Android源码学习之观察者模式应用及优点介绍
观察者模式定义: Define a one-to-many dependency between objects so that when one object changes state, all its dependents aer notified and updated automatica
观察者模式定义: Define a one-to-many dependency between objects so that when one object changes state, all its dependents aer notified and updated automatica
Detecting When The User Has Clicked Cancel One of the things you may want to do is to be notified when the user clicks cancel, aborting a page unload.