MainActivity.java

public class MainActivity extends AppCompatActivity{
  
  protected ServiceMusique service;
  private boolean connected;
  private final ServiceConnection conn = new ServiceConnection() {
      @Override
      public void onServiceConnected(ComponentName componentName, IBinder iBinder) {
          Toast.makeText(getApplicationContext(), "connected To service", Toast.LENGTH_SHORT).show();
          ServiceMusique.MyBinder binder = (ServiceMusique.MyBinder) iBinder;
          service = binder.service;
          connected = true;
      }

      @Override
      public void onServiceDisconnected(ComponentName componentName) {
          connected = false;
      }
  };
  
}

ServiceMusique.java

public class ServiceMusique extends Service {
    public MediaPlayer player = new MediaPlayer();
    private final IBinder binder = new ServiceBinder();


    @Override
    public void onCreate() {
        Toast.makeText(this, "Service ceéé", Toast.LENGTH_SHORT).show();
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        Toast.makeText(this, "Service démarré", Toast.LENGTH_SHORT).show();
        return super.onStartCommand(intent, flags, startId);
    }

    @Override
    public void onDestroy() {
        Toast.makeText(this, "Service détruit", Toast.LENGTH_SHORT).show();
    }

    @Override
    public IBinder onBind(Intent intent) {
        return binder;
    }


    public class MyBinder extends Binder {
        public ServiceMusique getService() {
            return ServiceMusique.this;
        }
    }

}