Android's WebView has much stricter security policies than iOS's WKWebView when it comes to dynamic iframe creation. When JavaScript tries to create an iframe on-the-fly and inject it into the DOM, Android's WebView often blocks it silently. You'll see errors like:
"Kommunicate is not defined"
"Cannot access frame"
The iframe simply doesn't appear
JavaScript that should run inside the iframe never executes
Meanwhile, on iOS, the exact same code works flawlessly. Maddening, right?
1. JavaScript Interface Restrictions
Android WebView has tighter restrictions on JavaScript execution, especially when it involves:
Creating new window contexts (iframes)
Cross-origin communication
Dynamic script injection
DOM manipulation that creates new browsing contexts
2. Mixed Content Blocking
Even if your main content is HTTPS, if the iframe tries to load any HTTP resources, Android blocks it more aggressively than iOS.
3. WebView Settings That Matter
Android WebView has specific settings that need to be enabled for dynamic iframe creation to work. Missing even one can break everything.
Solution 1: Configure WebView Settings Properly
Here's the configuration that usually fixes it:
dart
import 'package:webview_flutter/webview_flutter.dart';
import 'package:webview_flutter_android/webview_flutter_android.dart';
class ChatWebView extends StatefulWidget {
@override
_ChatWebViewState createState() => _ChatWebViewState();
}
class _ChatWebViewState extends State<ChatWebView> {
late final WebViewController controller;
@override
void initState() {
super.initState();
controller = WebViewController()
..setJavaScriptMode(JavaScriptMode.unrestricted)
..setBackgroundColor(Colors.transparent);
// This is the crucial part for Android
if (controller.platform is AndroidWebViewController) {
final androidController = controller.platform as AndroidWebViewController;
androidController
..setMediaPlaybackRequiresUserGesture(false)
..setOnShowFileSelector((params) async {
// Handle file selection if needed
return [];
});
// Enable debugging to see what's happening
AndroidWebViewController.enableDebugging(true);
}
_loadHtmlWithWorkaround();
}
void _loadHtmlWithWorkaround() {
// Instead of loading a URL directly, load HTML with proper setup
final html = '''
<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="width=device-width, initial-scale=1.0">
<meta http-equiv="Content-Security-Policy"
content="frame-src https://*.kommunicate.io https://widget.kommunicate.io;">
</head>
<body>
<script type="text/javascript">
// Add a delay to ensure WebView is ready
setTimeout(function() {
(function(d, m){
var kommunicateSettings = {
"appId": "YOUR_APP_ID",
"automaticChatOpenOnNavigation": true,
"popupWidget": true
};
var s = document.createElement("script");
s.type = "text/javascript";
s.async = true;
s.src = "https://widget.kommunicate.io/v2/kommunicate.app";
var h = document.getElementsByTagName("head")[0];
h.appendChild(s);
window.kommunicate = m;
m._globals = kommunicateSettings;
})(document, window.kommunicate || {});
}, 500); // Give WebView time to initialize
</script>
</body>
</html>
''';
controller.loadHtmlString(html);
}
@override
Widget build(BuildContext context) {
return WebViewWidget(controller: controller);
}
}
Solution 2: Use flutter_inappwebview Instead
Sometimes webview_flutter just won't cooperate. flutter_inappwebview often handles these cases better:
dart
import 'package:flutter_inappwebview/flutter_inappwebview.dart';
class ChatWebView extends StatefulWidget {
@override
_ChatWebViewState createState() => _ChatWebViewState();
}
class _ChatWebViewState extends State<ChatWebView> {
late InAppWebViewController webViewController;
@override
Widget build(BuildContext context) {
return InAppWebView(
initialOptions: InAppWebViewGroupOptions(
crossPlatform: InAppWebViewOptions(
javaScriptEnabled: true,
useShouldOverrideUrlLoading: true,
mediaPlaybackRequiresUserGesture: false,
transparentBackground: true,
supportZoom: false,
disableContextMenu: true,
// This is important for iframes
allowFileAccessFromFileURLs: true,
allowUniversalAccessFromFileURLs: true,
),
android: AndroidInAppWebViewOptions(
useHybridComposition: true, // Often helps with complex web content
mixedContentMode: AndroidMixedContentMode.MIXED_CONTENT_ALWAYS_ALLOW,
domStorageEnabled: true,
databaseEnabled: true,
clearSessionCache: true,
thirdPartyCookiesEnabled: true,
allowContentAccess: true,
allowFileAccess: true,
),
),
onWebViewCreated: (controller) {
webViewController = controller;
_loadContent();
},
onConsoleMessage: (controller, consoleMessage) {
print("Console: ${consoleMessage.message}");
},
);
}
void _loadContent() {
// Load your HTML with Kommunicate script
webViewController.loadData(
data: _getHtmlContent(),
mimeType: 'text/html',
encoding: 'utf-8',
);
}
}
Solution 3: The Nuclear Option - Preload Everything
If dynamic creation keeps failing, preload the iframe in your HTML and just show/hide it:
html
<!DOCTYPE html>
<html>
<body>
<!-- Pre-create the iframe structure -->
<div id="kommunicate-widget-container" style="display:none;">
<iframe id="kommunicate-frame"
src="about:blank"
style="width:100%; height:100%; border:none;">
</iframe>
</div>
<script>
// Wait for everything to be ready
window.addEventListener('load', function() {
// Now initialize Kommunicate
// It should use the existing iframe instead of creating a new one
initializeKommunicate();
});
</script>
</body>
</html>
dart
AndroidWebViewController.enableDebugging(true);
Then open chrome://inspect in Chrome to debug the WebView.
xml
<!-- android/app/src/main/AndroidManifest.xml -->
<uses-permission android:name="android.permission.INTERNET"/>
Use Hybrid Composition (for flutter_inappwebview): This renders the WebView using the platform's native view system, which often fixes rendering issues.
Handle SSL Certificate Issues:
dart
onReceivedServerTrustAuthRequest: (controller, challenge) async {
// Only for development! Don't do this in production
return ServerTrustAuthResponse(
action: ServerTrustAuthResponseAction.PROCEED
);
}
Here's the truth: Android WebView is fundamentally more restrictive than iOS's WKWebView. Some third-party web SDKs just aren't designed with Android WebView's limitations in mind. If you've tried everything and it still doesn't work:
Contact the SDK provider (Kommunicate in this case) - they might have Android-specific integration instructions
Consider native integration - Use platform channels to integrate the Android SDK directly
Use a different approach - Maybe host the chat in a separate full-screen WebView instead of embedding it
The most frustrating part? The same code that works perfectly in a regular Chrome browser on Android won't work in Android's WebView. They're different beasts with different security models.
Pro tip: Always test WebView integrations on actual Android devices, not just emulators. Real devices sometimes behave differently, especially older Android versions (looking at you, Android 7-9).