Merge pull request #523 from rinlv/master

Listen javascript function from flutter

android/src/main/AndroidManifest.xml

@@ -1,6 +1,7 @@
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
           xmlns:tools="http://schemas.android.com/tools"
           package="com.flutter_webview_plugin">
+
     <application>
         <provider
             android:name="androidx.core.content.FileProvider"

android/src/main/java/com/flutter_webview_plugin/FlutterWebviewPlugin.java

@@ -11,6 +11,8 @@ import android.webkit.CookieManager;
 import android.webkit.ValueCallback;
 import android.os.Build;
 
+import java.util.ArrayList;
+import java.util.List;
 import java.util.Map;
 
 import io.flutter.plugin.common.MethodCall;
@@ -27,10 +29,11 @@ public class FlutterWebviewPlugin implements MethodCallHandler, PluginRegistry.A
     private Context context;
     static MethodChannel channel;
     private static final String CHANNEL_NAME = "flutter_webview_plugin";
+    private static final String JS_CHANNEL_NAMES_FIELD = "javascriptChannelNames";
 
     public static void registerWith(PluginRegistry.Registrar registrar) {
         channel = new MethodChannel(registrar.messenger(), CHANNEL_NAME);
-        final FlutterWebviewPlugin instance = new FlutterWebviewPlugin(registrar.activity(),registrar.activeContext());
+        final FlutterWebviewPlugin instance = new FlutterWebviewPlugin(registrar.activity(), registrar.activeContext());
         registrar.addActivityResultListener(instance);
         channel.setMethodCallHandler(instance);
     }
@@ -107,7 +110,12 @@ public class FlutterWebviewPlugin implements MethodCallHandler, PluginRegistry.A
         boolean debuggingEnabled = call.argument("debuggingEnabled");
 
         if (webViewManager == null || webViewManager.closed == true) {
-            webViewManager = new WebviewManager(activity, context);
+            Map<String, Object> arguments = (Map<String, Object>) call.arguments;
+            List<String> channelNames = new ArrayList();
+            if (arguments.containsKey(JS_CHANNEL_NAMES_FIELD)) {
+                channelNames = (List<String>) arguments.get(JS_CHANNEL_NAMES_FIELD);
+            }
+            webViewManager = new WebviewManager(activity, context, channelNames);
         }
 
         FrameLayout.LayoutParams params = buildLayoutParams(call);

android/src/main/java/com/flutter_webview_plugin/JavaScriptChannel.java

@@ -0,0 +1,60 @@
+// Copyright 2019 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+package com.flutter_webview_plugin;
+
+import android.os.Handler;
+import android.os.Looper;
+import android.webkit.JavascriptInterface;
+
+import java.util.HashMap;
+
+import io.flutter.plugin.common.MethodChannel;
+
+/**
+ * Added as a JavaScript interface to the WebView for any JavaScript channel that the Dart code sets
+ * up.
+ *
+ * <p>Exposes a single method named `postMessage` to JavaScript, which sends a message over a method
+ * channel to the Dart code.
+ */
+class JavaScriptChannel {
+  private final MethodChannel methodChannel;
+  private final String javaScriptChannelName;
+  private final Handler platformThreadHandler;
+
+  /**
+   * @param methodChannel the Flutter WebView method channel to which JS messages are sent
+   * @param javaScriptChannelName the name of the JavaScript channel, this is sent over the method
+   *     channel with each message to let the Dart code know which JavaScript channel the message
+   *     was sent through
+   */
+  JavaScriptChannel(
+      MethodChannel methodChannel, String javaScriptChannelName, Handler platformThreadHandler) {
+    this.methodChannel = methodChannel;
+    this.javaScriptChannelName = javaScriptChannelName;
+    this.platformThreadHandler = platformThreadHandler;
+  }
+
+  // Suppressing unused warning as this is invoked from JavaScript.
+  @SuppressWarnings("unused")
+  @JavascriptInterface
+  public void postMessage(final String message) {
+    Runnable postMessageRunnable =
+        new Runnable() {
+          @Override
+          public void run() {
+            HashMap<String, String> arguments = new HashMap<>();
+            arguments.put("channel", javaScriptChannelName);
+            arguments.put("message", message);
+            methodChannel.invokeMethod("javascriptChannelMessage", arguments);
+          }
+        };
+    if (platformThreadHandler.getLooper() == Looper.myLooper()) {
+      postMessageRunnable.run();
+    } else {
+      platformThreadHandler.post(postMessageRunnable);
+    }
+  }
+}

android/src/main/java/com/flutter_webview_plugin/WebviewManager.java

@@ -6,6 +6,7 @@ import android.annotation.TargetApi;
 import android.app.Activity;
 import android.content.Context;
 import android.os.Build;
+import android.os.Handler;
 import android.view.KeyEvent;
 import android.view.View;
 import android.view.ViewGroup;
@@ -17,7 +18,9 @@ import android.webkit.WebSettings;
 import android.webkit.WebView;
 import android.widget.FrameLayout;
 import android.provider.MediaStore;
+
 import androidx.core.content.FileProvider;
+
 import android.database.Cursor;
 import android.provider.OpenableColumns;
 
@@ -43,7 +46,7 @@ class WebviewManager {
 
     private ValueCallback<Uri> mUploadMessage;
     private ValueCallback<Uri[]> mUploadMessageArray;
-    private final static int FILECHOOSER_RESULTCODE=1;
+    private final static int FILECHOOSER_RESULTCODE = 1;
     private Uri fileUri;
     private Uri videoUri;
 
