[webview_flutter_wkwebview] Implementation of PlatformNavigationDelegate for WebKit

packages/webview_flutter/webview_flutter_wkwebview/lib/src/v4/src/webkit_navigation_delegate.dart

@@ -0,0 +1,161 @@
+// 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 'dart:async';
+
+import 'package:flutter/foundation.dart';
+import 'package:flutter/material.dart';
+import 'package:webview_flutter_platform_interface/v4/webview_flutter_platform_interface.dart';
+
+import '../../foundation/foundation.dart';
+import '../../web_kit/web_kit.dart';
+import 'webkit_proxy.dart';
+
+/// An implementation of [WebResourceError] with the WebKit API.
+class WebKitWebResourceError extends WebResourceError {
+  WebKitWebResourceError._(this._nsError)
+      : super(
+          errorCode: _nsError.code,
+          description: _nsError.localizedDescription,
+          errorType: _toWebResourceErrorType(_nsError.code),
+        );
+
+  static WebResourceErrorType? _toWebResourceErrorType(int code) {
+    switch (code) {
+      case WKErrorCode.unknown:
+        return WebResourceErrorType.unknown;
+      case WKErrorCode.webContentProcessTerminated:
+        return WebResourceErrorType.webContentProcessTerminated;
+      case WKErrorCode.webViewInvalidated:
+        return WebResourceErrorType.webViewInvalidated;
+      case WKErrorCode.javaScriptExceptionOccurred:
+        return WebResourceErrorType.javaScriptExceptionOccurred;
+      case WKErrorCode.javaScriptResultTypeIsUnsupported:
+        return WebResourceErrorType.javaScriptResultTypeIsUnsupported;
+    }
+
+    return null;
+  }
+
+  /// A string representing the domain of the error.
+  String? get domain => _nsError.domain;
+
+  final NSError _nsError;
+}
+
+/// An implementation of [PlatformNavigationDelegate] with the WebKit API.
+class WebKitNavigationDelegate extends PlatformNavigationDelegate {
+  /// Constructs a [WebKitNavigationDelegate].
+  WebKitNavigationDelegate(
+    super.params, {
+    @visibleForTesting WebKitProxy webKitProxy = const WebKitProxy(),
+  }) : super.implementation() {
+    final WeakReference<WebKitNavigationDelegate> weakThis =
+        WeakReference<WebKitNavigationDelegate>(this);
+    navigationDelegate = webKitProxy.createNavigationDelegate(
+      didFinishNavigation: (WKWebView webView, String? url) {
+        if (weakThis.target?._onPageFinished != null) {
+          weakThis.target!._onPageFinished!(url ?? '');
+        }
+      },
+      didStartProvisionalNavigation: (WKWebView webView, String? url) {
+        if (weakThis.target?._onPageStarted != null) {
+          weakThis.target!._onPageStarted!(url ?? '');
+        }
+      },
+      decidePolicyForNavigationAction: (
+        WKWebView webView,
+        WKNavigationAction action,
+      ) async {
+        if (weakThis.target?._onNavigationRequest != null) {
+          final bool allow = await weakThis.target!._onNavigationRequest!(
+            url: action.request.url,
+            isForMainFrame: action.targetFrame.isMainFrame,
+          );
+          return allow
+              ? WKNavigationActionPolicy.allow
+              : WKNavigationActionPolicy.cancel;
+        }
+        return WKNavigationActionPolicy.allow;
+      },
+      didFailNavigation: (WKWebView webView, NSError error) {
+        if (weakThis.target?._onWebResourceError != null) {
+          weakThis.target!._onWebResourceError!(
+            WebKitWebResourceError._(error),
+          );
+        }
+      },
+      didFailProvisionalNavigation: (WKWebView webView, NSError error) {
+        if (weakThis.target?._onWebResourceError != null) {
+          weakThis.target!._onWebResourceError!(
+            WebKitWebResourceError._(error),
+          );
+        }
+      },
+      webViewWebContentProcessDidTerminate: (WKWebView webView) {
+        if (weakThis.target?._onWebResourceError != null) {
+          weakThis.target!._onWebResourceError!(
+            WebKitWebResourceError._(
+              const NSError(
+                code: WKErrorCode.webContentProcessTerminated,
+                // Value from https://developer.apple.com/documentation/webkit/wkerrordomain?language=objc.
+                domain: 'WKErrorDomain',
+                localizedDescription: '',
+              ),
+            ),
+          );
+        }
+      },
+    );
+  }
+
+  // Used to set `WKWebView.setNavigationDelegate` in `WebKitWebViewController`.
+  /// WebKit class that handles navigation changes and tracking navigation
+  /// requests.
+  late final WKNavigationDelegate navigationDelegate;
+
+  void Function(String url)? _onPageFinished;
+  void Function(String url)? _onPageStarted;
+  void Function(int progress)? _onProgress;
+  void Function(WebResourceError error)? _onWebResourceError;
+  FutureOr<bool> Function({required String url, required bool isForMainFrame})?
+      _onNavigationRequest;
+
+  // `WKWebView` in `WebKitWebViewController` uses this to track loading
+  // progress. This can't be done with `WKNavigationDelegate`.
+  /// Callback method that receives progress of a loading page.
+  void Function(int progress)? get onProgress => _onProgress;
+
+  @override
+  Future<void> setOnPageFinished(
+    void Function(String url) onPageFinished,
+  ) async {
+    _onPageFinished = onPageFinished;
+  }
+
+  @override
+  Future<void> setOnPageStarted(void Function(String url) onPageStarted) async {
+    _onPageStarted = onPageStarted;
+  }
+
+  @override
+  Future<void> setOnProgress(void Function(int progress) onProgress) async {
+    _onProgress = onProgress;
+  }
+
+  @override
+  Future<void> setOnWebResourceError(
+    void Function(WebResourceError error) onWebResourceError,
+  ) async {
+    _onWebResourceError = onWebResourceError;
+  }
+
+  @override
+  Future<void> setOnNavigationRequest(
+    FutureOr<bool> Function({required String url, required bool isForMainFrame})
+        onNavigationRequest,
+  ) async {
+    _onNavigationRequest = onNavigationRequest;
+  }
+}

packages/webview_flutter/webview_flutter_wkwebview/lib/src/v4/src/webkit_proxy.dart

