custom content page renderer for left nav items

src/iOS/Renderers/CustomContentPageRenderer.cs

@@ -0,0 +1,56 @@
+using System.Collections.Generic;
+using System.Linq;
+using System.Reflection;
+using Bit.iOS.Renderers;
+using UIKit;
+using Xamarin.Forms;
+using Xamarin.Forms.Platform.iOS;
+
+[assembly: ExportRenderer(typeof(ContentPage), typeof(CustomContentPageRenderer))]
+namespace Bit.iOS.Renderers
+{
+    public class CustomContentPageRenderer : PageRenderer
+    {
+        public override void ViewWillAppear(bool animated)
+        {
+            base.ViewWillAppear(animated);
+            if(!(Element is ContentPage contentPage) || NavigationController == null)
+            {
+                return;
+            }
+
+            var navigationItem = NavigationController.TopViewController.NavigationItem;
+            var leftNativeButtons = (navigationItem.LeftBarButtonItems ?? new UIBarButtonItem[] { }).ToList();
+            var rightNativeButtons = (navigationItem.RightBarButtonItems ?? new UIBarButtonItem[] { }).ToList();
+            var newLeftButtons = new List<UIBarButtonItem>();
+            var newRightButtons = new List<UIBarButtonItem>();
+            foreach(var nativeItem in rightNativeButtons)
+            {
+                // Use reflection to get Xamarin private field "_item"
+                var field = nativeItem.GetType().GetField("_item", BindingFlags.NonPublic | BindingFlags.Instance);
+                if(field == null)
+                {
+                    return;
+                }
+                if(!(field.GetValue(nativeItem) is ToolbarItem info))
+                {
+                    return;
+                }
+                if(info.Priority < 0)
+                {
+                    newLeftButtons.Add(nativeItem);
+                }
+                else
+                {
+                    newRightButtons.Add(nativeItem);
+                }
+            }
+            foreach(var nativeItem in leftNativeButtons)
+            {
+                newLeftButtons.Add(nativeItem);
+            }
+            navigationItem.RightBarButtonItems = newRightButtons.ToArray();
+            navigationItem.LeftBarButtonItems = newLeftButtons.ToArray();
+        }
+    }
+}

src/iOS/iOS.csproj

@@ -112,6 +112,7 @@
     <Compile Include="Main.cs" />
     <Compile Include="AppDelegate.cs" />
     <Compile Include="Migration\KeyChainStorageService.cs" />
+    <Compile Include="Renderers\CustomContentPageRenderer.cs" />
     <Compile Include="Renderers\HybridWebViewRenderer.cs" />
     <Compile Include="Services\DeviceActionService.cs" />
     <Compile Include="Services\iOSPushNotificationHandler.cs" />