@@ -56,29 +59,29 @@ class WebviewManager {
 
     @TargetApi(7)
     class ResultHandler {
-        public boolean handleResult(int requestCode, int resultCode, Intent intent){
+        public boolean handleResult(int requestCode, int resultCode, Intent intent) {
             boolean handled = false;
-            if(Build.VERSION.SDK_INT >= 21){
-                if(requestCode == FILECHOOSER_RESULTCODE){
+            if (Build.VERSION.SDK_INT >= 21) {
+                if (requestCode == FILECHOOSER_RESULTCODE) {
                     Uri[] results = null;
                     if (resultCode == Activity.RESULT_OK) {
                         if (fileUri != null && getFileSize(fileUri) > 0) {
-                            results = new Uri[] { fileUri };
+                            results = new Uri[]{fileUri};
                         } else if (videoUri != null && getFileSize(videoUri) > 0) {
-                            results = new Uri[] { videoUri };
+                            results = new Uri[]{videoUri};
                         } else if (intent != null) {
                             results = getSelectedFiles(intent);
                         }
                     }
-                    if(mUploadMessageArray != null){
+                    if (mUploadMessageArray != null) {
                         mUploadMessageArray.onReceiveValue(results);
                         mUploadMessageArray = null;
                     }
                     handled = true;
                 }
-            }else {
+            } else {
                 if (requestCode == FILECHOOSER_RESULTCODE) {
-                	Uri result = null;
+                    Uri result = null;
                     if (resultCode == RESULT_OK && intent != null) {
                         result = intent.getData();
                     }
@@ -97,8 +100,8 @@ class WebviewManager {
         // we have one files selected
         if (data.getData() != null) {
             String dataString = data.getDataString();
-            if(dataString != null){
-                return new Uri[]{ Uri.parse(dataString) };
+            if (dataString != null) {
+                return new Uri[]{Uri.parse(dataString)};
             }
         }
         // we have multiple files selected
@@ -113,6 +116,7 @@ class WebviewManager {
         return null;
     }
 
+    private final Handler platformThreadHandler;
     boolean closed = false;
     WebView webView;
     Activity activity;
@@ -120,11 +124,12 @@ class WebviewManager {
     ResultHandler resultHandler;
     Context context;
 
-    WebviewManager(final Activity activity, final Context context) {
+    WebviewManager(final Activity activity, final Context context, final List<String> channelNames) {
         this.webView = new ObservableWebView(activity);
         this.activity = activity;
         this.context = context;
         this.resultHandler = new ResultHandler();
+        this.platformThreadHandler = new Handler(context.getMainLooper());
         webViewClient = new BrowserClient();
         webView.setOnKeyListener(new View.OnKeyListener() {
             @Override
@@ -145,20 +150,19 @@ class WebviewManager {
             }
         });
 
-        ((ObservableWebView) webView).setOnScrollChangedCallback(new ObservableWebView.OnScrollChangedCallback(){
-            public void onScroll(int x, int y, int oldx, int oldy){
+        ((ObservableWebView) webView).setOnScrollChangedCallback(new ObservableWebView.OnScrollChangedCallback() {
+            public void onScroll(int x, int y, int oldx, int oldy) {
                 Map<String, Object> yDirection = new HashMap<>();
-                yDirection.put("yDirection", (double)y);
+                yDirection.put("yDirection", (double) y);
                 FlutterWebviewPlugin.channel.invokeMethod("onScrollYChanged", yDirection);
                 Map<String, Object> xDirection = new HashMap<>();
-                xDirection.put("xDirection", (double)x);
+                xDirection.put("xDirection", (double) x);
                 FlutterWebviewPlugin.channel.invokeMethod("onScrollXChanged", xDirection);
             }
         });
 
         webView.setWebViewClient(webViewClient);
-        webView.setWebChromeClient(new WebChromeClient()
-        {
+        webView.setWebChromeClient(new WebChromeClient() {
             //The undocumented magic method override
             //Eclipse will swear at you if you try to put @Override here
             // For Android 3.0+
@@ -168,36 +172,36 @@ class WebviewManager {
                 Intent i = new Intent(Intent.ACTION_GET_CONTENT);
                 i.addCategory(Intent.CATEGORY_OPENABLE);
                 i.setType("image/*");
-                activity.startActivityForResult(Intent.createChooser(i,"File Chooser"), FILECHOOSER_RESULTCODE);
+                activity.startActivityForResult(Intent.createChooser(i, "File Chooser"), FILECHOOSER_RESULTCODE);
 
             }
 
             // For Android 3.0+
-            public void openFileChooser( ValueCallback uploadMsg, String acceptType ) {
+            public void openFileChooser(ValueCallback uploadMsg, String acceptType) {
                 mUploadMessage = uploadMsg;
                 Intent i = new Intent(Intent.ACTION_GET_CONTENT);
                 i.addCategory(Intent.CATEGORY_OPENABLE);
                 i.setType("*/*");
-               activity.startActivityForResult(
+                activity.startActivityForResult(
                         Intent.createChooser(i, "File Browser"),
                         FILECHOOSER_RESULTCODE);
             }
 
             //For Android 4.1
-            public void openFileChooser(ValueCallback<Uri> uploadMsg, String acceptType, String capture){
+            public void openFileChooser(ValueCallback<Uri> uploadMsg, String acceptType, String capture) {
                 mUploadMessage = uploadMsg;
                 Intent i = new Intent(Intent.ACTION_GET_CONTENT);
                 i.addCategory(Intent.CATEGORY_OPENABLE);
                 i.setType("image/*");
-                activity.startActivityForResult( Intent.createChooser( i, "File Chooser" ), FILECHOOSER_RESULTCODE );
+                activity.startActivityForResult(Intent.createChooser(i, "File Chooser"), FILECHOOSER_RESULTCODE);
 
