Not able to show the dynamic layout created using java code when running a background service(FirebaseMessagingService)

Not able to show the dynamic layout created using java code when running a background service(FirebaseMessagingService) I want my app to show a Layout created dynamically using java code whenever it received a notification. Here is the code I implemented for that. You can find the code inside the onMessageReceived()

Now I am stuck don't know what to do?

package com.fitness.client.services;

import android.annotation.SuppressLint;
import android.app.Notification;
import android.app.NotificationChannel;
import android.app.NotificationManager;
import android.app.PendingIntent;
import android.content.Context;
import android.content.Intent;
import android.graphics.Color;
import android.media.RingtoneManager;
import android.net.Uri;
import android.os.Build;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.LinearLayout;
import android.widget.RelativeLayout;
import android.widget.RemoteViews;
import android.widget.TextView;
import android.widget.Toast;

import androidx.annotation.NonNull;
import androidx.core.app.NotificationCompat;
import androidx.core.app.NotificationManagerCompat;
import androidx.work.OneTimeWorkRequest;
import androidx.work.WorkManager;

import com.fitness.client.App;
import com.fitness.client.R;
import com.fitness.client.api.RetroFitFactory;
import com.fitness.client.api.order.OrderDetails;
import com.fitness.client.api.order.OrderService;
import com.fitness.client.objects.Order;
import com.fitness.client.ui.UiActivity;
import com.fitness.client.ui.main.MainActivity;
import com.google.firebase.messaging.FirebaseMessagingService;
import com.google.firebase.messaging.RemoteMessage;

import java.util.Objects;

import retrofit2.Call;
import retrofit2.Callback;
import retrofit2.Response;
import retrofit2.Retrofit;

public class NotificationReceiver extends FirebaseMessagingService {

    private static final String TAG = "MyFirebaseMsgService";
    TextView userName, extraPeople, slots, date, area;
    Button accept, reject;
    RelativeLayout mainUi;

    public static Boolean notifyService = false;

    @Override
    public void onCreate() {
        super.onCreate();

        Toast.makeText(this, "Service Created", Toast.LENGTH_SHORT).show();


    }

    @Override
    public void onMessageReceived(@NonNull RemoteMessage remoteMessage) {
        super.onMessageReceived(remoteMessage);
        //Start UiActivity
        notifyService = true;
        long objectId = Long.parseLong(Objects.requireNonNull(Objects.requireNonNull(remoteMessage.getNotification()).getBody()));
        Log.e("Check","order id"+ Objects.requireNonNull(remoteMessage.getNotification()).getBody());
        Log.e(TAG, "onMessageReceived: orderId: " + objectId);
        // TODO: 08-04-2020 Call a get request for order api end-point using id
        RetroFitFactory.getRetrofitCallFor(OrderService.class)
                .getOrderDetails(objectId)
                .enqueue(new Callback<OrderDetails>() {
                    @Override
                    public void onResponse(@NonNull Call<OrderDetails> call, @NonNull Response<OrderDetails> response) {

                        Order object = null;
                        if (response.body() != null) {
                            object = response.body().getData();
                        }
                        Context context = NotificationReceiver.this;

                        assert object != null;
                        String username = object.getUser().getName();
                        Log.e(TAG, "onResponse: Username" + username );
                        String extrapeople ="1";
                        String userslots = object.getSlots().getFrom() + object.getSlots().getTo();
                        Log.e(TAG, "onResponse: slots" + userslots );
                        String userdate = object.getBooking_date();
                        String userarea = "Navi Mumbai";

                        LinearLayout mainlayot = new LinearLayout(context);

                        mainlayot.setLayoutParams(new LinearLayout.LayoutParams(
                                LinearLayout.LayoutParams.MATCH_PARENT,
                                LinearLayout.LayoutParams.MATCH_PARENT
                        ));

                        mainlayot.setBackgroundColor(Color.parseColor("#8F75D8"));

                        TextView user_name = new TextView(context);
                        user_name.setLayoutParams(new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT));

                        user_name.setTextAlignment(View.TEXT_ALIGNMENT_CENTER);
                        user_name.setText(username);
                        mainlayot.addView(user_name);


                        TextView extra_people = new TextView(context);
                        extra_people.setLayoutParams(new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT));

                        extra_people.setTextAlignment(View.TEXT_ALIGNMENT_CENTER);
                        extra_people.setText("1");
                        mainlayot.addView(extra_people);

                        TextView date_booking = new TextView(context);
                        date_booking.setLayoutParams(new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT));

                        date_booking.setTextAlignment(View.TEXT_ALIGNMENT_CENTER);
                        date_booking.setText(userdate);
                        mainlayot.addView(date_booking);


                        TextView user_slot = new TextView(context);
                        user_slot.setLayoutParams(new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT));

                        user_slot.setTextAlignment(View.TEXT_ALIGNMENT_CENTER);
                        user_slot.setText(userslots);
                        mainlayot.addView(user_slot);


                        TextView user_area = new TextView(context);
                        user_area.setLayoutParams(new LinearLayout.LayoutParams(LinearLayout.LayoutParams.WRAP_CONTENT, LinearLayout.LayoutParams.WRAP_CONTENT));

                        user_area.setTextAlignment(View.TEXT_ALIGNMENT_CENTER);
                        user_area.setText("Navi Mumbai");
                        mainlayot.addView(user_area);

                        mainlayot.setVisibility(View.VISIBLE);




                    }

                    @Override
                    public void onFailure(@NonNull Call<OrderDetails> call, @NonNull Throwable t) {
                        Toast.makeText(NotificationReceiver.this, t.getMessage(), Toast.LENGTH_SHORT).show();
                    }
                });
    }
}