[webview_flutter_wkwebview] Adds the isInspectable to WebKitWebViewController. (#3984)

Fixes: flutter/flutter#126899

Starting from iOS version 16.4, it is now possible to change the value of the isInspectable property in WKWebView.

https://developer.apple.com/documentation/webkit/wkwebview/4111163-isinspectable

Since iOS 16.4, the Web Inspector feature is disabled by default. 
Therefore, to use Web Inspector, need to change the value of isInspectable.

Here is a blog post from WebKit that discusses this
https://webkit.org/blog/13936/enabling-the-inspection-of-web-content-in-apps/

Apple Developer Forums thread (iOS 16.4 webview can not debug in safari web inspector) 
https://developer.apple.com/forums/thread/727049

Author: GwonHyeok

packages/webview_flutter/webview_flutter_wkwebview/CHANGELOG.md

@@ -1,3 +1,8 @@
+## 3.6.0
+
+* Adds support to enable debugging of web contents on the latest versions of WebKit. See
+  `WebKitWebViewController.setInspectable`.
+  
 ## 3.5.0
 
 * Adds support to limit navigation to pages within the app’s domain. See

packages/webview_flutter/webview_flutter_wkwebview/example/ios/RunnerTests/FWFWebViewHostApiTests.m

@@ -464,4 +464,20 @@ - (void)testContentInsetsSumAlwaysZeroAfterSetFrame {
   XCTAssertTrue(feq(webView.scrollView.contentInset.bottom, -insetToAdjust.bottom));
   XCTAssertTrue(CGRectEqualToRect(webView.frame, CGRectMake(0, 0, 300, 100)));
 }
+
+- (void)testSetInspectable API_AVAILABLE(ios(16.4), macos(13.3), tvos(16.4)) {
+  FWFWebView *mockWebView = OCMClassMock([FWFWebView class]);
+
+  FWFInstanceManager *instanceManager = [[FWFInstanceManager alloc] init];
+  [instanceManager addDartCreatedInstance:mockWebView withIdentifier:0];
+
+  FWFWebViewHostApiImpl *hostAPI = [[FWFWebViewHostApiImpl alloc]
+      initWithBinaryMessenger:OCMProtocolMock(@protocol(FlutterBinaryMessenger))
+              instanceManager:instanceManager];
+
+  FlutterError *error;
+  [hostAPI setInspectableForWebViewWithIdentifier:@0 inspectable:@YES error:&error];
+  OCMVerify([mockWebView setInspectable:YES]);
+  XCTAssertNil(error);
+}
 @end

packages/webview_flutter/webview_flutter_wkwebview/ios/Classes/FWFGeneratedWebKitApis.h

@@ -751,6 +751,9 @@ NSObject<FlutterMessageCodec> *FWFWKWebViewHostApiGetCodec(void);
                                   javaScriptString:(NSString *)javaScriptString
                                         completion:(void (^)(id _Nullable,
                                                              FlutterError *_Nullable))completion;
+- (void)setInspectableForWebViewWithIdentifier:(NSNumber *)identifier
+                                   inspectable:(NSNumber *)inspectable
+                                         error:(FlutterError *_Nullable *_Nonnull)error;
 @end
 
 extern void FWFWKWebViewHostApiSetup(id<FlutterBinaryMessenger> binaryMessenger,

packages/webview_flutter/webview_flutter_wkwebview/ios/Classes/FWFGeneratedWebKitApis.m

@@ -2481,6 +2481,31 @@ void FWFWKWebViewHostApiSetup(id<FlutterBinaryMessenger> binaryMessenger,
       [channel setMessageHandler:nil];
     }
   }
+  {
+    FlutterBasicMessageChannel *channel = [[FlutterBasicMessageChannel alloc]
+           initWithName:@"dev.flutter.pigeon.WKWebViewHostApi.setInspectable"
+        binaryMessenger:binaryMessenger
+                  codec:FWFWKWebViewHostApiGetCodec()];
+    if (api) {
+      NSCAssert([api respondsToSelector:@selector(setInspectableForWebViewWithIdentifier:
+                                                                             inspectable:error:)],
+                @"FWFWKWebViewHostApi api (%@) doesn't respond to "
+                @"@selector(setInspectableForWebViewWithIdentifier:inspectable:error:)",
+                api);
+      [channel setMessageHandler:^(id _Nullable message, FlutterReply callback) {
+        NSArray *args = message;
+        NSNumber *arg_identifier = GetNullableObjectAtIndex(args, 0);
+        NSNumber *arg_inspectable = GetNullableObjectAtIndex(args, 1);
+        FlutterError *error;
+        [api setInspectableForWebViewWithIdentifier:arg_identifier
+                                        inspectable:arg_inspectable
+                                              error:&error];
+        callback(wrapResult(nil, error));
+      }];
+    } else {
+      [channel setMessageHandler:nil];
+    }
+  }
 }
 NSObject<FlutterMessageCodec> *FWFWKUIDelegateHostApiGetCodec(void) {
   static FlutterStandardMessageCodec *sSharedObject = nil;

packages/webview_flutter/webview_flutter_wkwebview/ios/Classes/FWFWebViewHostApi.m

