ios - 如何在 Swift 中使用常量 : AVAudioSessionInterruptionNotification

Question

这是我在 Swift 中的工作代码。问题是我使用 UInt 作为中间类型。

func handleInterruption(notification: NSNotification) {
    let interruptionType  = notification.userInfo?[AVAudioSessionInterruptionTypeKey] as! UInt
    if (interruptionType == AVAudioSessionInterruptionType.Began.rawValue) {
        // started
    } else if (interruptionType == AVAudioSessionInterruptionType.Ended.rawValue) {
        // ended
        let interruptionOption  = notification.userInfo?[AVAudioSessionInterruptionOptionKey] as! UInt
        if interruptionOption == AVAudioSessionInterruptionOptions.OptionShouldResume.rawValue {
             // resume!                
        }
    }
}

有没有更好的办法？

Answer 1

这种方法类似于 Matt 的方法，但由于 Swift 3 的变化(主要是 userInfo 为 [AnyHashable : Any])，我们可以使我们的代码多一点“Swifty”(不打开 rawValue 或转换为 AnyObject 等):

func handleInterruption(notification: Notification) {

    guard let userInfo = notification.userInfo,
        let interruptionTypeRawValue = userInfo[AVAudioSessionInterruptionTypeKey] as? UInt,
        let interruptionType = AVAudioSessionInterruptionType(rawValue: interruptionTypeRawValue) else {
        return
    }    

    switch interruptionType {
    case .began:
        print("interruption began")
    case .ended:
        print("interruption ended")
    }

}