NoSuchMethodError: Class 'bool' has no instance method 'then' in MethodChannel handlers (Dart 3 compatibility)

[aligh98]

Hello,

When using the latest version of the Adivery Flutter plugin (4.8.8) on Dart 3, an unhandled exception is thrown in the Flutter framework whenever a MethodChannel event (like onAdLoaded, onAdLoadFailed, etc.) is received from the native side.

This happens because the handle(MethodCall call) methods in both BannerAdEventHandler and NativeAdEventHandler return a boolean true while their return type is declared as Future<dynamic>, but the method itself is not marked as async.

Stacktrace

NoSuchMethodError: Class 'bool' has no instance method 'then'.
Receiver: true
Tried calling: then<dynamic>(Closure: (dynamic) => dynamic)
    at BannerAdEventHandler.handle (package:adivery/adivery_ads.dart:159)
    at MethodChannel._handleAsMethodCall (package:flutter/src/services/platform_channel.dart:608)

Root Cause

In lib/adivery_ads.dart:

  // Missing 'async' keyword here
  Future<dynamic> handle(MethodCall call) { 
    switch (call.method) {
      // ...
    }
    return true as dynamic; // Returns a boolean, but MethodChannel expects a Future
  }

Flutter's MethodChannel._handleAsMethodCall tries to call .then() on the returned result. Since true is a bool and not a Future, it throws a NoSuchMethodError which breaks the error handling and app state.

Solution

Add the async keyword to the handle methods in both BannerAdEventHandler and NativeAdEventHandler, or return Future.value(true).

Example Fix:

  Future<dynamic> handle(MethodCall call) async {
    switch (call.method) {
        // ...
    }
    return true;
  }

Please fix this in the next release, as it currently causes apps to crash or silently fail when an ad fails to load. Thank you!