Google的Android官方文档：
Actions that can‘t fit in the action bar or aren‘t important enough are hidden in the action overflow. The user can reveal a list of the other actions by pressing the overflow button on the right side (or the deviceMenu button, if available).
关于Android中的ActionBar右边三个点的问题,布布扣,bubuko.com
原文：http://www.cnblogs.com/flyfly121/p/3889599.html