@@ -20,6 +20,7 @@ class WebKitProxy {
     this.createWebView = WKWebView.new,
     this.createWebViewConfiguration = WKWebViewConfiguration.new,
     this.createScriptMessageHandler = WKScriptMessageHandler.new,
+    this.createNavigationDelegate = WKNavigationDelegate.new,
   });
 
   /// Constructs a [WKWebView].
@@ -44,4 +45,20 @@ class WebKitProxy {
     )
         didReceiveScriptMessage,
   }) createScriptMessageHandler;
+
+  /// Constructs a [WKNavigationDelegate].
+  final WKNavigationDelegate Function({
+    void Function(WKWebView webView, String? url)? didFinishNavigation,
+    void Function(WKWebView webView, String? url)?
+        didStartProvisionalNavigation,
+    Future<WKNavigationActionPolicy> Function(
+      WKWebView webView,
+      WKNavigationAction navigationAction,
+    )?
+        decidePolicyForNavigationAction,
+    void Function(WKWebView webView, NSError error)? didFailNavigation,
+    void Function(WKWebView webView, NSError error)?
+        didFailProvisionalNavigation,
+    void Function(WKWebView webView)? webViewWebContentProcessDidTerminate,
+  }) createNavigationDelegate;
 }

packages/webview_flutter/webview_flutter_wkwebview/lib/src/v4/src/webkit_webview_controller.dart

@@ -13,6 +13,7 @@ import 'package:webview_flutter_platform_interface/v4/webview_flutter_platform_i
 import '../../common/weak_reference_utils.dart';
 import '../../foundation/foundation.dart';
 import '../../web_kit/web_kit.dart';
+import 'webkit_navigation_delegate.dart';
 import 'webkit_proxy.dart';
 
 /// Object specifying creation parameters for a [WebKitWebViewController].
@@ -46,8 +47,29 @@ class WebKitWebViewController extends PlatformWebViewController {
             ? params
             : WebKitWebViewControllerCreationParams
                 .fromPlatformWebViewControllerCreationParams(params)) {
+    final WeakReference<WebKitWebViewController> weakThis =
+        WeakReference<WebKitWebViewController>(this);
     _webView = webKitProxy.createWebView(
-        (params as WebKitWebViewControllerCreationParams)._configuration);
+      (params as WebKitWebViewControllerCreationParams)._configuration,
+      observeValue: (
+        String keyPath,
+        NSObject object,
+        Map<NSKeyValueChangeKey, Object?> change,
+      ) {
+        if (weakThis.target?._onProgress != null) {
+          final double progress =
+              change[NSKeyValueChangeKey.newValue]! as double;
+          weakThis.target!._onProgress!((progress * 100).round());
+        }
+      },
+    );
+    _webView.addObserver(
+      _webView,
+      keyPath: 'estimatedProgress',
+      options: <NSKeyValueObservingOptions>{
+        NSKeyValueObservingOptions.newValue,
+      },
+    );
   }
 
   late final WKWebView _webView;
@@ -56,6 +78,7 @@ class WebKitWebViewController extends PlatformWebViewController {
       <String, WebKitJavaScriptChannelParams>{};
 
   bool _zoomEnabled = true;
+  void Function(int progress)? _onProgress;
 
   @override
   Future<void> loadFile(String absoluteFilePath) {
@@ -270,6 +293,14 @@ class WebKitWebViewController extends PlatformWebViewController {
     }
   }
 
+  @override
+  Future<void> setPlatformNavigationDelegate(
+    covariant WebKitNavigationDelegate handler,
+  ) {
+    _onProgress = handler.onProgress;
+    return _webView.setNavigationDelegate(handler.navigationDelegate);
+  }
+
   Future<void> _disableZoom() {
     const WKUserScript userScript = WKUserScript(
       "var meta = document.createElement('meta');\n"

packages/webview_flutter/webview_flutter_wkwebview/lib/src/v4/src/webkit_webview_platform.dart

@@ -4,14 +4,22 @@
 
 import 'package:webview_flutter_platform_interface/v4/webview_flutter_platform_interface.dart';
 
+import 'webkit_navigation_delegate.dart';
 import 'webkit_webview_controller.dart';
 
-/// Implementation of [WebViewPlatform] using the WebKit Api.
+/// Implementation of [WebViewPlatform] using the WebKit API.
 class WebKitWebViewPlatform extends WebViewPlatform {
   @override
   WebKitWebViewController createPlatformWebViewController(
     PlatformWebViewControllerCreationParams params,
   ) {
     return WebKitWebViewController(params);
   }
+
+  @override
+  WebKitNavigationDelegate createPlatformNavigationDelegate(
+    PlatformNavigationDelegateCreationParams params,
+  ) {
+    return WebKitNavigationDelegate(params);
+  }
 }

packages/webview_flutter/webview_flutter_wkwebview/lib/src/v4/webview_flutter_wkwebview.dart

@@ -4,4 +4,6 @@
 
 library webview_flutter_wkwebview;
 
+export 'src/webkit_navigation_delegate.dart';
+export 'src/webkit_webview_controller.dart';
 export 'src/webkit_webview_controller.dart';