在Android中，如果实现了ActivityAware接口的组件的onAttachedToActivity方法未被触发，可能是因为忘记在AndroidManifest.xml文件中注册该组件。

下面是一个示例代码，演示了如何正确注册ActivityAware组件：

首先，创建一个实现了ActivityAware接口的类，例如MyActivityAware：

import android.app.Activity;
import android.content.Context;
import android.util.Log;

import androidx.annotation.NonNull;
import androidx.lifecycle.Lifecycle;
import androidx.lifecycle.LifecycleObserver;
import androidx.lifecycle.OnLifecycleEvent;

import io.flutter.embedding.android.FlutterActivity;
import io.flutter.embedding.android.FlutterActivityAndFragmentDelegate;
import io.flutter.embedding.engine.FlutterEngine;
import io.flutter.embedding.engine.FlutterEngineGroup;
import io.flutter.embedding.engine.FlutterJNI;
import io.flutter.embedding.engine.dart.DartExecutor;
import io.flutter.embedding.engine.loader.FlutterLoader;
import io.flutter.embedding.engine.plugins.activity.ActivityPluginBinding;
import io.flutter.embedding.engine.plugins.activity.ActivityPluginRegistry;
import io.flutter.embedding.engine.plugins.activity.ActivityPluginRegistry.ActivityLifecycleListener;
import io.flutter.embedding.engine.plugins.activity.ActivityPluginRegistry.NewIntentListener;
import io.flutter.embedding.engine.plugins.lifecycle.FlutterLifecycleAdapter;
import io.flutter.embedding.engine.renderer.FlutterRenderer;
import io.flutter.embedding.engine.systemchannels.FlutterSystemChannels;
import io.flutter.embedding.plugins.FlutterPlugin;
import io.flutter.embedding.plugins.GeneratedPluginRegistrant;
import io.flutter.plugin.common.BinaryMessenger;
import io.flutter.plugin.common.MethodCall;
import io.flutter.plugin.common.MethodChannel;
import io.flutter.plugin.common.PluginRegistry;
import io.flutter.plugin.platform.PlatformViewRegistry;

public class MyActivityAware implements FlutterPlugin, ActivityAware {
    private Activity activity;

    @Override
    public void onAttachedToEngine(@NonNull FlutterPluginBinding binding) {
        // 初始化插件
    }

    @Override
    public void onDetachedFromEngine(@NonNull FlutterPluginBinding binding) {
        // 清理插件
    }

    @Override
    public void onAttachedToActivity(@NonNull ActivityPluginBinding binding) {
        activity = binding.getActivity();
        // 在这里可以对Activity进行操作
        Log.d("MyActivityAware", "onAttachedToActivity triggered");
    }

    @Override
    public void onDetachedFromActivityForConfigChanges() {
        // Activity发生配置变化时的回调
    }

    @Override
    public void onReattachedToActivityForConfigChanges(@NonNull ActivityPluginBinding binding) {
        // Activity重新关联时的回调
    }

    @Override
    public void onDetachedFromActivity() {
        // Activity解除关联时的回调
    }
}

然后，在AndroidManifest.xml文件中注册这个组件：

请注意，在activity标签中，我们添加了一个meta-data标签，将MyActivityAware注册到Activity中。

这样，当应用程序启动时，MyActivityAware的onAttachedToActivity方法将被触发，并且您可以在该方法中对Activity进行操作。