@@ -197,6 +197,18 @@ - (void)evaluateJavaScriptForWebViewWithIdentifier:(nonnull NSNumber *)identifie
        }];
 }
 
+- (void)setInspectableForWebViewWithIdentifier:(NSNumber *)identifier
+                                   inspectable:(NSNumber *)inspectable
+                                         error:(FlutterError *_Nullable *_Nonnull)error {
+  if (@available(macOS 13.3, iOS 16.4, tvOS 16.4, *)) {
+    [[self webViewForIdentifier:identifier] setInspectable:inspectable.boolValue];
+  } else {
+    *error = [FlutterError errorWithCode:@"FWFUnsupportedVersionError"
+                                 message:@"setInspectable is only supported on versions 16.4+."
+                                 details:nil];
+  }
+}
+
 - (void)goBackForWebViewWithIdentifier:(nonnull NSNumber *)identifier
                                  error:(FlutterError *_Nullable __autoreleasing *_Nonnull)error {
   [[self webViewForIdentifier:identifier] goBack];

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

@@ -675,6 +675,7 @@ class ObjectOrIdentifier {
 
 class _WKWebsiteDataStoreHostApiCodec extends StandardMessageCodec {
   const _WKWebsiteDataStoreHostApiCodec();
+
   @override
   void writeValue(WriteBuffer buffer, Object? value) {
     if (value is WKWebsiteDataTypeEnumData) {
@@ -961,6 +962,7 @@ class UIScrollViewHostApi {
 
 class _WKWebViewConfigurationHostApiCodec extends StandardMessageCodec {
   const _WKWebViewConfigurationHostApiCodec();
+
   @override
   void writeValue(WriteBuffer buffer, Object? value) {
     if (value is WKAudiovisualMediaTypeEnumData) {
@@ -1150,6 +1152,7 @@ abstract class WKWebViewConfigurationFlutterApi {
 
 class _WKUserContentControllerHostApiCodec extends StandardMessageCodec {
   const _WKUserContentControllerHostApiCodec();
+
   @override
   void writeValue(WriteBuffer buffer, Object? value) {
     if (value is WKUserScriptData) {
@@ -1435,6 +1438,7 @@ class WKScriptMessageHandlerHostApi {
 
 class _WKScriptMessageHandlerFlutterApiCodec extends StandardMessageCodec {
   const _WKScriptMessageHandlerFlutterApiCodec();
+
   @override
   void writeValue(WriteBuffer buffer, Object? value) {
     if (value is WKScriptMessageData) {
@@ -1537,6 +1541,7 @@ class WKNavigationDelegateHostApi {
 
 class _WKNavigationDelegateFlutterApiCodec extends StandardMessageCodec {
   const _WKNavigationDelegateFlutterApiCodec();
+
   @override
   void writeValue(WriteBuffer buffer, Object? value) {
     if (value is NSErrorData) {
@@ -1768,6 +1773,7 @@ abstract class WKNavigationDelegateFlutterApi {
 
 class _NSObjectHostApiCodec extends StandardMessageCodec {
   const _NSObjectHostApiCodec();
+
   @override
   void writeValue(WriteBuffer buffer, Object? value) {
     if (value is NSKeyValueObservingOptionsEnumData) {
@@ -1881,6 +1887,7 @@ class NSObjectHostApi {
 
 class _NSObjectFlutterApiCodec extends StandardMessageCodec {
   const _NSObjectFlutterApiCodec();
+
   @override
   void writeValue(WriteBuffer buffer, Object? value) {
     if (value is NSKeyValueChangeKeyEnumData) {
@@ -1982,6 +1989,7 @@ abstract class NSObjectFlutterApi {
 
