Enabling local preview for screen sharing on Flutter windows will report an error

[liangzaifankun]

Version of the agora_rtc_engine

6.5.0

Platforms affected

• Android
• iOS
• macOS
• Windows
• Web

Steps to reproduce

engine = createAgoraRtcEngineEx();

await engine.initialize(RtcEngineContext(
  appId: appId,
  channelProfile: ChannelProfileType.channelProfileLiveBroadcasting,
));
await engine.setLogLevel(LogLevel.logLevelError);
engine.registerEventHandler(_rtcEngineEventHandler);

await engine.enableVideo();
await engine.setClientRole(role: ClientRoleType.clientRoleBroadcaster);
await engine
    .setScreenCaptureScenario(ScreenScenarioType.screenScenarioGaming);

await LastmileProbeTest();
isReadyPreview.value = true;

await engine.startPreview(
sourceType: VideoSourceType.videoSourceScreen);

AgoraVideoView(
controller: VideoViewController(
rtcEngine: logic.screenCallController.engine,
canvas: const VideoCanvas(
uid: 0,
sourceType: VideoSourceType.videoSourceScreen,
renderMode: RenderModeType.renderModeFit,
),
)),

Expected results

Normal operation

Actual results

[ERROR:flutter/runtime/dart_vm_initializer.cc(41)] Unhandled Exception: MissingPluginException(No implementation found for method createTextureRender on channel agora_rtc_ng/video_view_controller)
#0 MethodChannel._invokeMethod (package:flutter/src/services/platform_channel.dart:332:7)

#1 GlobalVideoViewControllerIO.createTextureRender (package:agora_rtc_engine/src/impl/platform/io/global_video_view_controller_platform_io.dart:87:9)

#2 VideoViewControllerBaseMixin.createTextureRender (package:agora_rtc_engine/src/impl/video_view_controller_impl.dart:146:9)

#3 VideoViewControllerBaseMixin.initializeRender (package:agora_rtc_engine/src/impl/video_view_controller_impl.dart:160:22)

#4 _VideoViewControllerInternal.initializeRender (package:agora_rtc_engine/src/impl/agora_video_view_impl.dart:269:5)

#5 _AgoraRtcRenderTextureState._initializeTexture (package:agora_rtc_engine/src/impl/agora_video_view_impl.dart:333:5)

#6 _AgoraRtcRenderTextureState._initialize (package:agora_rtc_engine/src/impl/agora_video_view_impl.dart:323:7)

Code sample

AgoraVideoView( controller: VideoViewController( rtcEngine: logic.screenCallController.engine, canvas: const VideoCanvas( uid: 0, sourceType: VideoSourceType.videoSourceScreen, renderMode: RenderModeType.renderModeFit, ), )),

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[liangzaifankun]

I used the desktop_multi_window plugin. The child window could run normally when opened for the first time, but not when opened for the second time

[peilinok]

@liangzaifankun It seems like the method_channel have not been ready yet when you create the child window, would you please provide a minimal project to reproduce this issue?

[liangzaifankun]

@liangzaifankun It seems like the method_channel have not been ready yet when you create the child window, would you please provide a minimal project to reproduce this issue?

I’ve found the root cause.

The issue was caused by my plugin registration logic in flutter_windows.cpp. I mistakenly put the AgoraRtcEnginePluginRegisterWithRegistrar call inside the if (!registered) block, which prevented the Agora plugin from being properly registered in child windows created by desktop_multi_window.

Here’s the corrected version of the code (notice that the Agora plugin is now registered outside the if (!registered) block):

DesktopMultiWindowSetWindowCreatedCallback([](void *controller) {
static bool registered = false;
auto *flutter_view_controller = reinterpret_cast<flutter::FlutterViewController *>(controller);
auto *registry = flutter_view_controller->engine();
if (!registered) {
ScreenRetrieverWindowsPluginCApiRegisterWithRegistrar(
registry->GetRegistrarForPlugin("ScreenRetrieverWindowsPluginCApi"));
AudioplayersWindowsPluginRegisterWithRegistrar(
registry->GetRegistrarForPlugin("AudioplayersWindowsPlugin"));
registered = true;
}

AgoraRtcEnginePluginRegisterWithRegistrar(
    registry->GetRegistrarForPlugin("AgoraRtcEnginePlugin"));
WindowManagerPluginRegisterWithRegistrar(
    registry->GetRegistrarForPlugin("WindowManagerPlugin"));

});
After this change, Agora SDK now works correctly in sub-windows. Hope this helps anyone who runs into similar problems.