Compatible with Android 10 and below WebViewFeature.WEB_MESSAGE_LISTENER is false, receive postMessage message

flutter_inappwebview/pubspec.yaml

@@ -19,8 +19,10 @@ dependencies:
   flutter:
     sdk: flutter
   flutter_inappwebview_platform_interface: ^1.0.10
-  flutter_inappwebview_android: ^1.0.12
-  flutter_inappwebview_ios: ^1.0.13
+  flutter_inappwebview_android:
+    path: ../flutter_inappwebview_android
+  flutter_inappwebview_ios:
+    path: ../flutter_inappwebview_ios
   flutter_inappwebview_macos: ^1.0.11
   flutter_inappwebview_web: ^1.0.8
 

flutter_inappwebview_android/android/src/main/java/com/pichillilorenzo/flutter_inappwebview_android/webview/WebViewChannelDelegate.java

@@ -635,16 +635,12 @@ public void onReceiveValue(Boolean value) {
         if (webView != null) {
           Map<String, Object> webMessageListenerMap = (Map<String, Object>) call.argument("webMessageListener");
           WebMessageListener webMessageListener = WebMessageListener.fromMap(webView, webView.getPlugin().messenger, webMessageListenerMap);
-          if (webView instanceof InAppWebView && WebViewFeature.isFeatureSupported(WebViewFeature.WEB_MESSAGE_LISTENER)) {
             try {
               webView.addWebMessageListener(webMessageListener);
               result.success(true);
             } catch (Exception e) {
               result.error(LOG_TAG, e.getMessage(), null);
             }
-          } else {
-            result.success(true);
-          }
         } else {
           result.success(true);
         }

flutter_inappwebview_android/android/src/main/java/com/pichillilorenzo/flutter_inappwebview_android/webview/in_app_webview/InAppWebView.java

@@ -1895,6 +1895,8 @@ public void addWebMessageListener(@NonNull WebMessageListener webMessageListener
     if (WebViewFeature.isFeatureSupported(WebViewFeature.WEB_MESSAGE_LISTENER)) {
       WebViewCompat.addWebMessageListener(this, webMessageListener.jsObjectName, webMessageListener.allowedOriginRules, webMessageListener.listener);
       webMessageListeners.add(webMessageListener);
+    } else {
+      addJavascriptInterface(webMessageListener, webMessageListener.jsObjectName);
     }
   }
 

flutter_inappwebview_android/android/src/main/java/com/pichillilorenzo/flutter_inappwebview_android/webview/web_message/WebMessageListener.java

@@ -1,7 +1,10 @@
 package com.pichillilorenzo.flutter_inappwebview_android.webview.web_message;
 
 import android.net.Uri;
+import android.os.Handler;
+import android.os.Looper;
 import android.text.TextUtils;
+import android.webkit.JavascriptInterface;
 import android.webkit.WebView;
 
 import androidx.annotation.NonNull;
@@ -21,6 +24,7 @@
 import com.pichillilorenzo.flutter_inappwebview_android.webview.in_app_webview.InAppWebView;
 
 import java.util.ArrayList;
+import java.util.HashMap;
 import java.util.HashSet;
 import java.util.List;
 import java.util.Map;
@@ -171,6 +175,23 @@ public void assertOriginRulesValid() throws Exception {
     }
   }
 
+    // Suppressing unused warning as this is invoked from JavaScript.
+    @SuppressWarnings("unused")
+    @JavascriptInterface
+    public void postMessage(@NonNull final String message) {
+      System.out.println("postMessage " + message);
+    Map<String, Object> map = new HashMap<>();
+      map.put("data", message);
+      map.put("type", WebMessageCompat.TYPE_STRING);
+      WebMessageCompatExt webMessage = WebMessageCompatExt.fromMap(map);
+      if (channelDelegate != null) {
+        Handler mainHandler = new Handler(Looper.getMainLooper());
+        mainHandler.post(() -> channelDelegate.onPostMessage(webMessage,
+				null,
+				false));
+      }
+    }
+
   public void postMessageForInAppWebView(WebMessageCompatExt message, @NonNull MethodChannel.Result result) {
     if (replyProxy != null && WebViewFeature.isFeatureSupported(WebViewFeature.WEB_MESSAGE_LISTENER)) {
       Object data = message.getData();

flutter_inappwebview_ios/ios/Classes/InAppWebView/InAppWebView.swift

@@ -1428,8 +1428,9 @@ public class InAppWebView: WKWebView, UIScrollViewDelegate, WKUIDelegate,
             completionHandler(nil)
         }
     }
-
-    public override func evaluateJavaScript(_ javaScriptString: String, completionHandler: ((Any?, Error?) -> Void)? = nil) {
+
+#if compiler(>=6.0)
+    public override func evaluateJavaScript(_ javaScriptString: String, completionHandler: (@MainActor @Sendable (Any?, (any Error)?) -> Void)? = nil) {
         if let applePayAPIEnabled = settings?.applePayAPIEnabled, applePayAPIEnabled {
             if let completionHandler = completionHandler {
                 completionHandler(nil, nil)
@@ -1438,6 +1439,16 @@ public class InAppWebView: WKWebView, UIScrollViewDelegate, WKUIDelegate,
         }
         super.evaluateJavaScript(javaScriptString, completionHandler: completionHandler)
     }
+#else
+    public override func evaluateJavaScript(_ javaScriptString: String, completionHandler: ((Any?, Error?) -> Void)? = nil) {                if let applePayAPIEnabled = settings?.applePayAPIEnabled, applePayAPIEnabled {
+            if let completionHandler = completionHandler {
+                completionHandler(nil, nil)
+            }
+            return
+        }
+        super.evaluateJavaScript(javaScriptString, completionHandler: completionHandler)
+    }
+#endif
 
     @available(iOS 14.0, *)
     public func evaluateJavaScript(_ javaScript: String, frame: WKFrameInfo? = nil, contentWorld: WKContentWorld, completionHandler: ((Result<Any, Error>) -> Void)? = nil) {

flutter_inappwebview_ios/ios/flutter_inappwebview_ios.podspec

@@ -30,7 +30,7 @@ A new Flutter plugin.
   s.swift_version = '5.0'
 
   s.platforms = { :ios => '11.0' }
-  s.dependency 'OrderedSet', '~>5.0'
+  s.dependency 'OrderedSet', '~>6.0.3'
 
   s.default_subspec = 'Core'