如何在Firebase消息传递服务和活动之间进行通信?安卓

I know the question about how to communicate between a service and an activity has been answered many times but I also want my own way of doing this to be reviewed and to know if its an acceptable and the right way to do this and what are the drawbacks of how I handled it. First I will state the problem statement with as much detail as I can.I know the question about how to communicate be