Merge pull request #1 from gianlucaparadise/recycler-getItemViewType-…

…handling

Recycler get item view type handling

GalaSoft.MvvmLight/GalaSoft.MvvmLight.AndroidSupport/Helpers/ExtensionsAndroid2.cs

@@ -41,19 +41,22 @@ public static class ExtensionsAndroid2
         /// <param name="bindViewHolderDelegate">A delegate to the method used to bind the view to the corresponding item.</param>
         /// <param name="createViewHolderDelegate">A delegate to the method used to create the view for the corresponding item.</param>
         /// <param name="clickCallback">An optional delegate to a method called when an item is clicked or tapped.</param>
+        /// <param name="getItemViewType">A delegate to the method used to decide the view type id.</param>
         /// <returns>The created <see cref="ObservableRecyclerAdapter{TItem, THolder}"/>.</returns>
         public static ObservableRecyclerAdapter<TItem, THolder> GetRecyclerAdapter<TItem, THolder>(
             this IList<TItem> list,
             Action<THolder, TItem, int> bindViewHolderDelegate,
             Func<ViewGroup, int, THolder> createViewHolderDelegate,
-            Action<int, View, int, View> clickCallback = null)
+            Action<int, View, int, View> clickCallback = null,
+            Func<int, int> getItemViewType = null)
             where THolder : RecyclerView.ViewHolder
         {
             return new ObservableRecyclerAdapter<TItem, THolder>
             {
                 DataSource = list,
                 BindViewHolderDelegate = bindViewHolderDelegate,
                 CreateViewHolderDelegate = createViewHolderDelegate,
+                GetItemViewTypeDelegate = getItemViewType,
                 ClickCallback = clickCallback
             };
         }
@@ -82,4 +85,4 @@ public static class ExtensionsAndroid2
             };
         }
     }
-}
+}

GalaSoft.MvvmLight/GalaSoft.MvvmLight.AndroidSupport/Helpers/ObservableRecyclerAdapter.cs

@@ -1,6 +1,6 @@
 // ****************************************************************************
 // <copyright file="ObservableRecyclerAdapter.cs" company="GalaSoft Laurent Bugnion">
-// Copyright © GalaSoft Laurent Bugnion 2009-2016
+// Copyright © GalaSoft Laurent Bugnion 2009-2016
 // </copyright>
 // ****************************************************************************
 // <author>Laurent Bugnion</author>
@@ -93,6 +93,16 @@ public int CellLayoutId
             set;
         }
 
+        /// <summary>
+        /// A delegate to a method taking an item's position and returning the view type.
+        /// If null, defult view type will always be 0.
+        /// </summary>
+        public Func<int, int> GetItemViewTypeDelegate
+        {
+            get;
+            set;
+        }
+
         /// <summary>
         /// The data source of this list adapter.
         /// </summary>
@@ -186,6 +196,23 @@ public override void OnBindViewHolder(RecyclerView.ViewHolder holder, int positi
 
             BindViewHolderDelegate((THolder)holder, _dataSource[position], position);
         }
+
+        /// <summary>
+        /// Gets the type of the item view and it will be passed to OnCreateViewHolder method
+        /// to handle multiple layout based on position.
+        /// </summary>
+        /// <returns>The item view type.</returns>
+        /// <param name="position">Position.</param>
+        public override int GetItemViewType(int position)
+        {
+            if (GetItemViewTypeDelegate == null)
+            {
+                return 0;
+            }
+
+            // No ViewHolderType specified --> Call the delegate
+            return GetItemViewTypeDelegate(position);
+        }
 
         /// <summary>
         /// Called when the View should be created.
@@ -335,4 +362,4 @@ private void RaiseSelectionChanged()
         /// </summary>
         public event EventHandler SelectionChanged;
     }
-}
+}