实习第三天开发在android圆形菜单
知识参考：http://www.cnblogs.com/zwl12549/archive/2011/04/13/2015366.html和http://www.cnblogs.com/gongcb/p/3642189.html
代码参考：http://www.eoeandroid.com/thread-272601-1-1.html、http://blog.csdn.net/sp6645597/article/details/37928619和http://blog.csdn.net/t12x3456/article/details/7893478还有http://blog.csdn.net/vipzjyno1/article/details/23696537