I found Error in compiling extension in Niotron IDE

when compiling the extension in Niotron IDE, I encountered errors. I didn’t understand why the errors appeared

javac] Note: Wrote file file:/compiler/androidX/build/hKDyb/classes/simple_components.json
[javac] Note: Wrote file file:/compiler/androidX/build/hKDyb/classes/simple_components.txt
[javac] Note: Wrote file file:/compiler/androidX/build/hKDyb/classes/simple_components_build_info.json
[javac] Note: Wrote file file:/compiler/androidX/build/hKDyb/classes/AutogeneratedOdeMessages.java
[javac] Note: Wrote file file:/compiler/androidX/build/hKDyb/classes/ComponentsTranslation.java
[javac] /compiler/androidX/src/hKDyb/Dev/amarjeet/sir/OneSignal.java:17: error: package com.onesignal does not existjavac] import com.onesignal.NotificationReceivedHandler;
[javac] ^
[javac] /compiler/androidX/src/hKDyb/Dev/amarjeet/sir/OneSignal.java:18: error: package com.onesignal does not exist
[javac] import com.onesignal.OSNotification;
[javac] ^
[javac] /compiler/androidX/src/hKDyb/Dev/amarjeet/sir/OneSignal.java:19: error: package com.onesignal does not exist
[javac] import com.onesignal.PostNotificationResponseHandler;
[javac] ^
[javac] /compiler/androidX/src/hKDyb/Dev/amarjeet/sir/OneSignal.java:67: error: cannot find symbol
[javac] private class OneSignalNotificationHandler implementsNotificationReceivedHandler {
[javac] ^
[javac] symbol: class NotificationReceivedHandler
[javac] location: class OneSignal
[javac] /compiler/androidX/src/hKDyb/Dev/amarjeet/sir/OneSignal.java:69: error: cannot find symbol
[javac] public void notificationReceived(OSNotification notification) {
[javac] ^
[javac] symbol: class OSNotification
[javac] location: class OneSignal.OneSignalNotificationHandler
[javac] /compiler/androidX/src/hKDyb/Dev/amarjeet/sir/OneSignal.java:74: error: cannot find symbol
[javac] private class OneSignalPostNotificationHandler implements PostNotificationResponseHandler {
[javac] ^javac] ^
[javac] symbol: class PostNotificationResponseHandler
[javac] location: class OneSignal
[javac] 6 errors

package Dev.amarjeet.sir;

import android.app.Activity;
import android.content.Context;
import com.google.appinventor.components.annotations.*;
import com.google.appinventor.components.common.ComponentCategory;
import com.google.appinventor.components.runtime.AndroidNonvisibleComponent;
import com.google.appinventor.components.runtime.ComponentContainer;
import com.google.appinventor.components.runtime.EventDispatcher;

import android.app.Activity;
import android.content.Context;
import android.util.Log;
import com.google.appinventor.components.annotations.*;
import com.google.appinventor.components.common.ComponentCategory;
import com.google.appinventor.components.runtime.*;
import com.onesignal.NotificationReceivedHandler;
import com.onesignal.OSNotification;
import com.onesignal.PostNotificationResponseHandler;
import org.json.JSONException;
import org.json.JSONObject;

@DesignerComponent(
        version = 1,
        description = "OneSignal Push Notification Extension",
        category = ComponentCategory.EXTENSION,
        nonVisible = true,
        iconName = "https://example.com/icon.png")

@SimpleObject(external = true)

public class OneSignal extends AndroidNonvisibleComponent implements Component {

    private static final String LOG_TAG = "OneSignalExtension";

    private Context context;
    private String appId;

    public OneSignal(ComponentContainer container) {
        super(container.$form());
        this.context = container.$context();
        this.appId = "";
    }

    @SimpleProperty(description = "The OneSignal app ID.")
    public void AppId(String appId) {
        this.appId = appId;
    }

    @SimpleFunction(description = "Initializes OneSignal with the specified app ID.")
    public void Initialize() {
        OneSignal.init(context, appId, new OneSignalNotificationHandler());
    }

    @SimpleFunction(description = "Sends a push notification to the specified user.")
    public void SendNotification(String message, String userId) {
        JSONObject data = new JSONObject();
        try {
            data.put("message", message);
            data.put("userId", userId);
            OneSignal.postNotification(data, new OneSignalPostNotificationHandler());
        } catch (JSONException e) {
            Log.e(LOG_TAG, "Error creating JSON object for push notification", e);
        }
    }

    private class OneSignalNotificationHandler implements NotificationReceivedHandler {
        @Override
        public void notificationReceived(OSNotification notification) {
            Log.i(LOG_TAG, "Received OneSignal notification: " + notification.payload.body);
        }
    }

    private class OneSignalPostNotificationHandler implements PostNotificationResponseHandler {
        @Override
        public void onSuccess(JSONObject response) {
            Log.i(LOG_TAG, "OneSignal push notification sent successfully.");
        }

        @Override
        public void onFailure(JSONObject response) {
            Log.e(LOG_TAG, "Error sending OneSignal push notification: " + response.toString());
        }
    }
}

Hello @Amarjeet_kumar ,
Welcome to Niotron

First i have made some changes to your topic.

And most probably the reason for your error is that you haven’t uploaded library in the IDE, as it is not able to get those classes which you are importing
First check the libraries that you have added and confirm that are they right and available for the code