             }
 
             //For Android 5.0+
             public boolean onShowFileChooser(
                     WebView webView, ValueCallback<Uri[]> filePathCallback,
-                    FileChooserParams fileChooserParams){
-                if(mUploadMessageArray != null){
+                    FileChooserParams fileChooserParams) {
+                if (mUploadMessageArray != null) {
                     mUploadMessageArray.onReceiveValue(null);
                 }
                 mUploadMessageArray = filePathCallback;
@@ -248,6 +252,7 @@ class WebviewManager {
                 callback.invoke(origin, true, false);
             }
         });
+        registerJavaScriptChannelNames(channelNames);
     }
 
     private Uri getOutputFilename(String intentType) {
@@ -334,6 +339,13 @@ class WebviewManager {
         webView.clearFormData();
     }
 
+    private void registerJavaScriptChannelNames(List<String> channelNames) {
+        for (String channelName : channelNames) {
+            webView.addJavascriptInterface(
+                    new JavaScriptChannel(FlutterWebviewPlugin.channel, channelName, platformThreadHandler), channelName);
+        }
+    }
+
     void openUrl(
             boolean withJavascript,
             boolean clearCache,
@@ -371,7 +383,7 @@ class WebviewManager {
         webView.getSettings().setAllowUniversalAccessFromFileURLs(allowFileURLs);
 
         webView.getSettings().setUseWideViewPort(useWideViewPort);
-        
+
         // Handle debugging
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {
             webView.setWebContentsDebuggingEnabled(debuggingEnabled);
@@ -403,7 +415,7 @@ class WebviewManager {
             webView.getSettings().setUserAgentString(userAgent);
         }
 
-        if(!scrollBar){
+        if (!scrollBar) {
             webView.setVerticalScrollBarEnabled(false);
         }
 
@@ -451,25 +463,28 @@ class WebviewManager {
             }
         });
     }
+
     /**
-    * Reloads the Webview.
-    */
+     * Reloads the Webview.
+     */
     void reload(MethodCall call, MethodChannel.Result result) {
         if (webView != null) {
             webView.reload();
         }
     }
+
     /**
-    * Navigates back on the Webview.
-    */
+     * Navigates back on the Webview.
+     */
     void back(MethodCall call, MethodChannel.Result result) {
         if (webView != null && webView.canGoBack()) {
             webView.goBack();
         }
     }
+
     /**
-    * Navigates forward on the Webview.
-    */
+     * Navigates forward on the Webview.
+     */
     void forward(MethodCall call, MethodChannel.Result result) {
         if (webView != null && webView.canGoForward()) {
             webView.goForward();
@@ -479,31 +494,35 @@ class WebviewManager {
     void resize(FrameLayout.LayoutParams params) {
         webView.setLayoutParams(params);
     }
+
     /**
-    * Checks if going back on the Webview is possible.
-    */
+     * Checks if going back on the Webview is possible.
+     */
     boolean canGoBack() {
         return webView.canGoBack();
     }
+
     /**
-    * Checks if going forward on the Webview is possible.
-    */
+     * Checks if going forward on the Webview is possible.
+     */
     boolean canGoForward() {
         return webView.canGoForward();
     }
+
     void hide(MethodCall call, MethodChannel.Result result) {
         if (webView != null) {
             webView.setVisibility(View.GONE);
         }
     }
+
     void show(MethodCall call, MethodChannel.Result result) {
         if (webView != null) {
             webView.setVisibility(View.VISIBLE);
         }
     }
 
-    void stopLoading(MethodCall call, MethodChannel.Result result){
-        if (webView != null){
+    void stopLoading(MethodCall call, MethodChannel.Result result) {
+        if (webView != null) {
             webView.stopLoading();
         }
     }

example/android/build.gradle

@@ -32,6 +32,7 @@ task clean(type: Delete) {
     delete rootProject.buildDir
 }
 
-task wrapper(type: Wrapper) {
-    gradleVersion = '4.10.2'
+wrapper {
+    gradleVersion = '4.4'
+    distributionUrl = distributionUrl.replace("bin", "all")
 }

example/ios/Runner.xcodeproj/project.pbxproj

@@ -7,11 +7,13 @@
 	objects = {
 
 /* Begin PBXBuildFile section */
+		2D5378261FAA1A9400D5DBA9 /* flutter_assets in Resources */ = {isa = PBXBuildFile; fileRef = 2D5378251FAA1A9400D5DBA9 /* flutter_assets */; };
 		3B3967161E833CAA004F5970 /* AppFrameworkInfo.plist in Resources */ = {isa = PBXBuildFile; fileRef = 3B3967151E833CAA004F5970 /* AppFrameworkInfo.plist */; };
 		3B80C3941E831B6300D905FE /* App.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 3B80C3931E831B6300D905FE /* App.framework */; };
 		3B80C3951E831B6300D905FE /* App.framework in Embed Frameworks */ = {isa = PBXBuildFile; fileRef = 3B80C3931E831B6300D905FE /* App.framework */; settings = {ATTRIBUTES = (CodeSignOnCopy, RemoveHeadersOnCopy, ); }; };
 		945777F11EF64758001C8557 /* GeneratedPluginRegistrant.m in Sources */ = {isa = PBXBuildFile; fileRef = 945777F01EF64758001C8557 /* GeneratedPluginRegistrant.m */; };
 		9705A1C61CF904A100538489 /* Flutter.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 9740EEBA1CF902C7004384FC /* Flutter.framework */; };
+		9705A1C71CF904A300538489 /* Flutter.framework in Embed Frameworks */ = {isa = PBXBuildFile; fileRef = 9740EEBA1CF902C7004384FC /* Flutter.framework */; settings = {ATTRIBUTES = (CodeSignOnCopy, RemoveHeadersOnCopy, ); }; };
 		9740EEB41CF90195004384FC /* Debug.xcconfig in Resources */ = {isa = PBXBuildFile; fileRef = 9740EEB21CF90195004384FC /* Debug.xcconfig */; };
 		9740EEB51CF90195004384FC /* Generated.xcconfig in Resources */ = {isa = PBXBuildFile; fileRef = 9740EEB31CF90195004384FC /* Generated.xcconfig */; };
 		978B8F6F1D3862AE00F588F7 /* AppDelegate.m in Sources */ = {isa = PBXBuildFile; fileRef = 7AFFD8EE1D35381100E5BB4D /* AppDelegate.m */; };
@@ -30,6 +32,7 @@
 			dstSubfolderSpec = 10;
 			files = (
 				3B80C3951E831B6300D905FE /* App.framework in Embed Frameworks */,
+				9705A1C71CF904A300538489 /* Flutter.framework in Embed Frameworks */,
 			);
 			name = "Embed Frameworks";
 			runOnlyForDeploymentPostprocessing = 0;
@@ -37,7 +40,7 @@
 /* End PBXCopyFilesBuildPhase section */
 
