1、Android:state_focused 官方解释为当前view获得焦点的时候
2、android:state_window_focused 当前view所在的窗体获得焦点的时候
3、android:state_enabled 当前view可以被点击或者触发触摸事件的时候
4、android:state_checkable 当前view是否可以被check，比如checkBox，RadioButton是可以check的
5、android:state_checked 当前view是否被check 比如checkBox被check的
6、android:state_selected 当前view是否被选中
7、android:state_pressed 当前view是否被按下
8、android:state_activated 这个比较难解释，官方解释是set when a view or its parent has been "activated" meaning the user has currently marked it as being of interest.
