postWebMessage method
Post a message to main frame. The embedded application can restrict the messages to a certain target origin. See HTML5 spec for how target origin can be used.
A target origin can be set as a wildcard ("*"). However this is not recommended.
NOTE for Android: This method should only be called if AndroidWebViewFeature.isFeatureSupported returns true
for AndroidWebViewFeature.POST_WEB_MESSAGE.
NOTE for iOS: This is implemented using Javascript.
Official Android API: https://developer.android.com/reference/androidx/webkit/WebViewCompat#postWebMessage(android.webkit.WebView,%20androidx.webkit.WebMessageCompat,%20android.net.Uri)
Implementation
Future<void> postWebMessage(
{required WebMessage message, Uri? targetOrigin}) async {
if (targetOrigin == null) {
targetOrigin = Uri.parse("");
}
Map<String, dynamic> args = <String, dynamic>{};
args.putIfAbsent('message', () => message.toMap());
args.putIfAbsent('targetOrigin', () => targetOrigin.toString());
await _channel.invokeMethod('postWebMessage', args);
}