Question

我有一个不断从蓝牙传感器接收整数数据的应用程序，我这样做，如果整数小于50，那么它应该播放MP3。

问题在于传感器非常快速地检查并发送整数，导致音频实例太多，基本上mp3文件同时播放的次数太多。我怎样才能让它在重新开始之前完成音频？

这是主要代码：

var player: AVAudioPlayer?




if let unwrappedString = Reading {
            let optionalInt = Int(unwrappedString)
            if let upwrappedInt = optionalInt {
                if(upwrappedInt < 50){
                    DispatchQueue.global(qos: .background).async {
                        self.playSound()

                    }
                }
            }
            }

声音功能：

 func playSound() {
        guard let url = Bundle.main.url(forResource: "beep1", withExtension: "mp3") else {
            print("url not found")
            return
        }

        do {
            /// this codes for making this app ready to takeover the device audio
            try AVAudioSession.sharedInstance().setCategory(AVAudioSessionCategoryPlayback)
            try AVAudioSession.sharedInstance().setActive(true)

            /// change fileTypeHint according to the type of your audio file (you can omit this)
            player = try AVAudioPlayer(contentsOf: url, fileTypeHint: AVFileTypeMPEGLayer3)

            // no need for prepareToPlay because prepareToPlay is happen automatically when calling play()
            player!.play()
        } catch let error as NSError {
            print("error: \(error.localizedDescription)")
        }
    }

Answer 1

如果音频播放器已播放（isPlaying），请勿开始播放！

https://developer.apple.com/reference/avfoundation/avaudioplayer/1390139-isplaying

Answer 2

我相信AVAudioPlayer有一个委托方法来检查音频是否已经播放完毕：

-(void)audioPlayerDidFinishPlaying:(AVAudioPlayer *)player successfully:(BOOL)flag
{
    // ----------------------------------------------
    // set your custom boolean flag 'isPlayingAudio' 
    // to false so you can play another audio again
    // ----------------------------------------------
}

...

-(void)monitorBluetoothNumber 
{
    if(bluetoothNumber < 50 && !self.isPlayingAudio) 
    {
        [self playMusic];
        self.isPlayingAudio = YES;
    }
}

您需要设置音频播放器并明确设置其代理。

代码是Objective C，但您可以轻松适应Swift。

一次播放一个声音实例

2 个答案: