android添加自定义的系统服务供上层调用

https://blog.youkuaiyun.com/qq_28827333/article/details/89455820
https://www.cnblogs.com/xerrard/p/5206192.html
https://www.cnblogs.com/liam999/p/5933827.html

https://blog.youkuaiyun.com/liujunpen/article/details/107655233

https://blog.youkuaiyun.com/tkwxty/article/details/104000821

在网上看到这五篇文章写的不错，可以教会你如何定义一个系统服务