 /* Begin PBXFileReference section */
-		04A45F9D7EB8F4F508843D7B /* Pods-Runner.release.xcconfig */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = text.xcconfig; name = "Pods-Runner.release.xcconfig"; path = "Pods/Target Support Files/Pods-Runner/Pods-Runner.release.xcconfig"; sourceTree = "<group>"; };
+		2D5378251FAA1A9400D5DBA9 /* flutter_assets */ = {isa = PBXFileReference; lastKnownFileType = folder; name = flutter_assets; path = Flutter/flutter_assets; sourceTree = SOURCE_ROOT; };
 		3B3967151E833CAA004F5970 /* AppFrameworkInfo.plist */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text.plist.xml; name = AppFrameworkInfo.plist; path = Flutter/AppFrameworkInfo.plist; sourceTree = "<group>"; };
 		3B80C3931E831B6300D905FE /* App.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = App.framework; path = Flutter/App.framework; sourceTree = "<group>"; };
 		7AFA3C8E1D35360C0083082E /* Release.xcconfig */ = {isa = PBXFileReference; lastKnownFileType = text.xcconfig; name = Release.xcconfig; path = Flutter/Release.xcconfig; sourceTree = "<group>"; };
@@ -55,7 +58,6 @@
 		97C147001CF9000F007C117D /* Base */ = {isa = PBXFileReference; lastKnownFileType = file.storyboard; name = Base; path = Base.lproj/LaunchScreen.storyboard; sourceTree = "<group>"; };
 		97C147021CF9000F007C117D /* Info.plist */ = {isa = PBXFileReference; lastKnownFileType = text.plist.xml; path = Info.plist; sourceTree = "<group>"; };
 		9A3CDD044DB4E60255722586 /* Pods_Runner.framework */ = {isa = PBXFileReference; explicitFileType = wrapper.framework; includeInIndex = 0; path = Pods_Runner.framework; sourceTree = BUILT_PRODUCTS_DIR; };
-		DB142FA5095D20B047B504E1 /* Pods-Runner.debug.xcconfig */ = {isa = PBXFileReference; includeInIndex = 1; lastKnownFileType = text.xcconfig; name = "Pods-Runner.debug.xcconfig"; path = "Pods/Target Support Files/Pods-Runner/Pods-Runner.debug.xcconfig"; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
 /* Begin PBXFrameworksBuildPhase section */
@@ -75,8 +77,6 @@
 		840012C8B5EDBCF56B0E4AC1 /* Pods */ = {
 			isa = PBXGroup;
 			children = (
-				DB142FA5095D20B047B504E1 /* Pods-Runner.debug.xcconfig */,
-				04A45F9D7EB8F4F508843D7B /* Pods-Runner.release.xcconfig */,
 			);
 			name = Pods;
 			sourceTree = "<group>";
@@ -86,6 +86,7 @@
 			children = (
 				3B80C3931E831B6300D905FE /* App.framework */,
 				3B3967151E833CAA004F5970 /* AppFrameworkInfo.plist */,
+				2D5378251FAA1A9400D5DBA9 /* flutter_assets */,
 				9740EEBA1CF902C7004384FC /* Flutter.framework */,
 				9740EEB21CF90195004384FC /* Debug.xcconfig */,
 				7AFA3C8E1D35360C0083082E /* Release.xcconfig */,
@@ -181,7 +182,6 @@
 				TargetAttributes = {
 					97C146ED1CF9000F007C117D = {
 						CreatedOnToolsVersion = 7.3.1;
-						DevelopmentTeam = 2RC73M8QLE;
 					};
 				};
 			};
@@ -190,7 +190,6 @@
 			developmentRegion = English;
 			hasScannedForEncodings = 0;
 			knownRegions = (
-				English,
 				en,
 				Base,
 			);
@@ -212,6 +211,7 @@
 				97C147011CF9000F007C117D /* LaunchScreen.storyboard in Resources */,
 				9740EEB51CF90195004384FC /* Generated.xcconfig in Resources */,
 				3B3967161E833CAA004F5970 /* AppFrameworkInfo.plist in Resources */,
+				2D5378261FAA1A9400D5DBA9 /* flutter_assets in Resources */,
 				9740EEB41CF90195004384FC /* Debug.xcconfig in Resources */,
 				97C146FE1CF9000F007C117D /* Assets.xcassets in Resources */,
 				97C146FC1CF9000F007C117D /* Main.storyboard in Resources */,
@@ -241,7 +241,7 @@
 			files = (
 			);
 			inputPaths = (
-				"${PODS_ROOT}/Target Support Files/Pods-Runner/Pods-Runner-frameworks.sh",
+				"${SRCROOT}/Pods/Target Support Files/Pods-Runner/Pods-Runner-frameworks.sh",
 				"${PODS_ROOT}/../../../../../flutter/bin/cache/artifacts/engine/ios/Flutter.framework",
 				"${BUILT_PRODUCTS_DIR}/flutter_webview_plugin/flutter_webview_plugin.framework",
 			);
@@ -252,7 +252,7 @@
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 			shellPath = /bin/sh;
-			shellScript = "\"${PODS_ROOT}/Target Support Files/Pods-Runner/Pods-Runner-frameworks.sh\"\n";
+			shellScript = "\"${SRCROOT}/Pods/Target Support Files/Pods-Runner/Pods-Runner-frameworks.sh\"\n";
 			showEnvVarsInLog = 0;
 		};
 		9740EEB61CF901F6004384FC /* Run Script */ = {
@@ -418,7 +418,6 @@
 			buildSettings = {
 				ARCHS = arm64;
 				ASSETCATALOG_COMPILER_APPICON_NAME = AppIcon;
-				DEVELOPMENT_TEAM = 2RC73M8QLE;
 				ENABLE_BITCODE = NO;
 				FRAMEWORK_SEARCH_PATHS = (
 					"$(inherited)",
@@ -441,7 +440,6 @@
 			buildSettings = {
 				ARCHS = arm64;
 				ASSETCATALOG_COMPILER_APPICON_NAME = AppIcon;
-				DEVELOPMENT_TEAM = 2RC73M8QLE;
 				ENABLE_BITCODE = NO;
 				FRAMEWORK_SEARCH_PATHS = (
 					"$(inherited)",

