ -0,0 +1,16 @@
+using Xamarin.Forms;
+using Xamarin.Forms.Xaml;
+
+namespace Samples
+{
+    [XamlCompilation(XamlCompilationOptions.Compile)]
+	public partial class RefreshListView : ContentPage
+	{
+		public RefreshListView ()
+		{
+			InitializeComponent ();
+
+            BindingContext = new RefreshListViewModel ();
+        }
+	}
+}
diff --git a/Samples/ListView/RefreshListViewModel.cs b/Samples/ListView/RefreshListViewModel.cs
new file mode 100644
index 0000000..d5d2c7e
--- /dev/null
+++ b/Samples/ListView/RefreshListViewModel.cs
@@ -0,0 +1,38 @@
+using System.Collections.ObjectModel;
+using System.Windows.Input;
+using Xamarin.Forms;
+
+namespace Samples
+{
+    public class RefreshListViewModel : BindableObject
+    {
+        public ICommand AddCmd => new Command (() => {
+            Data.Add (Input);
+            OnPropertyChanged (nameof (Data));
+        });
+
+        private string _input;
+
+        public string Input
+        {
+            get => _input;
+            set
+            {
+                _input = value;
+                OnPropertyChanged ();
+            }
+        }
+
+        private ObservableCollection<string> _data = new ObservableCollection<string>();
+
+        public ObservableCollection<string> Data
+        {
+            get => _data;
+            set
+            {
+                _data = value;
+                OnPropertyChanged ();
+            }
+        }
+    }
+}
diff --git a/Samples/Program.cs b/Samples/Program.cs
index 4478211..e77bab4 100644
--- a/Samples/Program.cs
+++ b/Samples/Program.cs
@@ -34,6 +34,7 @@ namespace Samples
             new DotMatrixClockSample().Publish();
             new EditorSample().Publish();
             new MonkeysSample().Publish();
+            new RefreshListViewSample ().Publish ();
             new SearchBarSample().Publish();
             new SliderSample().Publish();
             new SwitchListViewSample().Publish();
diff --git a/Samples/RefreshListViewSample.cs b/Samples/RefreshListViewSample.cs
new file mode 100644
index 0000000..8a52f6c
--- /dev/null
+++ b/Samples/RefreshListViewSample.cs
@@ -0,0 +1,21 @@
+using Ooui;
+using Xamarin.Forms;
+
+namespace Samples
+{
+    public class RefreshListViewSample : ISample
+    {
+        public string Title => "Xamarin.Forms RefreshListView";
+
+        public Ooui.Element CreateElement ()
+        {
+            var page = new RefreshListView();
+            return page.GetOouiElement ();
+        }
+
+        public void Publish ()
+        {
+            UI.Publish ("/refreshlistview", CreateElement);
+        }
+    }
+}
diff --git a/Samples/Samples.csproj b/Samples/Samples.csproj
index effd0d6..1492bbd 100644
--- a/Samples/Samples.csproj
+++ b/Samples/Samples.csproj
@@ -32,6 +32,9 @@
     <Compile Update="DisplayAlertPage.xaml.cs">
       <DependentUpon>DisplayAlertPage.xaml</DependentUpon>
     </Compile>
+    <Compile Update="ListView\RefreshListView.xaml.cs">
+      <SubType>Code</SubType>
+    </Compile>
   </ItemGroup>
 	
   <ItemGroup>
@@ -44,6 +47,9 @@
     <EmbeddedResource Update="DotMatrixClock\DotMatrixClockPage.xaml">
       <Generator>MSBuild:Compile</Generator>
     </EmbeddedResource>
+    <EmbeddedResource Update="ListView\RefreshListView.xaml">
+      <Generator>MSBuild:UpdateDesignTimeXaml</Generator>
+    </EmbeddedResource>
     <EmbeddedResource Update="Monkeys\MonkeysView.xaml">
       <Generator>MSBuild:Compile</Generator>
     </EmbeddedResource>
@@ -59,6 +65,7 @@
     <None Remove="BugSweeper\Images\RedBug.png" />
     <None Remove="BugSweeper\Images\Xamarin120.png" />
     <None Remove="DotMatrixClock\DotMatrixClockPage.xaml" />
+    <None Remove="ListView\RefreshListView.xaml" />
     <None Remove="Monkeys\Images\Baboon.jpg" />
     <None Remove="Monkeys\Images\BlueMonkey.jpg" />
     <None Remove="Monkeys\Images\Capuchin.jpg" />