Added bindings for NestedScrollingEnabled override

See https://bugzilla.xamarin.com/show_bug.cgi?id=60052 for more info.

Basically, we’re having some issues at runtime on API < 21 with setNestedScrollingEnabled and isNestedScrollingEnabled since we compile the bindings themselves against > API 21 where View has these methods (they didn’t get introduced until API 21), so our generator does not emit override methods on RecyclerView for them, and when we lookup the jmethodID at runtime on API < 21, the methods don’t exist and we hit a missing method exception.  The fix here is to manually add the RecyclerView binding overrides.

Author: Redth

recyclerview-v7/source/Additions/Additions.cs

@@ -1,30 +1,61 @@
 using System;
+using Android.Runtime;
+
 namespace Android.Support.V7.Widget
-                 //.RecyclerView.RequestDisallowInterceptTouchEventEventArgs
 {
-	public partial class RecyclerView
-	{
-		public partial class InterceptTouchEventEventArgs
-		{
-			public RecyclerView RecyclerView {
-				get { return this.Rv;  }
-			}
-		}
-
-		public partial class RequestDisallowInterceptTouchEventEventArgs
-		{
-			public bool Disallow
-			{
-				get { return this.DisallowIntercept; }
-			}
-		}
-
-		public partial class TouchEventEventArgs
-		{
-			public RecyclerView RecyclerView
-			{
-				get { return this.Rv; }
-			}
-		}
-	}
+    public partial class RecyclerView
+    {
+        public partial class InterceptTouchEventEventArgs
+        {
+            public RecyclerView RecyclerView {
+                get { return this.Rv; }
+            }
+        }
+
+        public partial class RequestDisallowInterceptTouchEventEventArgs
+        {
+            public bool Disallow {
+                get { return this.DisallowIntercept; }
+            }
+        }
+
+        public partial class TouchEventEventArgs
+        {
+            public RecyclerView RecyclerView {
+                get { return this.Rv; }
+            }
+        }
+
+        private static IntPtr id_isNestedScrollingEnabled = IntPtr.Zero;
+        private static IntPtr id_setNestedScrollingEnabled = IntPtr.Zero;
+
+        public unsafe virtual bool NestedScrollingEnabled {
+            [Register("isNestedScrollingEnabled", "()Z", "GetIsNestedScrollingEnabledHandler")]
+            get {
+                if (id_isNestedScrollingEnabled == IntPtr.Zero) {
+                    id_isNestedScrollingEnabled = JNIEnv.GetMethodID(class_ref, "isNestedScrollingEnabled", "()Z");
+                }
+                if (base.GetType() == ThresholdType) {
+                    return JNIEnv.CallBooleanMethod(base.Handle, id_isNestedScrollingEnabled);
+                }
+                return JNIEnv.CallNonvirtualBooleanMethod(base.Handle, ThresholdClass, JNIEnv.GetMethodID(ThresholdClass, "isNestedScrollingEnabled", "()Z"));
+            }
+
+            [Register("setNestedScrollingEnabled", "(Z)V", "GetSetNestedScrollingEnabledHandler")]
+            set {
+                if (id_setNestedScrollingEnabled == IntPtr.Zero) {
+                    id_setNestedScrollingEnabled = JNIEnv.GetMethodID(class_ref, "setNestedScrollingEnabled", "(Z)V");
+                }
+                JValue* ptr = stackalloc JValue[1];
+                *ptr = new JValue(value);
+                if (base.GetType() == ThresholdType) {
+                    JNIEnv.CallVoidMethod(base.Handle, id_setNestedScrollingEnabled, ptr);
+                    return;
+                }
+                JNIEnv.CallNonvirtualVoidMethod(base.Handle, ThresholdClass, JNIEnv.GetMethodID(ThresholdClass, "setNestedScrollingEnabled", "(Z)V"), ptr);
+            }
+        }
+
+
+    }
 }