AVFoundation Swift Error

Question

我试图为我的游戏创建一些背景音乐，我得到以下错误与我的代码:

import SpriteKit
import AVFoundation
    class GameScene: SKScene {
    let ballCategoryName = "ball"
    let paddCategoryName = "paddle"
    let brickCategoryName = "brick"
    let backgroundMusicPlayer = AVAudioPlayer()
    override init(size: CGSize){
        super.init(size: size)
        let bgMusicURL = NSBundle.mainBundle().URLForResource("bgMusic", withExtension: "mp3")
        backgroundMusicPlayer = AVAudioPlayer(contentsOfURL: bgMusicURL, error: nil);
        backgroundMusicPlayer.numberOfLoops = -1

    }
    required init?(coder aDecoder: NSCoder){
        super.init(coder: aDecoder)
    }
}

错误在行:

backgroundMusicPlayer = AVAudioPlayer(contentsOfURL: bgMusicURL, error: nil)

如何修复这个错误?它说不能在self中分配backgroundmusicplayer。mp3的名称也和代码中一样

Answer 1

你的backgroundMusicPlayer是一个let常量:

let backgroundMusicPlayer = AVAudioPlayer()

如果您想改变该变量，将let更改为var。