Question

我正在制作Flappy Bird型游戏，我想在收集硬币时添加声音效果。这就是我所拥有的：

import SpriteKit
import AVFoundation

class GameScene: SKScene {

    var coinSound = NSURL(fileURLWithPath:NSBundle.mainBundle().pathForResource("Super Mario Bros.- Coin Sound Effect", ofType: "mp3")!)
    var audioPlayer = AVAudioPlayer()

稍后在我的didMoveToView中：

audioPlayer = AVAudioPlayer(contentsOfURL: coinSound, error: nil)
audioPlayer.prepareToPlay()

对于第二部分（在我的didMoveToView中），第一行继续显示错误：

调用可以抛出，但没有标记为'try'并且未处理错误

我该如何解决这个问题？

Answer 1

我知道你已经标记了一个答案，但是如果你读过这个问题，或者对于未来的读者来说，更容易使用SKActions来播放短暂的1次声音。

AVFoundation最适合用于背景音乐。

例如

class GameScene: SKScene {

     // add as class property so sound is preloaded and always ready
     let coinSound = SKAction.playSoundFileNamed("NAMEOFSOUNDFILE", waitForCompletion: false)
}

而且当你需要播放声音时，只需说出这个

run(coinSound)

希望这有帮助

Answer 2

audioPlayer = AVAudioPlayer(contentsOfURL: coinSound, error: nil)

这不再是Swift中处理错误的方式。您必须使用do-try-catch语法。

do {
    audioPlayer = try AVAudioPlayer(contentsOfURL: coinSound)
    audioPlayer.prepareToPlay()
}
catch let error {
    // handle error
}

或者，如果您不打算编写任何错误处理代码，可以将audioPlayer变量设为可选，并编写一个可用的try?：

audioPlayer = try? AVAudioPlayer(contentsOfURL: coinSound)
audioPlayer?.prepareToPlay()

这更接近于您在为{error}参数传递nil时尝试的代码。

或者，如果发生错误时崩溃是适当的行为，您可以采用这种方法：

guard let audioPlayer = try? AVAudioPlayer(contentsOfURL: coinSound) else {
    fatalError("Failed to initialize the audio player with asset: \(coinSound)")
}
audioPlayer.prepareToPlay()
self.audioPlayer = audioPlayer

Answer 3

Swift 3.0 +

对于@nhgrif的上述guard let示例，这种Swift 3.0+方式：

var coinSound = NSURL(fileURLWithPath:Bundle.main.path(forResource: "Super Mario Bros.- Coin Sound Effect", ofType: "mp3")!)
var audioPlayer = AVAudioPlayer()

func playCoinSound(){
    guard let soundToPlay = try? AVAudioPlayer(contentsOf: coinSound as URL) else {
        fatalError("Failed to initialize the audio player with asset: \(coinSound)")
    }
    soundToPlay.prepareToPlay()

//  soundToPlay.play() // NO IDEA WHY THIS DOES NOT WORK!!!???

    self.audioPlayer = soundToPlay
    self.audioPlayer.play() // But this does work... please let me know why???
}

playCoinSound()

在Spritekit中添加声音效果

3 个答案:

Swift 3.0 +