摘要： 总结Activity的常识之前，先来说说什么是Activity。简单的讲，Activity就是一个屏幕，在屏幕上我们可以放置任何被允许放置的东西，图片，文字，android内置的各类控件等；它的标准定义如下（摘录自android文档）：An activity is a single, focused thing that the user can do. Almost all activities interact with the user, so the Activity class takes care of creating a window for you in which yo.. 阅读全文