swift-静音模式下播放声音处理

///写在Appdelegate didFinishLaunchingWithOptions下
       do {
            try AVAudioSession.sharedInstance().setCategory(AVAudioSession.Category.playback)
            try AVAudioSession.sharedInstance().setActive(true)
            
        } catch let error as NSError {
            print("error: \(error.localizedDescription)")
        }