example/ios/Runner.xcworkspace/xcshareddata/IDEWorkspaceChecks.plist

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>IDEDidComputeMac32BitWarning</key>
+	<true/>
+</dict>
+</plist>

example/ios/Runner/Info.plist

@@ -26,10 +26,6 @@
 	<string>LaunchScreen</string>
 	<key>UIMainStoryboardFile</key>
 	<string>Main</string>
-	<key>UIRequiredDeviceCapabilities</key>
-	<array>
-		<string>arm64</string>
-	</array>
 	<key>UISupportedInterfaceOrientations</key>
 	<array>
 		<string>UIInterfaceOrientationPortrait</string>

example/lib/main.dart

@@ -9,6 +9,15 @@ const kAndroidUserAgent =
 
 String selectedUrl = 'https://flutter.io';
 
+// ignore: prefer_collection_literals
+final Set<JavascriptChannel> jsChannels = [
+  JavascriptChannel(
+      name: 'Print',
+      onMessageReceived: (JavascriptMessage message) {
+        print(message.message);
+      }),
+].toSet();
+
 void main() => runApp(MyApp());
 
 class MyApp extends StatelessWidget {
@@ -26,6 +35,7 @@ class MyApp extends StatelessWidget {
         '/widget': (_) {
           return WebviewScaffold(
             url: selectedUrl,
+            javascriptChannels: jsChannels,
             appBar: AppBar(
               title: const Text('Widget WebView'),
             ),
@@ -121,7 +131,8 @@ class _MyHomePageState extends State<MyHomePage> {
     _onDestroy = flutterWebViewPlugin.onDestroy.listen((_) {
       if (mounted) {
         // Actions like show a info toast.
-        _scaffoldKey.currentState.showSnackBar(const SnackBar(content: const Text('Webview Destroyed')));
+        _scaffoldKey.currentState.showSnackBar(
+            const SnackBar(content: const Text('Webview Destroyed')));
       }
     });
 
@@ -134,15 +145,17 @@ class _MyHomePageState extends State<MyHomePage> {
       }
     });
 
-    _onProgressChanged = flutterWebViewPlugin.onProgressChanged.listen((double progress) {
+    _onProgressChanged =
+        flutterWebViewPlugin.onProgressChanged.listen((double progress) {
       if (mounted) {
         setState(() {
-          _history.add("onProgressChanged: $progress");
+          _history.add('onProgressChanged: $progress');
         });
       }
     });
-    
-    _onScrollYChanged = flutterWebViewPlugin.onScrollYChanged.listen((double y) {
+
+    _onScrollYChanged =
+        flutterWebViewPlugin.onScrollYChanged.listen((double y) {
       if (mounted) {
         setState(() {
           _history.add('Scroll in Y Direction: $y');
@@ -150,7 +163,8 @@ class _MyHomePageState extends State<MyHomePage> {
       }
     });
 
-    _onScrollXChanged = flutterWebViewPlugin.onScrollXChanged.listen((double x) {
+    _onScrollXChanged =
+        flutterWebViewPlugin.onScrollXChanged.listen((double x) {
       if (mounted) {
         setState(() {
           _history.add('Scroll in X Direction: $x');
@@ -158,7 +172,8 @@ class _MyHomePageState extends State<MyHomePage> {
       }
     });
 
-    _onStateChanged = flutterWebViewPlugin.onStateChanged.listen((WebViewStateChanged state) {
+    _onStateChanged =
+        flutterWebViewPlugin.onStateChanged.listen((WebViewStateChanged state) {
       if (mounted) {
         setState(() {
           _history.add('onStateChanged: ${state.type} ${state.url}');
@@ -166,7 +181,8 @@ class _MyHomePageState extends State<MyHomePage> {
       }
     });
 
