一、普通枚举
1、写法
typedef NS_ENUM (NSInteger, ColorType) {
RedColor,
BlackColor,
WhiteColor
};
NS_ENUM 标示；NSInteger 固定类型，不能为NSString其他类型;ColorType枚举的类型；ColorType 声明的变量只能为单个值
二、位移枚举
1、写法
typedef NS_OPTIONS (NSUInteger, NetWorkType) {
Unknown = 0, // 0
NotReachable = 1 << 1, // 10 2^1
WiFi = 1 << 2, // 100 2^2
WWAN = 1 << 3 // 1000 2^3
};
NS_OPTIONS 标示；NSUInteger 固定类型；NetWorkType 枚举的类型；NetWorkType 声明的变量只能可以为多个值
2、例
NetWorkType netWorkType=WiFi|WWAN;
[self checkUserNetWorkState:netWorkType];
-(void)checkUserNetWorkState:(NetWorkType )stateType{
//进行&运算
if (stateType&NotReachable) {
NSLog(@"NotReachable");
}
if(stateType&WiFi){
NSLog(@"WiFi");
}
if(stateType&WWAN){
NSLog(@"WWAN");
}
}
输出：
2017-06-15 20:50:23.754 BitOperation[1450:34567] WiFi
2017-06-15 20:50:23.755 BitOperation[1450:34567] WWAN
3、iOS系统API例
typedef NS_OPTIONS(NSUInteger, UIViewAutoresizing) {
UIViewAutoresizingNone = 0,
UIViewAutoresizingFlexibleLeftMargin = 1 << 0,
UIViewAutoresizingFlexibleWidth = 1 << 1,
UIViewAutoresizingFlexibleRightMargin = 1 << 2,
UIViewAutoresizingFlexibleTopMargin = 1 << 3,
UIViewAutoresizingFlexibleHeight = 1 << 4,
UIViewAutoresizingFlexibleBottomMargin = 1 << 5
};
UIView*view = [[UIView alloc]init];
//view自动调整自己的宽度，保证与superView左边和右边的距离不变。自动调整自己的高度，保证与superView顶部和底部的距离不变
view.autoresizingMask=UIViewAutoresizingFlexibleWidth|UIViewAutoresizingFlexibleHeight;
[self.view addSubview:view];
