Implement JavaScript dialog feature on android

packages/webview_flutter/webview_flutter_android/CHANGELOG.md

@@ -1,3 +1,7 @@
+## 3.10.2
+
+* Add support to show JavaScript dialog. Sees `PlatformWebViewController.setJavaScriptAlertDialogCallback`, `PlatformWebViewController.setJavaScriptConfirmDialogCallback` and `PlatformWebViewController.setJavaScriptTextInputDialogCallback`.
+
 ## 3.10.1
 
 * Bumps androidx.annotation:annotation from 1.5.0 to 1.7.0.

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

@@ -11,6 +11,7 @@
 import android.webkit.WebChromeClient;
 import android.webkit.WebView;
 import androidx.annotation.NonNull;
+import androidx.annotation.Nullable;
 import androidx.annotation.RequiresApi;
 import io.flutter.plugin.common.BinaryMessenger;
 import io.flutter.plugins.webviewflutter.GeneratedAndroidWebView.WebChromeClientFlutterApi;
@@ -149,6 +150,49 @@ public void onHideCustomView(
         callback);
   }
 
+  /**
+   * Sends a message to Dart to call `WebChromeClient.runJavaScriptDialog` on the Dart object
+   * representing `instance`.
+   */
+
+  public void onHandleJavaScriptAlert(
+          @NonNull WebChromeClient instance,
+          @NonNull String message,
+          @NonNull WebChromeClientFlutterApi.Reply<Void> callback
+            ) {
+    super.onHandleJavaScriptAlert(
+            Objects.requireNonNull(instanceManager.getIdentifierForStrongReference(instance)),
+            message,
+            callback
+    );
+  }
+
+  public void onHandleJavaScriptConfirm(
+          @NonNull WebChromeClient instance,
+          @NonNull String message,
+          @NonNull WebChromeClientFlutterApi.Reply<Boolean> callback
+  ) {
+    super.onHandleJavaScriptConfirm(
+            Objects.requireNonNull(instanceManager.getIdentifierForStrongReference(instance)),
+            message,
+            callback
+    );
+  }
+
+  public void onHandleJavaScriptPrompt(
+          @NonNull WebChromeClient instance,
+          @NonNull String message,
+          @Nullable String defaultText,
+          @NonNull WebChromeClientFlutterApi.Reply<String> callback
+  ) {
+    super.onHandleJavaScriptPrompt(
+            Objects.requireNonNull(instanceManager.getIdentifierForStrongReference(instance)),
+            message,
+            defaultText,
+            callback
+    );
+  }
+
   private long getIdentifierForClient(WebChromeClient webChromeClient) {
     final Long identifier = instanceManager.getIdentifierForStrongReference(webChromeClient);
     if (identifier == null) {

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

@@ -10,6 +10,8 @@
 import android.os.Message;
 import android.view.View;
 import android.webkit.GeolocationPermissions;
+import android.webkit.JsPromptResult;
+import android.webkit.JsResult;
 import android.webkit.PermissionRequest;
 import android.webkit.ValueCallback;
 import android.webkit.WebChromeClient;
@@ -41,6 +43,10 @@ public static class WebChromeClientImpl extends SecureWebChromeClient {
     private final WebChromeClientFlutterApiImpl flutterApi;
     private boolean returnValueForOnShowFileChooser = false;
 
+    private boolean hasJavaScriptAlertCallback = false;
+    private boolean hasJavaScriptConfirmCallback = false;
+    private boolean hasJavaScriptPromptCallback = false;
+
     /**
      * Creates a {@link WebChromeClient} that passes arguments of callbacks methods to Dart.
      *
@@ -111,6 +117,64 @@ public void onPermissionRequest(@NonNull PermissionRequest request) {
     public void setReturnValueForOnShowFileChooser(boolean value) {
       returnValueForOnShowFileChooser = value;
     }
+
+    public void setHasJavaScriptAlertCallback(boolean value) {
+      hasJavaScriptAlertCallback = value;
+    }
+
+    public void setHasJavaScriptConfirmCallback(boolean value) {
+      hasJavaScriptConfirmCallback = value;
+    }
+
+    public void setHasJavaScriptPromptCallback(boolean value) {
+      hasJavaScriptPromptCallback = value;
+    }
+
+
+    @Override
+    public boolean onJsAlert(WebView view, String url, String message, JsResult result) {
+      if( hasJavaScriptAlertCallback ) {
+        flutterApi.onHandleJavaScriptAlert(this, message, reply -> {
+          result.confirm();
+        });
+        return true;
+      } else {
+        return false;
+      }
+    }
+
+    @Override
+    public boolean onJsConfirm(WebView view, String url, String message, JsResult result) {
+      if( hasJavaScriptConfirmCallback ) {
+        flutterApi.onHandleJavaScriptConfirm(this, message, reply -> {
+          if(reply) {
+            result.confirm();
+          } else {
+            result.cancel();
+          }
+        });
+        return true;
+      } else {
+        return false;
+      }
+    }
+
+    @Override
+    public boolean onJsPrompt(WebView view, String url, String message, String defaultValue, JsPromptResult result) {
+      if( hasJavaScriptPromptCallback ) {
+        flutterApi.onHandleJavaScriptPrompt(this, message, defaultValue, reply -> {
+          @Nullable String inputMessage = reply;
+          if(inputMessage != null) {
+            result.confirm(inputMessage);
+          } else {
+            result.cancel();
+          }
+        });
+        return true;
+      } else {
+        return false;
+      }
+    }
   }
 
