NS_ENUM

通用枚举值

typedef NS_ENUM(NSInteger, UIControlContentHorizontalAlignment) {
    UIControlContentHorizontalAlignmentCenter = 0,
    UIControlContentHorizontalAlignmentLeft   = 1,
    UIControlContentHorizontalAlignmentRight  = 2,
    UIControlContentHorizontalAlignmentFill   = 3,
};

NS_OPTIONS

位移相关操作的枚举值

typedef NS_OPTIONS(NSUInteger, UIControlState) {
    UIControlStateNormal       = 0,
    UIControlStateHighlighted  = 1 << 0,
    UIControlStateDisabled     = 1 << 1,
    UIControlStateSelected     = 1 << 2,
    UIControlStateApplication  = 0x00FF0000,
    UIControlStateReserved     = 0xFF000000
};

• 通常情况下我们用的枚举是NS_ENUM
• 当一个枚举变量可能要代表多个属性的时候，就要用到NS_OPTIONS（NS_OPTIONS代表的也是一个值，只不过是两个或多个值按位移后的值）

self.tableView.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;

共

同

进

步

给个喜欢喔O(∩_∩)O