Question

我试图播放来自Parse.com的音频文件。运行此代码后，我在获取数据时出现 错误！ 打印出来。我无法理解为什么会发生这种情况。我认为网址是正确的。当我在浏览器中尝试它时，它开始下载我试图播放的音乐。谁能告诉我这段代码有什么问题或者如何解决这个问题？

    let query = PFQuery(className: "AudioFile")
    query.whereKeyExists("audio")
    query.findObjectsInBackgroundWithBlock { (objects:[PFObject]?, error: NSError?) -> Void in
        if error == nil {
            let audio = objects?[0]
            let audioFile = audio?["audio"] as? PFFile
            let filePath = audioFile?.url
            let url = NSURL(fileURLWithPath: filePath!)
            let soundData = NSData(contentsOfURL: url)
            if soundData != nil {
                do {
                    self.audioPlayer = try AVAudioPlayer(data: soundData!) // AVAudioPlayer(contentsOfURL: url)
                    self.audioPlayer.prepareToPlay()
                    self.audioPlayer.volume = 1.0
                    self.audioPlayer.play()
                } catch {
                    print("Error occured while playing music!")
                }
            } else {
                print("Error occured while getting data!")
            }
        } else {
            print("Error occured while downloading file!")
        }
    }

Answer 1

我用这种方式改变了代码。

    query.whereKeyExists("audio")
    query.findObjectsInBackgroundWithBlock { (objects:[PFObject]?, error: NSError?) -> Void in
        if error == nil {
            let audio = objects?[0]
            let audioFile = audio?["audio"] as? PFFile
            audioFile?.getDataInBackgroundWithBlock({ (audio: NSData?, error: NSError?) -> Void in
                if audio != nil {
                    do {
                        self.audioPlayer = try AVAudioPlayer(data: audio!)
                        self.audioPlayer.prepareToPlay()
                        self.audioPlayer.delegate = self
                        self.audioPlayer.volume = 10.0
                        self.audioPlayer.play()
                    } catch {
                        print("Error occured while playing music!")
                    }
                } else {
                    print ("Somehow audio is nil!")
                }
            })
        } else {
            print("Error occured while downloading file!")
        }
    }

值1.0表示音频播放器的全音量，但我无法在模拟器上听到它，所以我使用了10.0。在第一种情况下NSData是零，所以我不得不改变那部分代码并使用getDataInBackgroundWithBlock。此方法是parse方法，它以异步方式查找对象并使用结果调用给定的块。在块中，NSData不再存在，因此AVAudioPlayer正常工作。

快速解析音乐

1 个答案: