fix: web build error

example/lib/examples/advanced/screen_sharing.dart

@@ -42,7 +42,11 @@ class _State extends State<ScreenSharing> {
         _addListeners();
         () async {
           await _engine.enableVideo();
-          await _engine.startPreview();
+          if (kIsWeb) {
+            await _engine.startScreenCapture(0);
+          } else {
+            await _engine.startPreview();
+          }
           await _engine.setChannelProfile(ChannelProfile.LiveBroadcasting);
           await _engine.setClientRole(ClientRole.Broadcaster);
           setState(() {
@@ -179,18 +183,21 @@ class _State extends State<ScreenSharing> {
             _renderVideo(),
           ],
         ),
-        Align(
-          alignment: Alignment.bottomRight,
-          child: Column(
-            mainAxisSize: MainAxisSize.min,
-            children: [
-              ElevatedButton(
-                onPressed: screenSharing ? _stopScreenShare : _startScreenShare,
-                child: Text('${screenSharing ? 'Stop' : 'Start'} screen share'),
-              ),
-            ],
-          ),
-        )
+        if (!kIsWeb)
+          Align(
+            alignment: Alignment.bottomRight,
+            child: Column(
+              mainAxisSize: MainAxisSize.min,
+              children: [
+                ElevatedButton(
+                  onPressed:
+                      screenSharing ? _stopScreenShare : _startScreenShare,
+                  child:
+                      Text('${screenSharing ? 'Stop' : 'Start'} screen share'),
+                ),
+              ],
+            ),
+          )
       ],
     );
   }
@@ -201,11 +208,12 @@ class _State extends State<ScreenSharing> {
       children: [
         Row(
           children: [
-            Expanded(
-                flex: 1,
-                child: kIsWeb
-                    ? RtcLocalView.SurfaceView()
-                    : RtcLocalView.TextureView()),
+            if (startPreview)
+              Expanded(
+                  flex: 1,
+                  child: kIsWeb
+                      ? RtcLocalView.SurfaceView()
+                      : RtcLocalView.TextureView()),
             if (screenSharing)
               Expanded(flex: 1, child: RtcLocalView.TextureView.screenShare()),
           ],

example/lib/examples/basic/join_channel_audio.dart

@@ -188,10 +188,11 @@ class _State extends State<JoinChannelAudio> {
                     child:
                         Text(enableSpeakerphone ? 'Speakerphone' : 'Earpiece'),
                   ),
-                  ElevatedButton(
-                    onPressed: this._switchEffect,
-                    child: Text('${playEffect ? 'Stop' : 'Play'} effect'),
-                  ),
+                  if (!kIsWeb)
+                    ElevatedButton(
+                      onPressed: this._switchEffect,
+                      child: Text('${playEffect ? 'Stop' : 'Play'} effect'),
+                    ),
                   Row(
                     mainAxisAlignment: MainAxisAlignment.end,
                     children: [

lib/rtc_engine.dart

@@ -2,4 +2,5 @@ export 'src/classes.dart';
 export 'src/enums.dart';
 export 'src/events.dart' hide RtcChannelEventHandler;
 export 'src/rtc_engine.dart' show RtcEngine;
-export 'src/rtc_engine_extension.dart';
+export 'src/rtc_engine_extension.dart'
+    if (dart.library.html) 'src/rtc_engine_extension_web.dart';

lib/src/rtc_engine.dart

@@ -2588,14 +2588,14 @@ class RtcEngine with RtcEngineInterface {
 
   @override
   Future<void> startScreenCaptureByDisplayId(int displayId,
-      Rectangle regionRect, ScreenCaptureParameters captureParams) {
+      [Rectangle? regionRect, ScreenCaptureParameters? captureParams]) {
     if (!kIsWeb && (Platform.isWindows || Platform.isMacOS)) {
       return _invokeMethod('callApi', {
         'apiType': _ApiTypeEngine.kEngineStartScreenCaptureByDisplayId.index,
         'params': jsonEncode({
           'displayId': displayId,
-          'regionRect': regionRect.toJson(),
-          'captureParams': captureParams.toJson(),
+          'regionRect': regionRect?.toJson(),
+          'captureParams': captureParams?.toJson(),
         }),
       });
     }
@@ -2604,14 +2604,14 @@ class RtcEngine with RtcEngineInterface {
 
   @override
   Future<void> startScreenCaptureByScreenRect(Rectangle screenRect,
-      Rectangle regionRect, ScreenCaptureParameters captureParams) {
+      [Rectangle? regionRect, ScreenCaptureParameters? captureParams]) {
     if (!kIsWeb && (Platform.isWindows || Platform.isMacOS)) {
       return _invokeMethod('callApi', {
         'apiType': _ApiTypeEngine.kEngineStartScreenCaptureByScreenRect.index,
         'params': jsonEncode({
           'screenRect': screenRect.toJson(),
-          'regionRect': regionRect.toJson(),
-          'captureParams': captureParams.toJson(),
+          'regionRect': regionRect?.toJson(),
+          'captureParams': captureParams?.toJson(),
         }),
       });
     }
@@ -2673,15 +2673,15 @@ class RtcEngine with RtcEngineInterface {
   }
 
   @override
-  Future<void> startScreenCapture(
-      int windowId, int captureFreq, Rect rect, int bitrate) {
+  Future<void> startScreenCapture(int windowId,
+      [int? captureFreq, Rect? rect, int? bitrate]) {
     if (kIsWeb || (Platform.isWindows || Platform.isMacOS)) {
       return _invokeMethod('callApi', {
         'apiType': _ApiTypeEngine.kEngineStartScreenCapture.index,
         'params': jsonEncode({
           'windowId': windowId,
           'captureFreq': captureFreq,
-          'rect': rect.toJson(),
+          'rect': rect?.toJson(),
           'bitrate': bitrate,
         }),
       });
@@ -4702,13 +4702,13 @@ mixin RtcStreamMessageInterface {
 /// TODO(doc)
 mixin RtcScreenSharingInterface {
   Future<void> startScreenCaptureByDisplayId(int displayId,
-      Rectangle regionRect, ScreenCaptureParameters captureParams);
+      [Rectangle? regionRect, ScreenCaptureParameters? captureParams]);
 
   Future<void> startScreenCaptureByScreenRect(Rectangle screenRect,
-      Rectangle regionRect, ScreenCaptureParameters captureParams);
+      [Rectangle? regionRect, ScreenCaptureParameters? captureParams]);
 
-  Future<void> startScreenCaptureByWindowId(int windowId, Rectangle regionRect,
-      ScreenCaptureParameters captureParams);
+  Future<void> startScreenCaptureByWindowId(int windowId,
+      [Rectangle? regionRect, ScreenCaptureParameters? captureParams]);
 
   Future<void> setScreenCaptureContentHint(VideoContentHint contentHint);
 
@@ -4719,6 +4719,6 @@ mixin RtcScreenSharingInterface {
 
   Future<void> stopScreenCapture();
 
-  Future<void> startScreenCapture(
-      int windowId, int captureFreq, Rect rect, int bitrate);
+  Future<void> startScreenCapture(int windowId,
+      [int? captureFreq, Rect? rect, int? bitrate]);
 }

lib/src/rtc_engine_extension_web.dart

@@ -0,0 +1,23 @@
+import 'package:flutter/services.dart';
+
+import 'enums.dart';
+import 'rtc_engine.dart';
+
+/// Extension for RtcEngine
+extension RtcEngineExtension on RtcEngine {
+  /// Get the actual absolute path of the asset through the relative path of the asset
+  ///
+  /// - [assetPath] The resource path configured in the `flutter` -> `assets` field of pubspec.yaml, for example: assets/Sound_Horizon.mp3
+  /// - Returns the actual absolute path of the asset
+  Future<String?> getAssetAbsolutePath(String assetPath) {
+    throw PlatformException(code: ErrorCode.NotSupported.toString());
+  }
+
+  List<dynamic> enumerateDisplays() {
+    throw PlatformException(code: ErrorCode.NotSupported.toString());
+  }
+
+  List<dynamic> enumerateWindows() {
+    throw PlatformException(code: ErrorCode.NotSupported.toString());
+  }
+}