android原生观察者和被观察者模式java.util.Observable

项目中用到这个，所以记录一下

https://blog.csdn.net/iteye_5649/article/details/82636534?utm_medium=distribute.pc_relevant.none-task-blog-2~default~baidujs_baidulandingword~default-1-82636534-blog-115570733.pc_relevant_vip_default&spm=1001.2101.3001.4242.1&utm_relevant_index=4

 

https://blog.csdn.net/qq_39464369/article/details/88425255