[webview_flutter_lwe] Fix "channel sent a message from native to Flutter on a non-platform thread" error

packages/webview_flutter_lwe/CHANGELOG.md

@@ -1,3 +1,7 @@
+## NEXT
+
+* Fix an issue where platform channel isn't called on the main thread.
+
 ## 0.3.4
 
 * Update lightweight web engine(1.3.3).

packages/webview_flutter_lwe/tizen/src/message_dispatcher.cc

@@ -0,0 +1,20 @@
+// Copyright 2025 Samsung Electronics Co., Ltd. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#include "message_dispatcher.h"
+
+#include <Ecore.h>
+
+MessageDispatcher::MessageDispatcher() { ecore_init(); }
+MessageDispatcher::~MessageDispatcher() { ecore_shutdown(); }
+
+void MessageDispatcher::dispatchTaskOnMainThread(std::function<void()>&& fn) {
+  ecore_main_loop_thread_safe_call_sync(
+      [](void* data) -> void* {
+        auto fn = static_cast<std::function<void()>*>(data);
+        if (fn) (*fn)();
+        return nullptr;
+      },
+      &fn);
+}

packages/webview_flutter_lwe/tizen/src/message_dispatcher.h

@@ -0,0 +1,18 @@
+// Copyright 2025 Samsung Electronics Co., Ltd. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+#ifndef FLUTTER_PLUGIN_MESSAGE_DISPATCHER_H_
+#define FLUTTER_PLUGIN_MESSAGE_DISPATCHER_H_
+
+#include <functional>
+
+class MessageDispatcher {
+ public:
+  MessageDispatcher();
+  ~MessageDispatcher();
+
+  void dispatchTaskOnMainThread(std::function<void()>&& fn);
+};
+
+#endif  // FLUTTER_PLUGIN_MESSAGE_DISPATCHER_H_

packages/webview_flutter_lwe/tizen/src/webview.cc

@@ -125,6 +125,8 @@ WebView::WebView(flutter::PluginRegistrar* registrar, int view_id,
 
   InitWebView();
 
