[webview_flutter_android] Fixes bug where a AndroidNavigationDelegate was required to load a request (#6872)

* fix bug

* comment

* another test

* fix spelling

Author: bparrishMines

packages/webview_flutter/webview_flutter_android/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 3.1.1
+
+* Fixes bug where a `AndroidNavigationDelegate` was required to load a request.
+
 ## 3.1.0
 
 * Adds support for selecting Hybrid Composition on versions 23+. Please use

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

@@ -29,9 +29,8 @@ public class WebChromeClientHostApiImpl implements WebChromeClientHostApi {
   /**
    * Implementation of {@link WebChromeClient} that passes arguments of callback methods to Dart.
    */
-  public static class WebChromeClientImpl extends WebChromeClient {
+  public static class WebChromeClientImpl extends SecureWebChromeClient {
     private final WebChromeClientFlutterApiImpl flutterApi;
-    @Nullable private WebViewClient webViewClient;
 
     /**
      * Creates a {@link WebChromeClient} that passes arguments of callbacks methods to Dart.
@@ -42,6 +41,19 @@ public WebChromeClientImpl(@NonNull WebChromeClientFlutterApiImpl flutterApi) {
       this.flutterApi = flutterApi;
     }
 
+    @Override
+    public void onProgressChanged(WebView view, int progress) {
+      flutterApi.onProgressChanged(this, view, (long) progress, reply -> {});
+    }
+  }
+
+  /**
+   * Implementation of {@link WebChromeClient} that only allows secure urls when opening a new
+   * window.
+   */
+  public static class SecureWebChromeClient extends WebChromeClient {
+    @Nullable private WebViewClient webViewClient;
+
     @Override
     public boolean onCreateWindow(
         final WebView view, boolean isDialog, boolean isUserGesture, Message resultMsg) {
@@ -105,11 +117,6 @@ public boolean shouldOverrideUrlLoading(WebView windowWebView, String url) {
       return true;
     }
 
-    @Override
-    public void onProgressChanged(WebView view, int progress) {
-      flutterApi.onProgressChanged(this, view, (long) progress, reply -> {});
-    }
-
     /**
      * Set the {@link WebViewClient} that calls to {@link WebChromeClient#onCreateWindow} are passed
      * to.

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

@@ -17,7 +17,6 @@
 import io.flutter.plugin.common.BinaryMessenger;
 import io.flutter.plugin.platform.PlatformView;
 import io.flutter.plugins.webviewflutter.GeneratedAndroidWebView.WebViewHostApi;
-import io.flutter.plugins.webviewflutter.WebChromeClientHostApiImpl.WebChromeClientImpl;
 import java.util.Map;
 import java.util.Objects;
 
@@ -80,7 +79,7 @@ public void setWebContentsDebuggingEnabled(boolean enabled) {
   /** Implementation of {@link WebView} that can be used as a Flutter {@link PlatformView}s. */
   public static class WebViewPlatformView extends WebView implements PlatformView {
     private WebViewClient currentWebViewClient;
-    private WebChromeClientImpl currentWebChromeClient;
+    private WebChromeClientHostApiImpl.SecureWebChromeClient currentWebChromeClient;
 
     /**
      * Creates a {@link WebViewPlatformView}.
@@ -91,9 +90,7 @@ public WebViewPlatformView(
         Context context, BinaryMessenger binaryMessenger, InstanceManager instanceManager) {
       super(context);
       currentWebViewClient = new WebViewClient();
-      currentWebChromeClient =
-          new WebChromeClientImpl(
-              new WebChromeClientFlutterApiImpl(binaryMessenger, instanceManager));
+      currentWebChromeClient = new WebChromeClientHostApiImpl.SecureWebChromeClient();
 
       setWebViewClient(currentWebViewClient);
       setWebChromeClient(currentWebChromeClient);
@@ -119,12 +116,21 @@ public void setWebViewClient(WebViewClient webViewClient) {
     @Override
     public void setWebChromeClient(WebChromeClient client) {
       super.setWebChromeClient(client);
-      if (!(client instanceof WebChromeClientImpl)) {
-        throw new AssertionError("Client must be a WebChromeClientImpl.");
+      if (!(client instanceof WebChromeClientHostApiImpl.SecureWebChromeClient)) {
+        throw new AssertionError("Client must be a SecureWebChromeClient.");
       }
-      currentWebChromeClient = (WebChromeClientImpl) client;
+      currentWebChromeClient = (WebChromeClientHostApiImpl.SecureWebChromeClient) client;
       currentWebChromeClient.setWebViewClient(currentWebViewClient);
     }
+
+    // When running unit tests, the parent `WebView` class is replaced by a stub that returns null
+    // for every method. This is overridden so that this returns the current WebChromeClient during
+    // unit tests. This should only remain overridden as long as `setWebChromeClient` is overridden.
+    @Nullable
+    @Override
+    public WebChromeClient getWebChromeClient() {
+      return currentWebChromeClient;
+    }
   }
 
