[Android] Null reference exception fix (#252)

* Added null checks

* Replaced spaces with tabs

diff --git a/Xamarin.Forms.Platform.Android/Renderers/ListViewRenderer.cs b/Xamarin.Forms.Platform.Android/Renderers/ListViewRenderer.cs
index 08bc2f5..4175810 100644 (file)
--- a/Xamarin.Forms.Platform.Android/Renderers/ListViewRenderer.cs
+++ b/Xamarin.Forms.Platform.Android/Renderers/ListViewRenderer.cs
@@ -249,7 +249,8 @@ namespace Xamarin.Forms.Platform.Android
                        var footer = (VisualElement)Controller.FooterElement;
                        if (_footerRenderer != null && (footer == null || Registrar.Registered.GetHandlerType(footer.GetType()) != _footerRenderer.GetType()))
                        {
-                               _footerView.Child = null;
+                               if (_footerView != null)
+                                       _footerView.Child = null;
                                _footerRenderer.Dispose();
                                _footerRenderer = null;
                        }
@@ -262,7 +263,8 @@ namespace Xamarin.Forms.Platform.Android
                        else
                        {
                                _footerRenderer = Platform.CreateRenderer(footer);
-                               _footerView.Child = _footerRenderer;
+                               if (_footerView != null)
+                                       _footerView.Child = _footerRenderer;
                        }
 
                        Platform.SetRenderer(footer, _footerRenderer);
@@ -273,7 +275,8 @@ namespace Xamarin.Forms.Platform.Android
                        var header = (VisualElement)Controller.HeaderElement;
                        if (_headerRenderer != null && (header == null || Registrar.Registered.GetHandlerType(header.GetType()) != _headerRenderer.GetType()))
                        {
-                               _headerView.Child = null;
+                               if (_headerView != null)
+                                       _headerView.Child = null;
                                _headerRenderer.Dispose();
                                _headerRenderer = null;
                        }
@@ -286,7 +289,8 @@ namespace Xamarin.Forms.Platform.Android
                        else
                        {
                                _headerRenderer = Platform.CreateRenderer(header);
-                               _headerView.Child = _headerRenderer;
+                               if (_headerView != null)
+                                       _headerView.Child = _headerRenderer;
                        }
 
                        Platform.SetRenderer(header, _headerRenderer);
@@ -294,12 +298,14 @@ namespace Xamarin.Forms.Platform.Android
 
                void UpdateIsRefreshing()
                {
-                       _refresh.Refreshing = Element.IsRefreshing;
+                       if (_refresh != null)
+                               _refresh.Refreshing = Element.IsRefreshing;
                }
 
                void UpdateIsSwipeToRefreshEnabled()
                {
-                       _refresh.Enabled = Element.IsPullToRefreshEnabled && (Element as IListViewController).RefreshAllowed;
+                       if (_refresh != null)
+                               _refresh.Enabled = Element.IsPullToRefreshEnabled && (Element as IListViewController).RefreshAllowed;
                }
 
                internal class Container : ViewGroup
@@ -357,4 +363,4 @@ namespace Xamarin.Forms.Platform.Android
                        }
                }
        }
-}
\ No newline at end of file
+}