NS_OPTIONS枚举的用法

//NS_OPTIONS，定义选项typedef NS_OPTIONS(NSUInteger, MyOption) {MyOptionNone = 0, //二进制0000,十进制0MyOption1 = 1 << 0,//0001,1MyOption2 = 1 << 1,//0010,2MyOption3 = 1 << 2,//0100,4MyOption4 = 1 << 3,//1000,8};

使用方法：

//声明定义枚举变量MyOption option = MyOption1 | MyOption2;//0001 | 0010 = 0011,3//检查是否包含某选型if ( option & MyOption3 ){ //0011 & 0100 = 0000     //包含MyOption3}else{     //不包含MyOption3}//增加选项:option = option | MyOption4;//0011 | 1000 = 1011, 11//减少选项option = option & (~MyOption4);//1011 & (~1000) = 1011 & 0111 = 0011, 3

转自http://segmentfault.com/a/1190000002949236