[webview_flutter] [url_launcher] Handle Multiwindows in WebViews

packages/url_launcher/url_launcher/android/src/main/java/io/flutter/plugins/urllauncher/WebViewActivity.java

@@ -1,17 +1,21 @@
 package io.flutter.plugins.urllauncher;
 
+import android.annotation.TargetApi;
 import android.app.Activity;
 import android.content.BroadcastReceiver;
 import android.content.Context;
 import android.content.Intent;
 import android.content.IntentFilter;
 import android.os.Build;
 import android.os.Bundle;
+import android.os.Message;
 import android.provider.Browser;
 import android.view.KeyEvent;
+import android.webkit.WebChromeClient;
 import android.webkit.WebResourceRequest;
 import android.webkit.WebView;
 import android.webkit.WebViewClient;
+import androidx.annotation.NonNull;
 import java.util.HashMap;
 import java.util.Map;
 
@@ -60,6 +64,48 @@ public boolean shouldOverrideUrlLoading(WebView view, WebResourceRequest request
 
   private IntentFilter closeIntentFilter = new IntentFilter(ACTION_CLOSE);
 
+  // Verifies that a url opened by `Window.open` has a secure url.
+  private class FlutterWebChromeClient extends WebChromeClient {
+    @Override
+    public boolean onCreateWindow(
+        final WebView view, boolean isDialog, boolean isUserGesture, Message resultMsg) {
+      final WebViewClient webViewClient =
+          new WebViewClient() {
+            @TargetApi(Build.VERSION_CODES.LOLLIPOP)
+            @Override
+            public boolean shouldOverrideUrlLoading(
+                @NonNull WebView view, @NonNull WebResourceRequest request) {
+              final String url = request.getUrl().toString();
+              if (isSecure(url)) {
+                webview.loadUrl(url);
+              }
+              return true;
+            }
+
+            @Override
+            public boolean shouldOverrideUrlLoading(WebView view, String url) {
+              if (isSecure(url)) {
+                webview.loadUrl(url);
+              }
+              return true;
+            }
+          };
+
+      final WebView newWebView = new WebView(webview.getContext());
+      newWebView.setWebViewClient(webViewClient);
+
+      final WebView.WebViewTransport transport = (WebView.WebViewTransport) resultMsg.obj;
+      transport.setWebView(newWebView);
+      resultMsg.sendToTarget();
+
+      return true;
+    }
+
+    private boolean isSecure(String url) {
+      return url.startsWith("https://") || url.startsWith("http://");
+    }
+  }
+
   @Override
   public void onCreate(Bundle savedInstanceState) {
     super.onCreate(savedInstanceState);
@@ -81,6 +127,10 @@ public void onCreate(Bundle savedInstanceState) {
     // Open new urls inside the webview itself.
     webview.setWebViewClient(webViewClient);
 
+    // Multi windows is set with FlutterWebChromeClient by default to handle internal bug: b/159892679.
+    webview.getSettings().setSupportMultipleWindows(true);
+    webview.setWebChromeClient(new FlutterWebChromeClient());
+
     // Register receiver that may finish this Activity.
     registerReceiver(broadcastReceiver, closeIntentFilter);
   }

packages/webview_flutter/android/src/main/java/io/flutter/plugins/webviewflutter/FlutterWebView.java

@@ -9,9 +9,14 @@
 import android.hardware.display.DisplayManager;
 import android.os.Build;
 import android.os.Handler;
+import android.os.Message;
 import android.view.View;
+import android.webkit.WebChromeClient;
+import android.webkit.WebResourceRequest;
 import android.webkit.WebStorage;
+import android.webkit.WebView;
 import android.webkit.WebViewClient;
+import androidx.annotation.NonNull;
 import io.flutter.plugin.common.BinaryMessenger;
 import io.flutter.plugin.common.MethodCall;
 import io.flutter.plugin.common.MethodChannel;
@@ -29,6 +34,48 @@ public class FlutterWebView implements PlatformView, MethodCallHandler {
   private final FlutterWebViewClient flutterWebViewClient;
   private final Handler platformThreadHandler;
 
+  // Verifies that a url opened by `Window.open` has a secure url.
+  private class FlutterWebChromeClient extends WebChromeClient {
+    @Override
+    public boolean onCreateWindow(
+        final WebView view, boolean isDialog, boolean isUserGesture, Message resultMsg) {
+      final WebViewClient webViewClient =
+          new WebViewClient() {
+            @TargetApi(Build.VERSION_CODES.LOLLIPOP)
+            @Override
+            public boolean shouldOverrideUrlLoading(
+                @NonNull WebView view, @NonNull WebResourceRequest request) {
+              final String url = request.getUrl().toString();
+              if (isSecure(url)) {
+                flutterWebViewClient.shouldOverrideUrlLoading(FlutterWebView.this.webView, request);
+              }
+              return true;
+            }
+
+            @Override
+            public boolean shouldOverrideUrlLoading(WebView view, String url) {
+              if (isSecure(url)) {
+                flutterWebViewClient.shouldOverrideUrlLoading(FlutterWebView.this.webView, url);
+              }
+              return true;
+            }
+          };
+
+      final WebView newWebView = new WebView(view.getContext());
+      newWebView.setWebViewClient(webViewClient);
+
+      final WebView.WebViewTransport transport = (WebView.WebViewTransport) resultMsg.obj;
+      transport.setWebView(newWebView);
+      resultMsg.sendToTarget();
+
+      return true;
+    }
+
+    private boolean isSecure(String url) {
+      return url.startsWith("https://") || url.startsWith("http://");
+    }
+  }
+
   @TargetApi(Build.VERSION_CODES.JELLY_BEAN_MR1)
   @SuppressWarnings("unchecked")
   FlutterWebView(
@@ -50,6 +97,10 @@ public class FlutterWebView implements PlatformView, MethodCallHandler {
     webView.getSettings().setDomStorageEnabled(true);
     webView.getSettings().setJavaScriptCanOpenWindowsAutomatically(true);
 
+    // Multi windows is set with FlutterWebChromeClient by default to handle internal bug: b/159892679.
+    webView.getSettings().setSupportMultipleWindows(true);
+    webView.setWebChromeClient(new FlutterWebChromeClient());
+
     methodChannel = new MethodChannel(messenger, "plugins.flutter.io/webview_" + id);
     methodChannel.setMethodCallHandler(this);
 

packages/webview_flutter/android/src/main/java/io/flutter/plugins/webviewflutter/FlutterWebViewClient.java

@@ -77,7 +77,7 @@ private static String errorCodeToString(int errorCode) {
   }
 
   @TargetApi(Build.VERSION_CODES.LOLLIPOP)
-  private boolean shouldOverrideUrlLoading(WebView view, WebResourceRequest request) {
+  boolean shouldOverrideUrlLoading(WebView view, WebResourceRequest request) {
     if (!hasNavigationDelegate) {
       return false;
     }
@@ -97,7 +97,7 @@ private boolean shouldOverrideUrlLoading(WebView view, WebResourceRequest reques
     return request.isForMainFrame();
   }
 
-  private boolean shouldOverrideUrlLoading(WebView view, String url) {
+  boolean shouldOverrideUrlLoading(WebView view, String url) {
     if (!hasNavigationDelegate) {
       return false;
     }