ios - 在静音模式下播放声音，应用已终止状态

Question

我需要在ios应用中收到推送通知时播放自定义声音。

我知道，苹果不支持静音模式下的声音提示。我尝试发送带有自定义声音的推送通知。当设备处于非静音状态时播放，并以静音模式振动。

但是，最近我发现了一个应用程序-Chipolo，即使该应用程序处于终止状态，该应用程序也可以以静音模式显示自定义声音。

播放声音警报时使用了什么技术？

任何帮助都非常感谢!

Answer 1

收到推送通知时，我们无法更改系统声音，但可以使用MediaPlayer和AVFoundation播放音频。我们需要使用Notification Service扩展来处理前台和后台通知

在NotificationService扩展中

import UserNotifications
import AVFoundation
import MediaPlayer

class NotificationService: UNNotificationServiceExtension {


    var contentHandler: ((UNNotificationContent) -> Void)?
    var bestAttemptContent: UNMutableNotificationContent?

    override func didReceive(_ request: UNNotificationRequest, withContentHandler contentHandler: @escaping (UNNotificationContent) -> Void) {
        self.contentHandler = contentHandler
        bestAttemptContent = (request.content.mutableCopy() as? UNMutableNotificationContent)

        // Properties
        var error:NSError?
        var audioPlayer = AVAudioPlayer()

        let tempInfo = request.content.userInfo as! [String:NSObject]
        var songName = ""
        if tempInfo.index(forKey: "SoundFileName") != nil {
            songName = (tempInfo["SoundFileName"] as! String)
        }

        var opecode = ""
        if tempInfo.index(forKey: "Opcode") != nil {
            opecode = (tempInfo["Opcode"] as! String)
        }

        if opecode == "RingDevice" {
            var songTitle = ""
            var songExtension = ""
            if songName == "" {
                songTitle = "Input"
                songExtension = "caf"
            } else  {
                let testStr = songName.components(separatedBy: ".")
                songTitle = "\(testStr[0])"
                songExtension = "\(testStr[1])"
            }

                if let url = Bundle.main.url(forResource: "\(songTitle)", withExtension: "\(songExtension)")  {

                    let volumeView = MPVolumeView()
                    if let view = volumeView.subviews.first as? UISlider{
                        view.value = 1.0 //---0 t0 1.0---

                    }

                    do {
                        try AVAudioSession.sharedInstance().setCategory(AVAudioSessionCategoryPlayback)

                        try AVAudioSession.sharedInstance().setActive(true)

                        audioPlayer = try AVAudioPlayer(contentsOf: url,  fileTypeHint: AVFileType.caf.rawValue)
                        audioPlayer.volume = 1.0
                        DispatchQueue.main.asyncAfter(deadline: .now() + 5) { // Give 5 sec delay to play audio or else audio will not hearable
                             audioPlayer.play()
                        }
                    } catch _ as NSError {
                        print("[SoundPlayer] There was an error: \(String(describing: error))")
                    }

                    if (audioPlayer.isPlaying) {
                        audioPlayer.stop()
                    }
                    audioPlayer.play()
                }
        }


        if let bestAttemptContent = bestAttemptContent {
            // Modify the notification content here...            
            bestAttemptContent.title = "\(bestAttemptContent.title)"

            contentHandler(bestAttemptContent)
        }
    }

    override func serviceExtensionTimeWillExpire() {
        // Called just before the extension will be terminated by the system.
        // Use this as an opportunity to deliver your "best attempt" at modified content, otherwise the original push payload will be used.
        if let contentHandler = contentHandler, let bestAttemptContent =  bestAttemptContent {
            contentHandler(bestAttemptContent)
        }
    }

}

就我而言，我需要检查pushnotification SoundFileName和 Opcode中的两个参数。如果 Opcode是 RingDevice表示我正在播放PushNotification中提到的声音

不要忘记启用后台模式



希望这能够帮到你 :)