-    _onHttpError = flutterWebViewPlugin.onHttpError.listen((WebViewHttpError error) {
+    _onHttpError =
+        flutterWebViewPlugin.onHttpError.listen((WebViewHttpError error) {
       if (mounted) {
         setState(() {
           _history.add('onHttpError: ${error.code} ${error.url}');
@@ -210,9 +226,11 @@ class _MyHomePageState extends State<MyHomePage> {
               onPressed: () {
                 flutterWebViewPlugin.launch(
                   selectedUrl,
-                  rect: Rect.fromLTWH(0.0, 0.0, MediaQuery.of(context).size.width, 300.0),
+                  rect: Rect.fromLTWH(
+                      0.0, 0.0, MediaQuery.of(context).size.width, 300.0),
                   userAgent: kAndroidUserAgent,
-                  invalidUrlRegex: r'^(https).+(twitter)', // prevent redirecting to twitter when user click on its icon in flutter website
+                  invalidUrlRegex:
+                      r'^(https).+(twitter)', // prevent redirecting to twitter when user click on its icon in flutter website
                 );
               },
               child: const Text('Open Webview (rect)'),
@@ -241,7 +259,8 @@ class _MyHomePageState extends State<MyHomePage> {
             ),
             RaisedButton(
               onPressed: () {
-                final future = flutterWebViewPlugin.evalJavascript(_codeCtrl.text);
+                final future =
+                    flutterWebViewPlugin.evalJavascript(_codeCtrl.text);
                 future.then((String result) {
                   setState(() {
                     _history.add('eval: $result');

ios/Classes/FlutterWebviewPlugin.m

@@ -1,4 +1,5 @@
 #import "FlutterWebviewPlugin.h"
+#import "JavaScriptChannelHandler.h"
 
 static NSString *const CHANNEL_NAME = @"flutter_webview_plugin";
 
@@ -7,6 +8,7 @@ static NSString *const CHANNEL_NAME = @"flutter_webview_plugin";
     BOOL _enableAppScheme;
     BOOL _enableZoom;
     NSString* _invalidUrlRegex;
+    NSMutableSet* _javaScriptChannelNames;
 }
 @end
 
@@ -86,6 +88,15 @@ static NSString *const CHANNEL_NAME = @"flutter_webview_plugin";
     NSNumber *scrollBar = call.arguments[@"scrollBar"];
     NSNumber *withJavascript = call.arguments[@"withJavascript"];
     _invalidUrlRegex = call.arguments[@"invalidUrlRegex"];
+    
+    _javaScriptChannelNames = [[NSMutableSet alloc] init];
+    
+    WKUserContentController* userContentController = [[WKUserContentController alloc] init];
+    if ([call.arguments[@"javascriptChannelNames"] isKindOfClass:[NSArray class]]) {
+        NSArray* javaScriptChannelNames = call.arguments[@"javascriptChannelNames"];
+        [_javaScriptChannelNames addObjectsFromArray:javaScriptChannelNames];
+        [self registerJavaScriptChannels:_javaScriptChannelNames controller:userContentController];
+    }
 
     if (clearCache != (id)[NSNull null] && [clearCache boolValue]) {
         [[NSURLCache sharedURLCache] removeAllCachedResponses];
@@ -117,7 +128,9 @@ static NSString *const CHANNEL_NAME = @"flutter_webview_plugin";
         rc = self.viewController.view.bounds;
     }
 
-    self.webview = [[WKWebView alloc] initWithFrame:rc];
+    WKWebViewConfiguration* configuration = [[WKWebViewConfiguration alloc] init];
+    configuration.userContentController = userContentController;
+    self.webview = [[WKWebView alloc] initWithFrame:rc configuration:configuration];
     self.webview.UIDelegate = self;
     self.webview.navigationDelegate = self;
     self.webview.scrollView.delegate = self;
@@ -362,6 +375,23 @@ static NSString *const CHANNEL_NAME = @"flutter_webview_plugin";
     decisionHandler(WKNavigationResponsePolicyAllow);
 }
 
+- (void)registerJavaScriptChannels:(NSSet*)channelNames
+                        controller:(WKUserContentController*)userContentController {
+    for (NSString* channelName in channelNames) {
+        FLTJavaScriptChannel* _channel =
+        [[FLTJavaScriptChannel alloc] initWithMethodChannel: channel
+                                      javaScriptChannelName:channelName];
+        [userContentController addScriptMessageHandler:_channel name:channelName];
+        NSString* wrapperSource = [NSString
+                                   stringWithFormat:@"window.%@ = webkit.messageHandlers.%@;", channelName, channelName];
+        WKUserScript* wrapperScript =
+        [[WKUserScript alloc] initWithSource:wrapperSource
+                               injectionTime:WKUserScriptInjectionTimeAtDocumentStart
+                            forMainFrameOnly:NO];
+        [userContentController addUserScript:wrapperScript];
+    }
+}
+
 #pragma mark -- UIScrollViewDelegate
 - (void)scrollViewWillBeginDragging:(UIScrollView *)scrollView {
     if (scrollView.pinchGestureRecognizer.isEnabled != _enableZoom) {

ios/Classes/JavaScriptChannelHandler.h

@@ -0,0 +1,17 @@
+// Copyright 2019 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#import <Flutter/Flutter.h>
+#import <WebKit/WebKit.h>
+
+NS_ASSUME_NONNULL_BEGIN
+
+@interface FLTJavaScriptChannel : NSObject <WKScriptMessageHandler>
+
+- (instancetype)initWithMethodChannel:(FlutterMethodChannel*)methodChannel
+                javaScriptChannelName:(NSString*)javaScriptChannelName;
+
+@end
+
+NS_ASSUME_NONNULL_END

