Remove variables from an android service

Hello stackoverflow community I'm doing an app that plays streaming audio as a service in the background, what I want to do is remove variables from the service from the Activity as well to update the play / pause buttons This is my service code

import android.annotation.SuppressLint;
import android.app.Service;
import android.content.Intent;
import android.media.AudioManager;
import android.media.MediaPlayer;
import android.net.Uri;
import android.os.IBinder;
import android.util.Log;

import java.io.IOException;

public class PlayRadio extends Service{
    private static final String LOGCAT = null;
    public MediaPlayer mediaPlayer;


    public void onCreate(){
        super.onCreate();
        Log.d(LOGCAT, "Service Started!");
        mediaPlayer = new MediaPlayer();

    }

    @SuppressLint("WrongConstant")
    public int onStartCommand(Intent intent, int flags, int startId){
        try {
            mediaPlayer.setDataSource(getApplicationContext(), Uri.parse("http://localhost:8080/hls/radio.m3u8"));
            mediaPlayer.setAudioStreamType(AudioManager.STREAM_MUSIC);
            mediaPlayer.prepare();
            mediaPlayer.start();

        } catch (IOException e) {
            e.printStackTrace();
        }

        Log.d(LOGCAT, "Media Player started!");
        if(!mediaPlayer.isLooping()){
            Log.d(LOGCAT, "Problem in Playing Audio");
        }
        return 1;
    }

    public void onStop(){
        mediaPlayer.stop();
        mediaPlayer.release();
    }

    public boolean isPlaying(){

        if(mediaPlayer.isLooping()){
            return true;
        } else {
            return false;
        }


    }

    public void onPause(){
        mediaPlayer.stop();
        mediaPlayer.release();
    }

    public void onDestroy(){
        mediaPlayer.stop();
        mediaPlayer.release();
    }

    @Override
    public IBinder onBind(Intent objIndent) {
        return null;
    }

What I want is from the activity call isPlaying () so to know if the audio is playing or not and update the buttons

EDITO

This is how I call from the Activity (within the event of the button)

if (!isPLAYING) {

                    isPLAYING = true;
                    Intent objIntent = new Intent(getApplicationContext(), PlayRadio.class);
                    startService(objIntent); 
               fab.setImageResource(android.R.drawable.ic_media_pause); //Cambia el icono
                } else {
                    isPLAYING = false;
                    Intent objIntent = new Intent(getApplicationContext(), PlayRadio.class);
                    stopService(objIntent); 
               fab.setImageResource(android.R.drawable.ic_media_play); //Cambia el icono
                }

The button changes icon from play to play and the music plays quietly When leaving the app it continues playing as a service in the background, the problem is that when you re-enter the app the button is in "Play" and when you click it launches the service that was already running, being that should close it