   /**
@@ -246,4 +310,20 @@ public void setSynchronousReturnValueForOnShowFileChooser(
         Objects.requireNonNull(instanceManager.getInstance(instanceId));
     webChromeClient.setReturnValueForOnShowFileChooser(value);
   }
+
+  public void setHasJavaScriptAlertCallback(@NonNull Long instanceId, @NonNull Boolean value) {
+    final WebChromeClientImpl webChromeClient =
+            Objects.requireNonNull(instanceManager.getInstance(instanceId));
+    webChromeClient.setHasJavaScriptAlertCallback(value);
+  }
+  public void setHasJavaScriptConfirmCallback(@NonNull Long instanceId, @NonNull Boolean value) {
+    final WebChromeClientImpl webChromeClient =
+            Objects.requireNonNull(instanceManager.getInstance(instanceId));
+    webChromeClient.setHasJavaScriptConfirmCallback(value);
+  }
+  public void setHasJavaScriptPromptCallback(@NonNull Long instanceId, @NonNull Boolean value) {
+    final WebChromeClientImpl webChromeClient =
+            Objects.requireNonNull(instanceManager.getInstance(instanceId));
+    webChromeClient.setHasJavaScriptPromptCallback(value);
+  }
 }

packages/webview_flutter/webview_flutter_android/example/lib/main.dart

@@ -73,6 +73,25 @@ const String kTransparentBackgroundPage = '''
 </html>
 ''';
 
+const String kAlertTestPage = '''
+<html>  
+   <head>     
+      <script type = "text/javascript">  
+            function showAlert() {      
+               alert ("This is an alert dialog box");  
+            }  
+      </script>       
+   </head>  
+     
+   <body>  
+      <p> Click the following button to see the effect </p>        
+      <form>  
+         <input type = "button" value = "Click me" onclick = "showAlert();" />  
+      </form>       
+   </body>  
+</html>  
+''';
+
 class WebViewExample extends StatefulWidget {
   const WebViewExample({super.key, this.cookieManager});
 
@@ -202,6 +221,7 @@ enum MenuOptions {
   transparentBackground,
   setCookie,
   videoExample,
+  javaScriptAlert,
 }
 
 class SampleMenu extends StatelessWidget {
@@ -265,6 +285,9 @@ class SampleMenu extends StatelessWidget {
           case MenuOptions.videoExample:
             _onVideoExample(context);
             break;
+          case MenuOptions.javaScriptAlert:
+            _onJavaScriptAlertExample(context);
+            break;
         }
       },
       itemBuilder: (BuildContext context) => <PopupMenuItem<MenuOptions>>[
@@ -325,6 +348,10 @@ class SampleMenu extends StatelessWidget {
           value: MenuOptions.videoExample,
           child: Text('Video example'),
         ),
+        const PopupMenuItem<MenuOptions>(
+          value: MenuOptions.javaScriptAlert,
+          child: Text('JavaScript Alert Example'),
+        ),
       ],
     );
   }
@@ -473,6 +500,14 @@ class SampleMenu extends StatelessWidget {
     return webViewController.loadHtmlString(kTransparentBackgroundPage);
   }
 
+  Future<void> _onJavaScriptAlertExample(BuildContext context) {
+    webViewController.setOnJavaScriptAlertDialogCallback((message) async {
+      return _showAlert(context, message);
+    });
+
+    return webViewController.loadHtmlString(kAlertTestPage);
+  }
+
   Widget _getCookieList(String cookies) {
     if (cookies == '""') {
       return Container();
@@ -497,6 +532,18 @@ class SampleMenu extends StatelessWidget {
 
     return indexFile.path;
   }
+
+  Future<void> _showAlert(BuildContext context, String message) async {
+    return showDialog(context: context, builder: (BuildContext ctx) {
+      return AlertDialog(content: Text(message),
+        actions: [
+          TextButton(onPressed: () {
+            Navigator.of(ctx).pop();
+          }, child: const Text('OK'))
+        ],
+      );
+    });
+  }
 }
 
