如何在Swift 2.0中处理掩码(枚举)？

例如,在EventKit中,EKCalendar上有一个名为supportedEventAvailabilities的属性,它的类型为EKCalendarEventAvailabilityMask.它是所有支持的事件可用性的掩码.我知道你理论上可以像这样设置它们(如果这个属性是可写的)：

calendar.supportedEventAvailabilities = [.Busy, .Free]

但是你怎么再读这些价值呢？我最终得到了这样的代码：

let availabilities = calendar.supportedEventAvailabilities
if (availabilities.rawValue & EKCalendarEventAvailabilityMask.Busy.rawValue) == EKCalendarEventAvailabilityMask.Busy.rawValue {
    // 'Busy' is in there!
}
if (availabilities.rawValue & EKCalendarEventAvailabilityMask.Free.rawValue) == EKCalendarEventAvailabilityMask.Free.rawValue {
    // 'Free' is in there!
}

但这感觉不对.有谁知道如何正确地做到这一点？

EKCalendarEventAvailabilityMask符合新的OptionSetType
从SetAlgebraType继承并提供类似集合的接口的协议.您可以查看会员资格

let availabilities = calendar.supportedEventAvailabilities
if availabilities.contains(.Busy) {
    // 'Busy' is in there!
}

要么

if availabilities.isSupersetOf([.Busy, .Free]) {
    // Both .Busy and .Free are available ...
}

要么

if availabilities.intersect([.Busy, .Free]) != [] {
    // At least one of .Busy and .Free is available ...
}

有关更多信息,请参阅protocol SetAlgebraType在“Swift标准库参考”中.