如何通过服务本身内的通知调用方法？

Question

这是我的代码

FloatingCircle 是由 MainActivity.class

启动的服务

当我单击通知中的关闭按钮时，我想调用方法 Visibility（）

     public class FloatingCircle extends Service {

        public void onCreate () {
                super.onCreate();
                initializeView();
                getScreenSize();
                showFloat();


                NotificationManager notificationManager = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);


                String channelId = "channel-id";
                String channelName = "Channel Name";
                int importance = NotificationManager.IMPORTANCE_HIGH;

                if (android.os.Build.VERSION.SDK_INT >= 26) {
                    NotificationChannel mChannel = new NotificationChannel(
                            channelId, channelName, importance);
                    notificationManager.createNotificationChannel(mChannel);
                }

           Intent intent = new Intent(getApplicationContext(), FloatingCircle.class **// What should be here could you suggest me**);
                intent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK | Intent.FLAG_ACTIVITY_CLEAR_TASK);
                PendingIntent pIntent = PendingIntent.getService(this, 0, intent, 0);


                NotificationCompat.Builder mBuilder = new NotificationCompat.Builder(context, channelId)
                        .setSmallIcon(R.mipmap.ic_launcher)//R.mipmap.ic_launcher
                        .setContentTitle("Bubble Life")
                        .setContentText("Touch to On/Off")
                        .addAction(R.drawable.ic_action_name,
                                "Dismiss", pIntent)// Here Dismiss is Button shown in notification
                        .setDefaults(NotificationCompat.DEFAULT_ALL);

                notificationManager.notify(0, mBuilder.build());
        }
        }

This method must be invoked when Dismiss Button is clicked

            public void Visibility(()
            {
                //some code here
                windowManager.removeViewImmediate(smallCircle);
                Log.d("lol","Done Killing");
            }

 public void killbubble()
    {

        Visibility();
        selfstop();

    }

我尝试了创建另一项服务并调用Floatingclass方法的一件事。...

public class MethodCaller extends Service {

    FloatingCircle floatingCircle=new FloatingCircle();

    @Override
    public void onCreate() {
        super.onCreate();
        Log.d("lol","yeah");

        //Toast.makeText(getApplicationContext(),"lol",Toast.LENGTH_LONG).show();
    }

    @Nullable
    @Override
    public IBinder onBind(Intent intent) {

        return null;
    }


    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {


        floatingCircle.killbubble();
        stopSelf();
        return flags;
    }

}

我已经成功了，但这给了我一个错误...

Caused by: java.lang.NullPointerException: Attempt to invoke interface method 'void android.view.WindowManager.removeViewImmediate(android.view.View)' on a null object reference
        at com.anam.floatimage.model.FloatingCircle.Visibility(FloatingCircle.java:547)
        at com.anam.floatimage.model.FloatingCircle.killbubble(FloatingCircle.java:777)
        at com.anam.floatimage.MethodCaller.onStartCommand(MethodCaller.java:36)