ios - 如何用swift 2.0播放背景音乐？

Question

嗨，我是 swift 和 ios 开发的新手。在我更新到 Swift 2.0 之前，我的代码一直在运行，我使用了快速迁移工具，但我仍然不知道如何整理和修复我的代码。请帮忙!

import AVFoundation

var backgroundMusicP: AVAudioPlayer!

func playBackgroundMusic(filename: String) {
    let url = NSBundle.mainBundle().URLForResource(
        filename, withExtension: nil)
    if (url == nil) {
        print("Could not find file: \(filename)")
        return
    }

    var error: NSError?

    do {

        backgroundMusicP = try AVAudioPlayer(contentsOfURL: url!)
    } catch {

        backgroundMusicP == nil
    }
    if backgroundMusicP == nil {
        print("Could not create audio player: \(error)")
        return
    }

    backgroundMusicP.numberOfLoops = -1
    backgroundMusicP.prepareToPlay()
    backgroundMusicP.play()
}

Answer 1

swift 2.0 的更新函数:

import AVFoundation

var backgroundMusicPlayer = AVAudioPlayer()

func playBackgroundMusic(filename: String) {
    let url = NSBundle.mainBundle().URLForResource(filename, withExtension: nil)
    guard let newURL = url else {
        print("Could not find file: \(filename)")
        return
    }
    do {
        backgroundMusicPlayer = try AVAudioPlayer(contentsOfURL: newURL)
        backgroundMusicPlayer.numberOfLoops = -1
        backgroundMusicPlayer.prepareToPlay()
        backgroundMusicPlayer.play()
    } catch let error as NSError {
        print(error.description)
    }
}

这样使用:

playBackgroundMusic("yourFileName.mp3")