[webview_flutter_wkwebview] Implement WKNavigationDelegate.didFinishNavigation as a proof of concept for callback methods

packages/webview_flutter/webview_flutter_wkwebview/lib/src/common/function_flutter_api_impls.dart

@@ -0,0 +1,25 @@
+// Copyright 2013 The Flutter 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 'instance_manager.dart';
+import 'web_kit.pigeon.dart';
+
+/// Flutter api to dispose functions.
+class FunctionFlutterApiImpl extends FunctionFlutterApi {
+  /// Constructs a [FunctionFlutterApiImpl].
+  FunctionFlutterApiImpl({InstanceManager? instanceManager}) {
+    this.instanceManager = instanceManager ?? InstanceManager.instance;
+  }
+
+  /// Maintains instances stored to communicate with native language objects.
+  late final InstanceManager instanceManager;
+
+  @override
+  void dispose(int instanceId) {
+    final Function? function = instanceManager.getInstance(instanceId);
+    if (function != null) {
+      instanceManager.removeInstance(function);
+    }
+  }
+}

packages/webview_flutter/webview_flutter_wkwebview/lib/src/common/web_kit.pigeon.dart

@@ -1017,6 +1017,75 @@ class WKNavigationDelegateHostApi {
       return;
     }
   }
+
+  Future<void> setDidFinishNavigation(
+      int arg_instanceId, int? arg_functionInstanceId) async {
+    final BasicMessageChannel<Object?> channel = BasicMessageChannel<Object?>(
+        'dev.flutter.pigeon.WKNavigationDelegateHostApi.setDidFinishNavigation',
+        codec,
+        binaryMessenger: _binaryMessenger);
+    final Map<Object?, Object?>? replyMap =
+        await channel.send(<Object?>[arg_instanceId, arg_functionInstanceId])
+            as Map<Object?, Object?>?;
+    if (replyMap == null) {
+      throw PlatformException(
+        code: 'channel-error',
+        message: 'Unable to establish connection on channel.',
+      );
+    } else if (replyMap['error'] != null) {
+      final Map<Object?, Object?> error =
+          (replyMap['error'] as Map<Object?, Object?>?)!;
+      throw PlatformException(
+        code: (error['code'] as String?)!,
+        message: error['message'] as String?,
+        details: error['details'],
+      );
+    } else {
+      return;
+    }
+  }
+}
+
+class _WKNavigationDelegateFlutterApiCodec extends StandardMessageCodec {
+  const _WKNavigationDelegateFlutterApiCodec();
+}
+
+abstract class WKNavigationDelegateFlutterApi {
+  static const MessageCodec<Object?> codec =
+      _WKNavigationDelegateFlutterApiCodec();
+
+  void didFinishNavigation(
+      int functionInstanceId, int webViewInstanceId, String? url);
+  static void setup(WKNavigationDelegateFlutterApi? api,
+      {BinaryMessenger? binaryMessenger}) {
+    {
+      final BasicMessageChannel<Object?> channel = BasicMessageChannel<Object?>(
+          'dev.flutter.pigeon.WKNavigationDelegateFlutterApi.didFinishNavigation',
+          codec,
+          binaryMessenger: binaryMessenger);
+      if (api == null) {
+        channel.setMessageHandler(null);
+      } else {
+        channel.setMessageHandler((Object? message) async {
+          assert(message != null,
+              'Argument for dev.flutter.pigeon.WKNavigationDelegateFlutterApi.didFinishNavigation was null.');
+          final List<Object?> args = (message as List<Object?>?)!;
+          final int? arg_functionInstanceId = (args[0] as int?);
+          assert(arg_functionInstanceId != null,
+              'Argument for dev.flutter.pigeon.WKNavigationDelegateFlutterApi.didFinishNavigation was null, expected non-null int.');
+          final int? arg_webViewInstanceId = (args[1] as int?);
+          assert(arg_webViewInstanceId != null,
+              'Argument for dev.flutter.pigeon.WKNavigationDelegateFlutterApi.didFinishNavigation was null, expected non-null int.');
+          final String? arg_url = (args[2] as String?);
+          assert(arg_url != null,
+              'Argument for dev.flutter.pigeon.WKNavigationDelegateFlutterApi.didFinishNavigation was null, expected non-null String.');
+          api.didFinishNavigation(
+              arg_functionInstanceId!, arg_webViewInstanceId!, arg_url!);
+          return;
+        });
+      }
+    }
+  }
 }
 
 class _NSObjectHostApiCodec extends StandardMessageCodec {
@@ -1137,6 +1206,38 @@ class NSObjectHostApi {
   }
 }
 