+  dispatcher_ = std::make_unique<MessageDispatcher>();
+
   webview_channel_ = std::make_unique<FlMethodChannel>(
       GetPluginRegistrar()->messenger(), GetWebViewChannelName(),
       &flutter::StandardMethodCodec::GetInstance());
@@ -150,22 +152,32 @@ WebView::WebView(flutter::PluginRegistrar* registrar, int view_id,
       [this](LWE::WebContainer* container, const std::string& url) {
         flutter::EncodableMap args = {
             {flutter::EncodableValue("url"), flutter::EncodableValue(url)}};
-        navigation_delegate_channel_->InvokeMethod(
-            "onPageStarted", std::make_unique<flutter::EncodableValue>(args));
+
+        dispatcher_->dispatchTaskOnMainThread([this, &args]() {
+          navigation_delegate_channel_->InvokeMethod(
+              "onPageStarted", std::make_unique<flutter::EncodableValue>(args));
+        });
       });
   webview_instance_->RegisterOnPageLoadedHandler(
       [this](LWE::WebContainer* container, const std::string& url) {
         flutter::EncodableMap args = {
             {flutter::EncodableValue("url"), flutter::EncodableValue(url)}};
-        navigation_delegate_channel_->InvokeMethod(
-            "onPageFinished", std::make_unique<flutter::EncodableValue>(args));
+
+        dispatcher_->dispatchTaskOnMainThread([this, &args]() {
+          navigation_delegate_channel_->InvokeMethod(
+              "onPageFinished",
+              std::make_unique<flutter::EncodableValue>(args));
+        });
       });
   webview_instance_->RegisterOnProgressChangedHandler(
       [this](LWE::WebContainer* container, int progress) {
         flutter::EncodableMap args = {{flutter::EncodableValue("progress"),
                                        flutter::EncodableValue(progress)}};
-        navigation_delegate_channel_->InvokeMethod(
-            "onProgress", std::make_unique<flutter::EncodableValue>(args));
+
+        dispatcher_->dispatchTaskOnMainThread([this, &args]() {
+          navigation_delegate_channel_->InvokeMethod(
+              "onProgress", std::make_unique<flutter::EncodableValue>(args));
+        });
       });
   webview_instance_->RegisterOnReceivedErrorHandler(
       [this](LWE::WebContainer* container, LWE::ResourceError error) {
@@ -177,9 +189,12 @@ WebView::WebView(flutter::PluginRegistrar* registrar, int view_id,
             {flutter::EncodableValue("failingUrl"),
              flutter::EncodableValue(error.GetUrl())},
         };
-        navigation_delegate_channel_->InvokeMethod(
-            "onWebResourceError",
-            std::make_unique<flutter::EncodableValue>(args));
+
+        dispatcher_->dispatchTaskOnMainThread([this, &args]() {
+          navigation_delegate_channel_->InvokeMethod(
+              "onWebResourceError",
+              std::make_unique<flutter::EncodableValue>(args));
+        });
       });
   webview_instance_->RegisterShouldOverrideUrlLoadingHandler(
       [this](LWE::WebContainer* view, const std::string& url) -> bool {
@@ -191,10 +206,14 @@ WebView::WebView(flutter::PluginRegistrar* registrar, int view_id,
             {flutter::EncodableValue("isForMainFrame"),
              flutter::EncodableValue(true)},
         };
-        auto result = std::make_unique<NavigationRequestResult>(url, this);
-        navigation_delegate_channel_->InvokeMethod(
-            "navigationRequest",
-            std::make_unique<flutter::EncodableValue>(args), std::move(result));
+
+        dispatcher_->dispatchTaskOnMainThread([this, &args, url]() {
+          auto result = std::make_unique<NavigationRequestResult>(url, this);
+          navigation_delegate_channel_->InvokeMethod(
+              "navigationRequest",
+              std::make_unique<flutter::EncodableValue>(args),
+              std::move(result));
+        });
         return true;
       });
 }
@@ -212,9 +231,11 @@ void WebView::RegisterJavaScriptChannelName(const std::string& name) {
         {flutter::EncodableValue("channel"), flutter::EncodableValue(name)},
         {flutter::EncodableValue("message"), flutter::EncodableValue(message)},
     };
-    webview_channel_->InvokeMethod(
-        "javaScriptChannelMessage",
-        std::make_unique<flutter::EncodableValue>(args));
+    dispatcher_->dispatchTaskOnMainThread([this, &args]() {
+      webview_channel_->InvokeMethod(
+          "javaScriptChannelMessage",
+          std::make_unique<flutter::EncodableValue>(args));
+    });
     return "success";
   };
   webview_instance_->AddJavaScriptInterface(name, "postMessage", on_message);
@@ -622,7 +643,9 @@ void WebView::HandleWebViewMethodCall(const FlMethodCall& method_call,
           delete result;
         }
       };
+
       webview_instance_->EvaluateJavaScript(*javascript, on_result);
+
     } else {
       result->Error("Invalid argument", "The argument must be a string.");
     }

packages/webview_flutter_lwe/tizen/src/webview.h

@@ -17,6 +17,8 @@
 #include <mutex>
 #include <string>
 
+#include "message_dispatcher.h"
+
 typedef flutter::MethodCall<flutter::EncodableValue> FlMethodCall;
 typedef flutter::MethodResult<flutter::EncodableValue> FlMethodResult;
 typedef flutter::MethodChannel<flutter::EncodableValue> FlMethodChannel;
@@ -74,6 +76,7 @@ class WebView : public PlatformView {
   BufferUnit* rendered_surface_ = nullptr;
   bool is_mouse_lbutton_down_ = false;
   bool has_navigation_delegate_ = false;
+  std::unique_ptr<MessageDispatcher> dispatcher_;
   std::unique_ptr<FlMethodChannel> webview_channel_;
   std::unique_ptr<FlMethodChannel> navigation_delegate_channel_;
   std::unique_ptr<flutter::TextureVariant> texture_variant_;