Swift ERROR : : Call can throw, but it is not marked with 'try' and the error is not handled

Question

我刚开始学习 Swift 并且，我正在尝试将一首歌曲添加到我的代码中以在我按下按钮时播放它，但出现该错误。如何解决这个错误？

var buttonAudioPlayer = AVAudioPlayer()

@IBAction func btnWarning(sender: UIButton) {
    play()
}

override func viewDidLoad() {
    super.viewDidLoad()
}

func play() {
    let buttonAudioURL = NSURL(fileURLWithPath: NSBundle.mainBundle().pathForResource("warning", ofType: "mp3")!)
    let one = 1

    if one == 1 {
        buttonAudioPlayer = AVAudioPlayer(contentsOfURL: buttonAudioURL) //getting the error in this line
        buttonAudioPlayer.prepareToPlay()
        buttonAudioPlayer.play()
    }
}

Answer 1

编译器正确地告诉您初始化程序可以抛出错误，因为 method declaration 正确指出（例如，当 NSURL 不存在时）：

init(contentsOfURL url: NSURL) throws

因此，您作为开发人员必须处理最终发生的错误：

do {
    let buttonAudioPlayer = try AVAudioPlayer(contentsOfURL: buttonAudioURL)
} catch let error {
    print("error occured \(error)")
}

或者您可以通过

告诉编译器调用实际上总是会成功

let buttonAudioPlayer = try! AVAudioPlayer(contentsOfURL: buttonAudioURL)

但这会导致您的应用程序崩溃如果创建实际上没有成功 - 请小心。如果您尝试加载有的应用程序资源，您应该只使用第二种方法。

Answer 2

有可能AVAudioPlayer(contentsOfURL: buttonAudioURL)会抛出异常。所以你需要添加异常处理代码。

 do {
        try buttonAudioPlayer = AVAudioPlayer(contentsOfURL: buttonAudioURL)
    } catch {
        //handle exception here
    }

Swift ERROR : : Call can throw, but it is not marked with 'try' and the error is not handled

Swift ERROR : : Call can throw, but it is not marked with 'try' and the error is not handled

avfoundation

ios

swift