hybrid webview

src/Android/Android.csproj

@@ -43,6 +43,7 @@
   </PropertyGroup>
   <ItemGroup>
     <Reference Include="Mono.Android" />
+    <Reference Include="Mono.Android.Export" />
     <Reference Include="System" />
     <Reference Include="System.Core" />
     <Reference Include="System.Xml.Linq" />
@@ -87,6 +88,7 @@
     <Compile Include="Renderers\CustomEntryRenderer.cs" />
     <Compile Include="Renderers\CustomSearchBarRenderer.cs" />
     <Compile Include="Renderers\ExtendedListViewRenderer.cs" />
+    <Compile Include="Renderers\HybridWebViewRenderer.cs" />
     <Compile Include="SplashActivity.cs" />
     <Compile Include="Renderers\BoxedView\BoxedViewRecyclerAdapter.cs" />
     <Compile Include="Renderers\BoxedView\BoxedViewRenderer.cs" />

src/Android/Renderers/HybridWebViewRenderer.cs

@@ -0,0 +1,88 @@
+using System;
+using Bit.App.Controls;
+using Xamarin.Forms;
+using Xamarin.Forms.Platform.Android;
+using Android.Webkit;
+using AWebkit = Android.Webkit;
+using Java.Interop;
+using Android.Content;
+using Bit.Droid.Renderers;
+
+[assembly: ExportRenderer(typeof(HybridWebView), typeof(HybridWebViewRenderer))]
+namespace Bit.Droid.Renderers
+{
+    public class HybridWebViewRenderer : ViewRenderer<HybridWebView, AWebkit.WebView>
+    {
+        private const string JSFunction = "function invokeCSharpAction(data){jsBridge.invokeAction(data);}";
+
+        private readonly Context _context;
+
+        public HybridWebViewRenderer(Context context)
+            : base(context)
+        {
+            _context = context;
+        }
+
+        protected override void OnElementChanged(ElementChangedEventArgs<HybridWebView> e)
+        {
+            base.OnElementChanged(e);
+
+            if(Control == null)
+            {
+                var webView = new AWebkit.WebView(_context);
+                webView.Settings.JavaScriptEnabled = true;
+                webView.SetWebViewClient(new JSWebViewClient(string.Format("javascript: {0}", JSFunction)));
+                SetNativeControl(webView);
+            }
+            if(e.OldElement != null)
+            {
+                Control.RemoveJavascriptInterface("jsBridge");
+                var hybridWebView = e.OldElement as HybridWebView;
+                hybridWebView.Cleanup();
+            }
+            if(e.NewElement != null)
+            {
+                Control.AddJavascriptInterface(new JSBridge(this), "jsBridge");
+                Control.LoadUrl(Element.Uri);
+            }
+        }
+
+        public class JSBridge : Java.Lang.Object
+        {
+            private readonly WeakReference<HybridWebViewRenderer> _hybridWebViewRenderer;
+
+            public JSBridge(HybridWebViewRenderer hybridRenderer)
+            {
+                _hybridWebViewRenderer = new WeakReference<HybridWebViewRenderer>(hybridRenderer);
+            }
+
+            [JavascriptInterface]
+            [Export("invokeAction")]
+            public void InvokeAction(string data)
+            {
+                if(_hybridWebViewRenderer != null &&
+                    _hybridWebViewRenderer.TryGetTarget(out HybridWebViewRenderer hybridRenderer))
+                {
+                    hybridRenderer.Element.InvokeAction(data);
+                }
+            }
+        }
+
+        public class JSWebViewClient : WebViewClient
+        {
+            private readonly string _javascript;
+
+            public JSWebViewClient(string javascript)
+            {
+                _javascript = javascript;
+
+            }
+
+            public override void OnPageFinished(AWebkit.WebView view, string url)
+            {
+                base.OnPageFinished(view, url);
+                view.EvaluateJavascript(_javascript, null);
+            }
+        }
+    }
+}

src/App/Controls/HybridWebView.cs

@@ -0,0 +1,34 @@
+using System;
+using Xamarin.Forms;
+
+namespace Bit.App.Controls
+{
+    public class HybridWebView : View
+    {
+        private Action<string> _func;
+
+        public static readonly BindableProperty UriProperty = BindableProperty.Create(propertyName: nameof(Uri),
+            returnType: typeof(string), declaringType: typeof(HybridWebView), defaultValue: default(string));
+
+        public string Uri
+        {
+            get { return (string)GetValue(UriProperty); }
+            set { SetValue(UriProperty, value); }
+        }
+
+        public void RegisterAction(Action<string> callback)
+        {
+            _func = callback;
+        }
+
+        public void Cleanup()
+        {
+            _func = null;
+        }
+
+        public void InvokeAction(string data)
+        {
+            _func?.Invoke(data);
+        }
+    }
+}

src/iOS/Renderers/HybridWebViewRenderer.cs

@@ -0,0 +1,51 @@
+using Foundation;
+using WebKit;
+using Xamarin.Forms;
+using Xamarin.Forms.Platform.iOS;
+using Bit.App.Controls;
+using Bit.iOS.Renderers;
+
+[assembly: ExportRenderer(typeof(HybridWebView), typeof(HybridWebViewRenderer))]
+namespace Bit.iOS.Renderers
+{
+    public class HybridWebViewRenderer : ViewRenderer<HybridWebView, WKWebView>, IWKScriptMessageHandler
+    {
+        private const string JSFunction =
+            "function invokeCSharpAction(data){window.webkit.messageHandlers.invokeAction.postMessage(data);}";
+
+        private WKUserContentController _userController;
+
+        protected override void OnElementChanged(ElementChangedEventArgs<HybridWebView> e)
+        {
+            base.OnElementChanged(e);
+
+            if(Control == null)
+            {
+                _userController = new WKUserContentController();
+                var script = new WKUserScript(new NSString(JSFunction), WKUserScriptInjectionTime.AtDocumentEnd, false);
+                _userController.AddUserScript(script);
+                _userController.AddScriptMessageHandler(this, "invokeAction");
+
+                var config = new WKWebViewConfiguration { UserContentController = _userController };
+                var webView = new WKWebView(Frame, config);
+                SetNativeControl(webView);
+            }
+            if(e.OldElement != null)
+            {
+                _userController.RemoveAllUserScripts();
+                _userController.RemoveScriptMessageHandler("invokeAction");
+                var hybridWebView = e.OldElement as HybridWebView;
+                hybridWebView.Cleanup();
+            }
+            if(e.NewElement != null)
+            {
+                Control.LoadRequest(new NSUrlRequest(new NSUrl(Element.Uri)));
+            }
+        }
+
+        public void DidReceiveScriptMessage(WKUserContentController userContentController, WKScriptMessage message)
+        {
+            Element.InvokeAction(message.Body.ToString());
+        }
+    }
+}

src/iOS/iOS.csproj

@@ -92,6 +92,7 @@
   <ItemGroup>
     <Compile Include="Main.cs" />
     <Compile Include="AppDelegate.cs" />
+    <Compile Include="Renderers\HybridWebViewRenderer.cs" />
     <Compile Include="Services\DeviceActionService.cs" />
     <None Include="Entitlements.plist" />
     <None Include="Info.plist" />