 class NavigationControls extends StatelessWidget {

packages/webview_flutter/webview_flutter_android/example/pubspec.yaml

@@ -17,7 +17,8 @@ dependencies:
     # The example app is bundled with the plugin so we use a path dependency on
     # the parent directory to use the current plugin's version.
     path: ../
-  webview_flutter_platform_interface: ^2.4.0
+  webview_flutter_platform_interface:
+    path: ../../webview_flutter_platform_interface
 
 dev_dependencies:
   espresso: ^0.2.0

packages/webview_flutter/webview_flutter_android/lib/src/android_proxy.dart

@@ -50,6 +50,9 @@ class AndroidWebViewProxy {
             android_webview.CustomViewCallback callback)?
         onShowCustomView,
     void Function(android_webview.WebChromeClient instance)? onHideCustomView,
+    Future<void> Function(String message)? onHandleJavaScriptAlert,
+    Future<bool> Function(String message)? onHandleJavaScriptConfirm,
+    Future<String> Function(String message, String defaultText)? onHandleJavaScriptPrompt,
   }) createAndroidWebChromeClient;
 
   /// Constructs a [android_webview.WebViewClient].

packages/webview_flutter/webview_flutter_android/lib/src/android_webview.dart

@@ -1047,6 +1047,12 @@ class WebChromeClient extends JavaObject {
     this.onGeolocationPermissionsHidePrompt,
     this.onShowCustomView,
     this.onHideCustomView,
+    this.onHandleJavaScriptAlert,
+    this.onHandleJavaScriptConfirm,
+    this.onHandleJavaScriptPrompt,
+    this.hasJavaScriptAlertCallback,
+    this.hasJavaScriptConfirmCallback,
+    this.hasJavaScriptPromptCallback,
     @visibleForTesting super.binaryMessenger,
     @visibleForTesting super.instanceManager,
   }) : super.detached() {
@@ -1068,6 +1074,12 @@ class WebChromeClient extends JavaObject {
     this.onGeolocationPermissionsHidePrompt,
     this.onShowCustomView,
     this.onHideCustomView,
+    this.onHandleJavaScriptAlert,
+    this.onHandleJavaScriptConfirm,
+    this.onHandleJavaScriptPrompt,
+    this.hasJavaScriptAlertCallback,
+    this.hasJavaScriptConfirmCallback,
+    this.hasJavaScriptPromptCallback,
     super.binaryMessenger,
     super.instanceManager,
   }) : super.detached();
@@ -1121,6 +1133,14 @@ class WebChromeClient extends JavaObject {
   /// mode.
   final HideCustomViewCallback? onHideCustomView;
 
+  final Future<void> Function(String message)? onHandleJavaScriptAlert;
+  final Future<bool> Function(String message)? onHandleJavaScriptConfirm;
+  final Future<String> Function(String message, String defaultValue)? onHandleJavaScriptPrompt;
+
+  final bool Function()? hasJavaScriptAlertCallback;
+  final bool Function()? hasJavaScriptConfirmCallback;
+  final bool Function()? hasJavaScriptPromptCallback;
+
   /// Sets the required synchronous return value for the Java method,
   /// `WebChromeClient.onShowFileChooser(...)`.
   ///
@@ -1150,6 +1170,25 @@ class WebChromeClient extends JavaObject {
     );
   }
 
+  Future<void> setHasJavaScriptAlertCallback(
+    bool value,
+  ) {
+    return api.setHasJavaScriptAlertCallbackFromInstance(this, value);
+  }
+
+  Future<void> setHasJavaScriptConfirmCallback(
+      bool value,
+      ) {
+    return api.setHasJavaScriptConfirmCallbackFromInstance(this, value);
+  }
+
+  Future<void> setHasJavaScriptPromptCallback(
+      bool value,
+      ) {
+    return api.setHasJavaScriptPromptCallbackFromInstance(this, value);
+  }
+
+
   @override
   WebChromeClient copy() {
     return WebChromeClient.detached(
@@ -1160,6 +1199,12 @@ class WebChromeClient extends JavaObject {
       onGeolocationPermissionsHidePrompt: onGeolocationPermissionsHidePrompt,
       onShowCustomView: onShowCustomView,
       onHideCustomView: onHideCustomView,
+      onHandleJavaScriptAlert: onHandleJavaScriptAlert,
+      onHandleJavaScriptConfirm: onHandleJavaScriptConfirm,
+      onHandleJavaScriptPrompt: onHandleJavaScriptPrompt,
+      hasJavaScriptAlertCallback: hasJavaScriptAlertCallback,
+      hasJavaScriptConfirmCallback: hasJavaScriptConfirmCallback,
+      hasJavaScriptPromptCallback: hasJavaScriptPromptCallback,
       binaryMessenger: _api.binaryMessenger,
       instanceManager: _api.instanceManager,
     );