ios/Classes/JavaScriptChannelHandler.m

@@ -0,0 +1,36 @@
+// Copyright 2019 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#import "JavaScriptChannelHandler.h"
+
+@implementation FLTJavaScriptChannel {
+  FlutterMethodChannel* _methodChannel;
+  NSString* _javaScriptChannelName;
+}
+
+- (instancetype)initWithMethodChannel:(FlutterMethodChannel*)methodChannel
+                javaScriptChannelName:(NSString*)javaScriptChannelName {
+  self = [super init];
+  NSAssert(methodChannel != nil, @"methodChannel must not be null.");
+  NSAssert(javaScriptChannelName != nil, @"javaScriptChannelName must not be null.");
+  if (self) {
+    _methodChannel = methodChannel;
+    _javaScriptChannelName = javaScriptChannelName;
+  }
+  return self;
+}
+
+- (void)userContentController:(WKUserContentController*)userContentController
+      didReceiveScriptMessage:(WKScriptMessage*)message {
+  NSAssert(_methodChannel != nil, @"Can't send a message to an unitialized JavaScript channel.");
+  NSAssert(_javaScriptChannelName != nil,
+           @"Can't send a message to an unitialized JavaScript channel.");
+  NSDictionary* arguments = @{
+    @"channel" : _javaScriptChannelName,
+    @"message" : [NSString stringWithFormat:@"%@", message.body]
+  };
+  [_methodChannel invokeMethod:@"javascriptChannelMessage" arguments:arguments];
+}
+
+@end

lib/flutter_webview_plugin.dart

@@ -1,4 +1,6 @@
 library flutter_webview_plugin;
 
 export 'src/base.dart';
+export 'src/javascript_channel.dart';
+export 'src/javascript_message.dart';
 export 'src/webview_scaffold.dart';

lib/src/base.dart

@@ -3,6 +3,9 @@ import 'dart:ui';
 
 import 'package:flutter/material.dart';
 import 'package:flutter/services.dart';
+import 'package:flutter_webview_plugin/src/javascript_channel.dart';
+
+import 'javascript_message.dart';
 
 const _kChannel = 'flutter_webview_plugin';
 
@@ -31,6 +34,12 @@ class FlutterWebviewPlugin {
   final _onScrollYChanged = StreamController<double>.broadcast();
   final _onProgressChanged = new StreamController<double>.broadcast();
   final _onHttpError = StreamController<WebViewHttpError>.broadcast();
+  final _onPostMessage = StreamController<JavascriptMessage>.broadcast();
+
+  final Map<String, JavascriptChannel> _javascriptChannels =
+      // ignoring warning as min SDK version doesn't support collection literals yet
+      // ignore: prefer_collection_literals
+      Map<String, JavascriptChannel>();
 
   Future<Null> _handleMessages(MethodCall call) async {
     switch (call.method) {
@@ -49,8 +58,8 @@ class FlutterWebviewPlugin {
       case 'onScrollYChanged':
         _onScrollYChanged.add(call.arguments['yDirection']);
         break;
-      case "onProgressChanged":
-        _onProgressChanged.add(call.arguments["progress"]);
+      case 'onProgressChanged':
+        _onProgressChanged.add(call.arguments['progress']);
         break;
       case 'onState':
         _onStateChanged.add(
@@ -60,7 +69,12 @@ class FlutterWebviewPlugin {
         );
         break;
       case 'onHttpError':
-        _onHttpError.add(WebViewHttpError(call.arguments['code'], call.arguments['url']));
+        _onHttpError.add(
+            WebViewHttpError(call.arguments['code'], call.arguments['url']));
+        break;
+      case 'javascriptChannelMessage':
+        _handleJavascriptChannelMessage(
+            call.arguments['channel'], call.arguments['message']);
         break;
     }
   }
@@ -119,8 +133,10 @@ class FlutterWebviewPlugin {
   /// - [displayZoomControls]: display zoom controls on webview
   /// - [withOverviewMode]: enable overview mode for Android webview ( setLoadWithOverviewMode )
   /// - [useWideViewPort]: use wide viewport for Android webview ( setUseWideViewPort )
-  Future<Null> launch(String url, {
+  Future<Null> launch(
+    String url, {
     Map<String, String> headers,
+    Set<JavascriptChannel> javascriptChannels,
     bool withJavascript,
     bool clearCache,
     bool clearCookies,
@@ -171,6 +187,21 @@ class FlutterWebviewPlugin {
       args['headers'] = headers;
     }
 
+    _assertJavascriptChannelNamesAreUnique(javascriptChannels);
+
+    if (javascriptChannels != null) {
+      javascriptChannels.forEach((channel) {
+        _javascriptChannels[channel.name] = channel;
+      });
+    } else {
+      if (_javascriptChannels.isNotEmpty) {
+        _javascriptChannels.clear();
+      }
+    }
+
+    args['javascriptChannelNames'] =
+        _extractJavascriptChannelNames(javascriptChannels).toList();
+
     if (rect != null) {
       args['rect'] = {
         'left': rect.left,
@@ -190,7 +221,10 @@ class FlutterWebviewPlugin {
 
   /// Close the Webview
   /// Will trigger the [onDestroy] event
-  Future<Null> close() async => await _channel.invokeMethod('close');
+  Future<Null> close() async {
+    _javascriptChannels.clear();
+    await _channel.invokeMethod('close');
+  }
 
   /// Reloads the WebView.
   Future<Null> reload() async => await _channel.invokeMethod('reload');
@@ -217,10 +251,12 @@ class FlutterWebviewPlugin {
   }
 
   // Clean cookies on WebView
-  Future<Null> cleanCookies() async => await _channel.invokeMethod('cleanCookies');
+  Future<Null> cleanCookies() async =>
+      await _channel.invokeMethod('cleanCookies');
 
   // Stops current loading process
-  Future<Null> stopLoading() async => await _channel.invokeMethod('stopLoading');
+  Future<Null> stopLoading() async =>
+      await _channel.invokeMethod('stopLoading');
 