 class _WKWebViewHostApiCodec extends StandardMessageCodec {
   const _WKWebViewHostApiCodec();
+
   @override
   void writeValue(WriteBuffer buffer, Object? value) {
     if (value is NSErrorData) {
@@ -2527,6 +2535,28 @@ class WKWebViewHostApi {
       return replyList[0];
     }
   }
+
+  Future<void> setInspectable(int arg_identifier, bool arg_inspectable) async {
+    final BasicMessageChannel<Object?> channel = BasicMessageChannel<Object?>(
+        'dev.flutter.pigeon.WKWebViewHostApi.setInspectable', codec,
+        binaryMessenger: _binaryMessenger);
+    final List<Object?>? replyList = await channel
+        .send(<Object?>[arg_identifier, arg_inspectable]) as List<Object?>?;
+    if (replyList == null) {
+      throw PlatformException(
+        code: 'channel-error',
+        message: 'Unable to establish connection on channel.',
+      );
+    } else if (replyList.length > 1) {
+      throw PlatformException(
+        code: replyList[0]! as String,
+        message: replyList[1] as String?,
+        details: replyList[2],
+      );
+    } else {
+      return;
+    }
+  }
 }
 
 /// Mirror of WKUIDelegate.
@@ -2567,6 +2597,7 @@ class WKUIDelegateHostApi {
 
 class _WKUIDelegateFlutterApiCodec extends StandardMessageCodec {
   const _WKUIDelegateFlutterApiCodec();
+
   @override
   void writeValue(WriteBuffer buffer, Object? value) {
     if (value is NSUrlRequestData) {
@@ -2703,6 +2734,7 @@ abstract class WKUIDelegateFlutterApi {
 
 class _WKHttpCookieStoreHostApiCodec extends StandardMessageCodec {
   const _WKHttpCookieStoreHostApiCodec();
+
   @override
   void writeValue(WriteBuffer buffer, Object? value) {
     if (value is NSHttpCookieData) {

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

@@ -1107,6 +1107,24 @@ class WKWebView extends UIView {
     );
   }
 
+  /// Enables debugging of web contents (HTML / CSS / JavaScript) in the
+  /// underlying WebView.
+  ///
+  /// This flag can be enabled in order to facilitate debugging of web layouts
+  /// and JavaScript code running inside WebViews. Please refer to [WKWebView](https://developer.apple.com/documentation/webkit/wkwebview?language=objc).
+  /// documentation for the debugging guide.
+  ///
+  /// Starting from macOS version 13.3, iOS version 16.4, and tvOS version 16.4,
+  /// the default value is set to false.
+  ///
+  /// Defaults to true in previous versions.
+  Future<void> setInspectable(bool inspectable) {
+    return _webViewApi.setInspectableForInstances(
+      this,
+      inspectable,
+    );
+  }
+
   @override
   WKWebView copy() {
     return WKWebView.detached(

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

@@ -1067,6 +1067,17 @@ class WKWebViewHostApiImpl extends WKWebViewHostApi {
     }
   }
 
+  /// Calls [setInspectable] with the ids of the provided object instances.
+  Future<void> setInspectableForInstances(
+    WKWebView instance,
+    bool inspectable,
+  ) async {
+    return setInspectable(
+      instanceManager.getIdentifier(instance)!,
+      inspectable,
+    );
+  }
+
   /// Calls [setNavigationDelegate] with the ids of the provided object instances.
   Future<void> setNavigationDelegateForInstances(
     WKWebView instance,

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

@@ -544,6 +544,18 @@ class WebKitWebViewController extends PlatformWebViewController {
   ) async {
     _onPermissionRequestCallback = onPermissionRequest;
   }
+
+  /// Whether to enable tools for debugging the current WKWebView content.
+  ///
+  /// It needs to be activated in each WKWebView where you want to enable it.
+  ///
+  /// Starting from macOS version 13.3, iOS version 16.4, and tvOS version 16.4,
+  /// the default value is set to false.
+  ///
+  /// Defaults to true in previous versions.
+  Future<void> setInspectable(bool inspectable) {
+    return _webView.setInspectable(inspectable);
+  }
 }
 
 /// An implementation of [JavaScriptChannelParams] with the WebKit api.

packages/webview_flutter/webview_flutter_wkwebview/pigeons/web_kit.dart

@@ -694,6 +694,9 @@ abstract class WKWebViewHostApi {
   @ObjCSelector('evaluateJavaScriptForWebViewWithIdentifier:javaScriptString:')
   @async
   Object? evaluateJavaScript(int identifier, String javaScriptString);
+
+  @ObjCSelector('setInspectableForWebViewWithIdentifier:inspectable:')
+  void setInspectable(int identifier, bool inspectable);
 }
 
 /// Mirror of WKUIDelegate.