added CollectionView fix for children leak

Author: roubachof

Sample/ShadowsSample.Android/CollectionViewLeakRenderer.cs

@@ -0,0 +1,80 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+using Android.App;
+using Android.Content;
+using Android.OS;
+using Android.Runtime;
+using Android.Views;
+using Android.Widget;
+
+using ShadowsSample.Droid;
+
+using Sharpnado.Presentation.Forms.Droid.Helpers;
+using Sharpnado.Shades.Droid;
+
+using Xamarin.Forms;
+using Xamarin.Forms.Platform.Android;
+
+[assembly: ExportRenderer(typeof(CollectionView), typeof(CollectionViewLeakRenderer))]
+
+namespace ShadowsSample.Droid
+{
+    public class CollectionViewLeakRenderer : CollectionViewRenderer
+    {
+        public CollectionViewLeakRenderer(Context context)
+            : base(context)
+        {
+        }
+
+        protected override void Dispose(bool disposing)
+        {
+            System.Diagnostics.Debug.WriteLine(ItemsViewAdapter);
+
+            if (!disposing)
+            {
+                base.Dispose(false);
+                return;
+            }
+
+            var children = GetChildren();
+            base.Dispose(true);
+            DisposeChildren(children);
+        }
+
+        private ItemContentView[] GetChildren()
+        {
+            System.Diagnostics.Debug.WriteLine($"GetChildren() => count: {ChildCount}");
+            var result = new ItemContentView[ChildCount];
+            for (int childCount = ChildCount, i = 0; i < childCount; ++i)
+            {
+                result[i] = (ItemContentView)GetChildAt(i);
+            }
+
+            return result;
+        }
+
+        private void DisposeChildren(ItemContentView[] children)
+        {
+            System.Diagnostics.Debug.WriteLine($"DisposeChildren() => count: {children.Length}");
+            for (int childCount = children.Length, i = 0; i < childCount; ++i) 
+            {
+                var itemContentView = children[i];
+                if (!itemContentView.IsNullOrDisposed())
+                {
+                    // System.Diagnostics.Debug.WriteLine(itemContentView.DumpHierarchy(true));
+                    var view = itemContentView.GetChildAt(0);
+                    if (!view.IsNullOrDisposed())
+                    {
+                        view.Dispose();
+                    }
+
+                    itemContentView.RemoveAllViews();
+                    itemContentView.Dispose();
+                }
+            }
+        }
+    }
+}

Sample/ShadowsSample.Android/MainApplication.cs

@@ -0,0 +1,43 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Text;
+
+using Android.App;
+using Android.Content;
+using Android.OS;
+using Android.Runtime;
+using Android.Views;
+using Android.Widget;
+
+using Square.LeakCanary;
+
+namespace ShadowsSample.Droid
+{
+    [Application]
+    internal class MainApplication : Application
+    {
+        private RefWatcher _refWatcher;
+
+        protected MainApplication(IntPtr javaReference, JniHandleOwnership transfer) : base(javaReference, transfer)
+        {
+        }
+
+        public override void OnCreate()
+        {
+            base.OnCreate();
+            SetupLeakCanary();
+        }
+
+        protected void SetupLeakCanary()
+        {
+            if (LeakCanaryXamarin.IsInAnalyzerProcess(this))
+            {
+                // This process is dedicated to LeakCanary for heap analysis.
+                // You should not init your app in this process.
+                return;
+            }
+            _refWatcher = LeakCanaryXamarin.Install(this);
+        }
+    }
+}