Custom adapter sample

Samples/Example.Droid/Fragments/ExampleRecyclerViewFragment.cs

@@ -1,4 +1,5 @@
 using System;
+using System.Windows.Input;
 using Android.OS;
 using Android.Runtime;
 using Android.Support.Design.Widget;
@@ -9,6 +10,8 @@
 using MvvmCross.Droid.Support.V7.RecyclerView;
 using MvvmCross.Droid.Support.V4;
 using Example.Core.ViewModels;
+using MvvmCross.Binding.Droid.BindingContext;
+using MvvmCross.Core.ViewModels;
 using MvvmCross.Droid.Shared.Attributes;
 
 namespace Example.Droid.Fragments
@@ -26,6 +29,13 @@ public override View OnCreateView(LayoutInflater inflater, ViewGroup container,
             var recyclerView = view.FindViewById<MvxRecyclerView>(Resource.Id.my_recycler_view);
             if (recyclerView != null)
             {
+                // User our custom adapter
+                // Doing this will make things break on call on
+                // MyCustomAdapter::OnCreateViewHolder because MyCustomAdapter::BindingContext
+                // is null...
+                var adapter = new MyCustomAdapter {ItemCustomClick = new MvxCommand(DoItemCustomClick)};
+
+                recyclerView.Adapter = adapter;
                 recyclerView.HasFixedSize = true;
                 var layoutManager = new LinearLayoutManager(Activity);
                 recyclerView.SetLayoutManager(layoutManager);
@@ -47,6 +57,12 @@ public override View OnCreateView(LayoutInflater inflater, ViewGroup container,
             return view;
         }
 
+        private void DoItemCustomClick()
+        {
+            // This is never executed because of NullReference on ViewHolder creation
+            Toast.MakeText(Activity, "Here I am", ToastLength.Short).Show();
+        }
+
         public override void OnDestroyView()
         {
             base.OnDestroyView();
@@ -55,5 +71,66 @@ public override void OnDestroyView()
         }
 
         protected override int FragmentId => Resource.Layout.fragment_example_recyclerview;
+
+        ////////////////////////////////////////////////////////////////////////
+        // Let's create a custom adapter to use a custom ViewHolder (in order
+        // to add custom bindings for example).
+        ////////////////////////////////////////////////////////////////////////
+        public class MyCustomAdapter : MvxRecyclerAdapter
+        {
+            public ICommand ItemCustomClick { get; set; }
+
+            public override RecyclerView.ViewHolder OnCreateViewHolder(ViewGroup parent, int viewType)
+            {
+                //////////////////////////////////////////////////////////////////////////////////////
+                // Here is the NullReference exception : BindingContext is null
+                var itemBindingContext = new MvxAndroidBindingContext(parent.Context, BindingContext.LayoutInflaterHolder);
+
+                return new MyCustomViewHolder(InflateViewForHolder(parent, viewType, itemBindingContext), itemBindingContext)
+                {
+                    Click = ItemClick,
+                    LongClick = ItemLongClick,
+                    CustomClick = ItemCustomClick
+                };
+            }
+
+
+        }
+    }
+
+    public class MyCustomViewHolder : MvxRecyclerViewHolder
+    {
+        public MyCustomViewHolder(View itemView, MvxAndroidBindingContext bindingContext)
+            : base(itemView, bindingContext)
+        {
+        }
+
+        private bool _customClickDefined;
+        private ICommand _customClick;
+
+        public ICommand CustomClick
+        {
+            get
+            {
+                return _customClick;
+            }
+
+            set
+            {
+                _customClick = value;
+                if (null != _customClick && !_customClickDefined)
+                {
+                    _customClickDefined = true;
+                    ///////////////////////////////////////////////////////////////////////////
+                    // Concrete sample of why I would want to customize the ViewHolder: adding 
+                    // custom click binding on a given view
+                    ///////////////////////////////////////////////////////////////////////////
+
+                    //var view = ItemView.FindViewById<ImageView>(Resource.Id.MyCustomImage);
+                    //if (null != view)
+                    //    view.CustomClickEvent = CustomClick;
+                }
+            }
+        }
     }
 }