+class _FunctionFlutterApiCodec extends StandardMessageCodec {
+  const _FunctionFlutterApiCodec();
+}
+
+abstract class FunctionFlutterApi {
+  static const MessageCodec<Object?> codec = _FunctionFlutterApiCodec();
+
+  void dispose(int instanceId);
+  static void setup(FunctionFlutterApi? api,
+      {BinaryMessenger? binaryMessenger}) {
+    {
+      final BasicMessageChannel<Object?> channel = BasicMessageChannel<Object?>(
+          'dev.flutter.pigeon.FunctionFlutterApi.dispose', codec,
+          binaryMessenger: binaryMessenger);
+      if (api == null) {
+        channel.setMessageHandler(null);
+      } else {
+        channel.setMessageHandler((Object? message) async {
+          assert(message != null,
+              'Argument for dev.flutter.pigeon.FunctionFlutterApi.dispose was null.');
+          final List<Object?> args = (message as List<Object?>?)!;
+          final int? arg_instanceId = (args[0] as int?);
+          assert(arg_instanceId != null,
+              'Argument for dev.flutter.pigeon.FunctionFlutterApi.dispose was null, expected non-null int.');
+          api.dispose(arg_instanceId!);
+          return;
+        });
+      }
+    }
+  }
+}
+
 class _WKWebViewHostApiCodec extends StandardMessageCodec {
   const _WKWebViewHostApiCodec();
   @override

packages/webview_flutter/webview_flutter_wkwebview/lib/src/foundation/foundation.dart

@@ -149,7 +149,11 @@ class NSObject {
       : _api = NSObjectHostApiImpl(
           binaryMessenger: binaryMessenger,
           instanceManager: instanceManager,
-        );
+        ) {
+    // Ensures FlutterApis for the Foundation library and FunctionFlutterApi are
+    // set up.
+    FoundationFlutterApis.instance.ensureSetUp();
+  }
 
   final NSObjectHostApiImpl _api;
 

packages/webview_flutter/webview_flutter_wkwebview/lib/src/foundation/foundation_api_impls.dart

@@ -2,8 +2,10 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+import 'package:flutter/foundation.dart';
 import 'package:flutter/services.dart';
 
+import '../common/function_flutter_api_impls.dart';
 import '../common/instance_manager.dart';
 import '../common/web_kit.pigeon.dart';
 import 'foundation.dart';
@@ -35,6 +37,54 @@ Iterable<NSKeyValueObservingOptionsEnumData>
   });
 }
 
+/// Handles initialization of Flutter APIs for the Foundation library.
+class FoundationFlutterApis {
+  /// Constructs a [FoundationFlutterApis].
+  @visibleForTesting
+  FoundationFlutterApis({
+    BinaryMessenger? binaryMessenger,
+    InstanceManager? instanceManager,
+  }) : _binaryMessenger = binaryMessenger {
+    functionFlutterApi =
+        FunctionFlutterApiImpl(instanceManager: instanceManager);
+  }
+
+  static FoundationFlutterApis _instance = FoundationFlutterApis();
+
+  /// Sets the global instance containing the Flutter Apis for the Foundation library.
+  @visibleForTesting
+  static set instance(FoundationFlutterApis instance) {
+    _instance = instance;
+  }
+
+  /// Global instance containing the Flutter Apis for the Foundation library.
+  static FoundationFlutterApis get instance {
+    return _instance;
+  }
+
+  final BinaryMessenger? _binaryMessenger;
+  bool _hasBeenSetUp = false;
+
+  /// Flutter Api for disposing functions.
+  ///
+  /// This FlutterApi is placed here because [FoundationFlutterApis.ensureSetUp]
+  /// is called inside [NSObject] and [NSObject] is the parent class of all
+  /// objects.
+  @visibleForTesting
+  late final FunctionFlutterApiImpl functionFlutterApi;
+
+  /// Ensures all the Flutter APIs have been set up to receive calls from native code.
+  void ensureSetUp() {
+    if (!_hasBeenSetUp) {
+      FunctionFlutterApi.setup(
+        functionFlutterApi,
+        binaryMessenger: _binaryMessenger,
+      );
+      _hasBeenSetUp = true;
+    }
+  }
+}
+
 /// Host api implementation for [NSObject].
 class NSObjectHostApiImpl extends NSObjectHostApi {
   /// Constructs an [NSObjectHostApiImpl].

packages/webview_flutter/webview_flutter_wkwebview/lib/src/web_kit/web_kit.dart

@@ -515,26 +515,28 @@ class WKUIDelegate {
 /// coordinate changes in your web view’s main frame.
 ///
 /// Wraps [WKNavigationDelegate](https://developer.apple.com/documentation/webkit/wknavigationdelegate?language=objc).
-class WKNavigationDelegate {
+class WKNavigationDelegate extends NSObject {
   /// Constructs a [WKNavigationDelegate].
   WKNavigationDelegate({
     BinaryMessenger? binaryMessenger,
     InstanceManager? instanceManager,
-  }) : _navigationDelegateApi = WKNavigationDelegateHostApiImpl(
+  })  : _navigationDelegateApi = WKNavigationDelegateHostApiImpl(
+          binaryMessenger: binaryMessenger,
+          instanceManager: instanceManager,
+        ),
+        super(
           binaryMessenger: binaryMessenger,
           instanceManager: instanceManager,
         ) {
+    WebKitFlutterApis.instance.ensureSetUp();
     _navigationDelegateApi.createForInstances(this);
   }
 
   final WKNavigationDelegateHostApiImpl _navigationDelegateApi;
 