   /**
@@ -135,7 +141,7 @@ public void setWebChromeClient(WebChromeClient client) {
   public static class InputAwareWebViewPlatformView extends InputAwareWebView
       implements PlatformView {
     private WebViewClient currentWebViewClient;
-    private WebChromeClientImpl currentWebChromeClient;
+    private WebChromeClientHostApiImpl.SecureWebChromeClient currentWebChromeClient;
 
     /**
      * Creates a {@link InputAwareWebViewPlatformView}.
@@ -149,9 +155,7 @@ public InputAwareWebViewPlatformView(
         View containerView) {
       super(context, containerView);
       currentWebViewClient = new WebViewClient();
-      currentWebChromeClient =
-          new WebChromeClientImpl(
-              new WebChromeClientFlutterApiImpl(binaryMessenger, instanceManager));
+      currentWebChromeClient = new WebChromeClientHostApiImpl.SecureWebChromeClient();
 
       setWebViewClient(currentWebViewClient);
       setWebChromeClient(currentWebChromeClient);
@@ -198,10 +202,10 @@ public void setWebViewClient(WebViewClient webViewClient) {
     @Override
     public void setWebChromeClient(WebChromeClient client) {
       super.setWebChromeClient(client);
-      if (!(client instanceof WebChromeClientImpl)) {
-        throw new AssertionError("Client must be a WebChromeClientImpl.");
+      if (!(client instanceof WebChromeClientHostApiImpl.SecureWebChromeClient)) {
+        throw new AssertionError("Client must be a SecureWebChromeClient.");
       }
-      currentWebChromeClient = (WebChromeClientImpl) client;
+      currentWebChromeClient = (WebChromeClientHostApiImpl.SecureWebChromeClient) client;
       currentWebChromeClient.setWebViewClient(currentWebViewClient);
     }
   }

packages/webview_flutter/webview_flutter_android/android/src/test/java/io/flutter/plugins/webviewflutter/WebViewTest.java

@@ -5,6 +5,8 @@
 package io.flutter.plugins.webviewflutter;
 
 import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertTrue;
 import static org.mockito.ArgumentMatchers.eq;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.verify;
@@ -18,6 +20,7 @@
 import io.flutter.plugin.common.BinaryMessenger;
 import io.flutter.plugins.webviewflutter.WebViewHostApiImpl.WebViewPlatformView;
 import java.util.HashMap;
+import java.util.Objects;
 import org.junit.After;
 import org.junit.Before;
 import org.junit.Rule;
@@ -262,4 +265,20 @@ public void setWebChromeClient() {
     testHostApiImpl.setWebChromeClient(0L, 1L);
     verify(mockWebView).setWebChromeClient(mockWebChromeClient);
   }
+
+  @Test
+  public void defaultWebChromeClientIsSecureWebChromeClient() {
+    final WebViewPlatformView webView = new WebViewPlatformView(mockContext, null, null);
+    assertTrue(
+        webView.getWebChromeClient() instanceof WebChromeClientHostApiImpl.SecureWebChromeClient);
+    assertFalse(
+        webView.getWebChromeClient() instanceof WebChromeClientHostApiImpl.WebChromeClientImpl);
+  }
+
+  @Test
+  public void defaultWebChromeClientDoesNotAttemptToCommunicateWithDart() {
+    final WebViewPlatformView webView = new WebViewPlatformView(mockContext, null, null);
+    // This shouldn't throw an Exception.
+    Objects.requireNonNull(webView.getWebChromeClient()).onProgressChanged(webView, 0);
+  }
 }

packages/webview_flutter/webview_flutter_android/pubspec.yaml

@@ -2,7 +2,7 @@ name: webview_flutter_android
 description: A Flutter plugin that provides a WebView widget on Android.
 repository: https://github.com/flutter/plugins/tree/main/packages/webview_flutter/webview_flutter_android
 issue_tracker: https://github.com/flutter/flutter/issues?q=is%3Aissue+is%3Aopen+label%3A%22p%3A+webview%22
-version: 3.1.0
+version: 3.1.1
 
 environment:
   sdk: ">=2.17.0 <3.0.0"