Google Mobile Ads Throwing MissingPluginException - flutter

Question

RewardedAd doesn't work on google_mobile_ads: 2.0.1
I've already searched everywhere and the fixes don't work.
This is the Error on The Logs.
E/DartMessenger( 5002): Uncaught exception in binary message listener
E/DartMessenger( 5002): java.lang.ClassCastException: java.lang.String cannot be cast to java.util.Map
E/DartMessenger( 5002): at io.flutter.plugins.googlemobileads.AdMessageCodec.readValueOfType(AdMessageCodec.java:231)
E/DartMessenger( 5002): at io.flutter.plugin.common.StandardMessageCodec.readValue(StandardMessageCodec.java:340)
E/DartMessenger( 5002): at io.flutter.plugin.common.StandardMessageCodec.readValueOfType(StandardMessageCodec.java:434)
E/DartMessenger( 5002): at io.flutter.plugins.googlemobileads.AdMessageCodec.readValueOfType(AdMessageCodec.java:319)
E/DartMessenger( 5002): at io.flutter.plugin.common.StandardMessageCodec.readValue(StandardMessageCodec.java:340)
E/DartMessenger( 5002): at io.flutter.plugin.common.StandardMethodCodec.decodeMethodCall(StandardMethodCodec.java:51)
E/DartMessenger( 5002): at io.flutter.plugin.common.MethodChannel$IncomingMethodCallHandler.onMessage(MethodChannel.java:260)
E/DartMessenger( 5002): at io.flutter.embedding.engine.dart.DartMessenger.invokeHandler(DartMessenger.java:295)
E/DartMessenger( 5002): at io.flutter.embedding.engine.dart.DartMessenger.lambda$dispatchMessageToQueue$0$DartMessenger(DartMessenger.java:319)
E/DartMessenger( 5002): at io.flutter.embedding.engine.dart.-$$Lambda$DartMessenger$TsixYUB5E6FpKhMtCSQVHKE89gQ.run(Unknown Source:12)
E/DartMessenger( 5002): at android.os.Handler.handleCallback(Handler.java:883)
E/DartMessenger( 5002): at android.os.Handler.dispatchMessage(Handler.java:100)
E/DartMessenger( 5002): at android.os.Looper.loop(Looper.java:237)
E/DartMessenger( 5002): at android.app.ActivityThread.main(ActivityThread.java:7830)
E/DartMessenger( 5002): at java.lang.reflect.Method.invoke(Native Method)
E/DartMessenger( 5002): at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:492)
E/DartMessenger( 5002): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1040)
E/flutter ( 5002): [ERROR:flutter/lib/ui/ui_dart_state.cc(198)] Unhandled Exception: MissingPluginException(No implementation found for method loadRewardedAd on channel plugins.flutter.io/google_mobile_ads)
E/flutter ( 5002): #0 MethodChannel._invokeMethod (package:flutter/src/services/platform_channel.dart:165:7)
E/flutter ( 5002): <asynchronous suspension>
E/flutter ( 5002): #1 RewardedAd.load (package:google_mobile_ads/src/ad_containers.dart:1154:5)
E/flutter ( 5002): <asynchronous suspension>
E/flutter ( 5002):
I already Ad this code on MainActivity
override fun configureFlutterEngine(#NonNull flutterEngine: FlutterEngine) {
GeneratedPluginRegistrant.registerWith(flutterEngine);
}
I made sure also to put this on build.gradle
implementation 'com.google.android.gms:play-services-ads:21.1.0'
I also add this to manifest file
<meta-data
android:name="com.google.android.gms.ads.APPLICATION_ID"
android:value="ca-app-pub-3940256099942544~3347511713" />
This is my implementation
I added this on my main
final initFuture = MobileAds.instance.initialize();
final adState = AdState(initFuture);
And Created another File for AdState
static String get rewardedAdUnitId {
if (Platform.isAndroid) {
return "ca-app-pub-3940256099942544/5224354917";
} else if (Platform.isIOS) {
return "ca-app-pub-3940256099942544/1712485313";
} else {
throw new UnsupportedError("Unsupported platform");
}
}
Future initialization;
AdState(this.initialization);
On my Implementation
void loadRewardedAd(BuildContext context) {
RewardedAd.load(
adUnitId: AdState.rewardedAdUnitId,
request: const AdRequest(),
rewardedAdLoadCallback:
RewardedAdLoadCallback(onAdLoaded: (ad) {
ad.show(
onUserEarnedReward: (ad,rewardPoints){
CommonTools.showMessage(context, 'Energy Received : ');
}
);
ad.fullScreenContentCallback = FullScreenContentCallback(
onAdShowedFullScreenContent: (ad){
},
onAdFailedToShowFullScreenContent: (ad,error){
CommonTools.showMessage(context, 'Ads Not Available For Now');
ad.dispose();
},
onAdDismissedFullScreenContent: (ad){
CommonTools.showMessage(context, 'Ads Not Available For Now');
ad.dispose();
}
);
}, onAdFailedToLoad: (er) {
CommonTools.showMessage(context, 'Ads Not Available For Now');
}));
}

Answer 1

After making this issue traumatize me I managed to make it work. What I did is wrap everything in MaterialApp and put routes on my main Widget.
runApp(
MaterialApp(
routes: <String, WidgetBuilder>{
'/': (BuildContext context) => MyApp()
},
),
);
As for how this works, I don't know how it fix everything but it might help you if you encounter this issue.

Answer 2

The above Main Activity code is for kotlin. Make sure your Main Activity is also in Kotlin.