   /// Called when navigation from the main frame has started.
   Future<void> setDidStartProvisionalNavigation(
-    void Function(
-      WKWebView webView,
-      String? url,
-    )?
+    void Function(WKWebView webView, String? url)?
         didStartProvisionalNavigation,
   ) {
     throw UnimplementedError();
@@ -544,7 +546,10 @@ class WKNavigationDelegate {
   Future<void> setDidFinishNavigation(
     void Function(WKWebView webView, String? url)? didFinishNavigation,
   ) {
-    throw UnimplementedError();
+    return _navigationDelegateApi.setDidFinishNavigationFromInstance(
+      this,
+      didFinishNavigation,
+    );
   }
 
   /// Called when permission is needed to navigate to new content.

packages/webview_flutter/webview_flutter_wkwebview/lib/src/web_kit/web_kit_api_impls.dart

@@ -2,6 +2,7 @@
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
+import 'package:flutter/foundation.dart';
 import 'package:flutter/services.dart';
 
 import '../common/instance_manager.dart';
@@ -106,6 +107,51 @@ extension _NSUrlRequestConverter on NSUrlRequest {
   }
 }
 
+/// Handles initialization of Flutter APIs for WebKit.
+class WebKitFlutterApis {
+  /// Constructs a [WebKitFlutterApis].
+  @visibleForTesting
+  WebKitFlutterApis({
+    BinaryMessenger? binaryMessenger,
+    InstanceManager? instanceManager,
+  }) : _binaryMessenger = binaryMessenger {
+    navigationDelegateFlutterApi = WKNavigationDelegateFlutterApiImpl(
+      instanceManager: instanceManager,
+    );
+  }
+
+  static WebKitFlutterApis _instance = WebKitFlutterApis();
+
+  /// Sets the global instance containing the Flutter Apis for the WebKit library.
+  @visibleForTesting
+  static set instance(WebKitFlutterApis instance) {
+    _instance = instance;
+  }
+
+  /// Global instance containing the Flutter Apis for the WebKit library.
+  static WebKitFlutterApis get instance {
+    return _instance;
+  }
+
+  final BinaryMessenger? _binaryMessenger;
+  bool _hasBeenSetUp = false;
+
+  /// Flutter Api for [WKNavigationDelegate].
+  @visibleForTesting
+  late final WKNavigationDelegateFlutterApiImpl navigationDelegateFlutterApi;
+
+  /// Ensures all the Flutter APIs have been set up to receive calls from native code.
+  void ensureSetUp() {
+    if (!_hasBeenSetUp) {
+      WKNavigationDelegateFlutterApi.setup(
+        navigationDelegateFlutterApi,
+        binaryMessenger: _binaryMessenger,
+      );
+      _hasBeenSetUp = true;
+    }
+  }
+}
+
 /// Host api implementation for [WKWebSiteDataStore].
 class WKWebsiteDataStoreHostApiImpl extends WKWebsiteDataStoreHostApi {
   /// Constructs a [WebsiteDataStoreHostApiImpl].
@@ -381,6 +427,47 @@ class WKNavigationDelegateHostApiImpl extends WKNavigationDelegateHostApi {
       await create(instanceId);
     }
   }
+
+  /// Calls [setDidFinishNavigation] with the ids of the provided object instances.
+  Future<void> setDidFinishNavigationFromInstance(
+    WKNavigationDelegate instance,
+    void Function(WKWebView, String?)? didFinishNavigation,
+  ) {
+    int? functionInstanceId;
+    if (didFinishNavigation != null) {
+      functionInstanceId = instanceManager.getInstanceId(didFinishNavigation) ??
+          instanceManager.tryAddInstance(didFinishNavigation)!;
+    }
+    return setDidFinishNavigation(
+      instanceManager.getInstanceId(instance)!,
+      functionInstanceId,
+    );
+  }
+}
+
+/// Flutter api implementation for [WKNavigationDelegate].
+class WKNavigationDelegateFlutterApiImpl
+    extends WKNavigationDelegateFlutterApi {
+  /// Constructs a [WKNavigationDelegateFlutterApiImpl].
+  WKNavigationDelegateFlutterApiImpl({InstanceManager? instanceManager}) {
+    this.instanceManager = instanceManager ?? InstanceManager.instance;
+  }
+
+  /// Maintains instances stored to communicate with native language objects.
+  late final InstanceManager instanceManager;
+
+  @override
+  void didFinishNavigation(
+    int functionInstanceId,
+    int webViewInstanceId,
+    String? url,
+  ) {
+    final void Function(
+      WKWebView webView,
+      String? url,
+    ) function = instanceManager.getInstance(functionInstanceId)!;
+    function(instanceManager.getInstance(webViewInstanceId)!, url);
+  }
 }
 
 /// Host api implementation for [WKWebView].