android下，java的观察者模式学习-android, java observer mode learning

对安卓观察者模式的实现，在java的环境先实现其功能，对于想了解使用安卓的观察者模式是一个很好的鉴定。-Andrews observer mode to achieve, the environment in the first java achieve its function, for those who want to understand the use of Android is a good observer pattern identification.