   /// Close all Streams
   void dispose() {
@@ -231,6 +267,7 @@ class FlutterWebviewPlugin {
     _onScrollXChanged.close();
     _onScrollYChanged.close();
     _onHttpError.close();
+    _onPostMessage.close();
     _instance = null;
   }
 
@@ -259,6 +296,29 @@ class FlutterWebviewPlugin {
     };
     await _channel.invokeMethod('resize', args);
   }
+
+  Set<String> _extractJavascriptChannelNames(Set<JavascriptChannel> channels) {
+    final Set<String> channelNames = channels == null
+        // ignore: prefer_collection_literals
+        ? Set<String>()
+        : channels.map((JavascriptChannel channel) => channel.name).toSet();
+    return channelNames;
+  }
+
+  void _handleJavascriptChannelMessage(
+      final String channelName, final String message) {
+    _javascriptChannels[channelName]
+        .onMessageReceived(JavascriptMessage(message));
+  }
+
+  void _assertJavascriptChannelNamesAreUnique(
+      final Set<JavascriptChannel> channels) {
+    if (channels == null || channels.isEmpty) {
+      return;
+    }
+
+    assert(_extractJavascriptChannelNames(channels).length == channels.length);
+  }
 }
 
 class WebViewStateChanged {

lib/src/javascript_channel.dart

@@ -0,0 +1,36 @@
+import 'package:meta/meta.dart';
+import 'package:flutter_webview_plugin/flutter_webview_plugin.dart';
+
+final RegExp _validChannelNames = RegExp('^[a-zA-Z_][a-zA-Z0-9]*\$');
+
+/// A named channel for receiving messaged from JavaScript code running inside a web view.
+class JavascriptChannel {
+  /// Constructs a Javascript channel.
+  ///
+  /// The parameters `name` and `onMessageReceived` must not be null.
+  JavascriptChannel({
+    @required this.name,
+    @required this.onMessageReceived,
+  })  : assert(name != null),
+        assert(onMessageReceived != null),
+        assert(_validChannelNames.hasMatch(name));
+
+  /// The channel's name.
+  ///
+  /// Passing this channel object as part of a [WebView.javascriptChannels] adds a channel object to
+  /// the Javascript window object's property named `name`.
+  ///
+  /// The name must start with a letter or underscore(_), followed by any combination of those
+  /// characters plus digits.
+  ///
+  /// Note that any JavaScript existing `window` property with this name will be overriden.
+  ///
+  /// See also [WebView.javascriptChannels] for more details on the channel registration mechanism.
+  final String name;
+
+  /// A callback that's invoked when a message is received through the channel.
+  final JavascriptMessageHandler onMessageReceived;
+}
+
+/// Callback type for handling messages sent from Javascript running in a web view.
+typedef void JavascriptMessageHandler(JavascriptMessage message);

lib/src/javascript_message.dart

@@ -0,0 +1,11 @@
+/// A message that was sent by JavaScript code running in a [WebView].
+
+class JavascriptMessage {
+  /// Constructs a JavaScript message object.
+  ///
+  /// The `message` parameter must not be null.
+  const JavascriptMessage(this.message) : assert(message != null);
+
+  /// The contents of the message that was sent by the JavaScript code.
+  final String message;
+}

lib/src/webview_scaffold.dart

@@ -3,16 +3,17 @@ import 'dart:async';
 import 'package:flutter/foundation.dart';
 import 'package:flutter/material.dart';
 import 'package:flutter/rendering.dart';
+import 'package:flutter_webview_plugin/src/javascript_channel.dart';
 
 import 'base.dart';
 
 class WebviewScaffold extends StatefulWidget {
-
   const WebviewScaffold({
     Key key,
     this.appBar,
     @required this.url,
     this.headers,
+    this.javascriptChannels,
     this.withJavascript,
     this.clearCache,
     this.clearCookies,
@@ -43,6 +44,7 @@ class WebviewScaffold extends StatefulWidget {
   final PreferredSizeWidget appBar;
   final String url;
   final Map<String, String> headers;
+  final Set<JavascriptChannel> javascriptChannels;
   final bool withJavascript;
   final bool clearCache;
   final bool clearCookies;
@@ -87,7 +89,9 @@ class _WebviewScaffoldState extends State<WebviewScaffold> {
     webviewReference.close();
 
     _onBack = webviewReference.onBack.listen((_) async {
-      if (!mounted) return;
+      if (!mounted) {
+        return;
+      }
 
       // The willPop/pop pair here is equivalent to Navigator.maybePop(),
       // which is what's called from the flutter back button handler.
@@ -148,6 +152,7 @@ class _WebviewScaffoldState extends State<WebviewScaffold> {
             webviewReference.launch(
               widget.url,
               headers: widget.headers,
+              javascriptChannels: widget.javascriptChannels,
               withJavascript: widget.withJavascript,
               clearCache: widget.clearCache,
               clearCookies: widget.clearCookies,
@@ -181,7 +186,8 @@ class _WebviewScaffoldState extends State<WebviewScaffold> {
             }
           }
         },
-        child: widget.initialChild ?? const Center(child: const CircularProgressIndicator()),
+        child: widget.initialChild ??
+            const Center(child: const CircularProgressIndicator()),
       ),
     );
   }
@@ -204,7 +210,8 @@ class _WebviewPlaceholder extends SingleChildRenderObjectWidget {
   }
 
   @override
-  void updateRenderObject(BuildContext context, _WebviewPlaceholderRender renderObject) {
+  void updateRenderObject(
+      BuildContext context, _WebviewPlaceholderRender renderObject) {
     renderObject..onRectChanged = onRectChanged;
   }
 }