Question

我有背景音乐，当使用以下代码在GameViewController.swift中启动应用程序时启动：

class GameViewController: UIViewController {

// VARIABLES
var backgroundMusicPlayer : AVAudioPlayer!

// AUDIO PLAYER
func playBackgroundMusic(filename: String) {
    let url = NSBundle.mainBundle().URLForResource(filename, withExtension: nil)
    var error : NSError? = nil
    do {
        backgroundMusicPlayer = try AVAudioPlayer(contentsOfURL: url!)
    } catch let error1 as NSError {
        error = error1
        backgroundMusicPlayer = nil
    }
    if backgroundMusicPlayer == nil {
        print("Could not create audio player: \(error!)")
        return
    }
    backgroundMusicPlayer.numberOfLoops = -1
    backgroundMusicPlayer.prepareToPlay()
    backgroundMusicPlayer.play()
}

func stopBackgroundMusic() {
    backgroundMusicPlayer.stop()
}

override func viewDidLoad() {
    super.viewDidLoad()
    playBackgroundMusic("MainTheme.mp3")

<< Various irrelevant code >>
}

因为这是在viewController中运行的，所以它会通过改变菜单上的场景（即打开“商店”场景）而持续存在并创建无缝轨道。当我点击菜单场景中的“播放”按钮时，我希望音乐停止，然后转换到游戏。我在GameViewController中有stopBackgroundMusic（）方法，但我不知道如何在菜单场景中调用它。 在菜单场景中我尝试了这个：

// TOUCH
override func touchesBegan(touches: Set<UITouch>, withEvent event: UIEvent?) {
    let touch = touches.first as UITouch?
    let touchLocation = touch!.locationInNode(self)
    let touchedNode = self.nodeAtPoint(touchLocation)
    if touchedNode.name == "startGame" {
        GameViewController.stopBackgroundMusic()
        let transitionType = SKTransition.fadeWithDuration(2)
        let viewSize = self.view?.bounds.size
        let scene = GameScene(size: viewSize!)
        self.view?.presentScene(scene, transition: transitionType)
    }
}

但是我得到一个错误，说我在调用stopBackgroundMusic（）时缺少参数＃1，它不需要任何参数。我称这种方法错了吗？谢谢！

Answer 1

您通过使用GameViewController引用您的类，但您的函数位于对象实例级别。

如果在类级别声明变量和函数，touchesBegan函数中的代码应该可以正常工作。

static var backgroundMusicPlayer : AVAudioPlayer!
class func playBackgroundMusic(filename: String) ...
class func stopBackgroundMusic()

override func viewDidLoad() {
   super.viewDidLoad()
   GameViewController.playBackgroundMusic("MainTheme.mp3")

  << Various irrelevant code >>
}

开始游戏时停止背景音乐

1 个答案: