我创建了一个应用程序，我试图让用户在玩游戏时继续听他们的音乐，但每当他们点击“播放”并且发出游戏声音时它将停止背景音乐。我正在使用Swift在iOS上进行开发。这是启动游戏声音的一段代码。
func playSpawnedDot() {
var alertSound: NSURL = NSURL(fileURLWithPath: NSBundle.mainBundle().pathForResource("spawnDot", ofType: "mp3")!)!
var error:NSError?
audioPlayer = AVAudioPlayer(contentsOfURL: alertSound, error: &error)
audioPlayer.prepareToPlay()
if volumeBool {
audioPlayer.play()
}
}
您需要使用以下值之一设置AVAudioSession类别：https://developer.apple.com/library/ios/documentation/AVFoundation/Reference/AVAudioSession_ClassReference/index.html（AVAudioSession类参考）。
默认值设置为AVAudioSessionCategorySoloAmbient。你可以读到：
[...]使用此类别意味着您的应用程序的音频不可混合 - 激活您的会话将中断任何其他也不可混合的音频会话。要允许混音，请改用
AVAudioSessionCategoryAmbient类别。
在播放声音之前，您必须更改类别。为此：
AVAudioSession.sharedInstance().setCategory(AVAudioSessionCategoryAmbient, error: nil)
AVAudioSession.sharedInstance().setActive(true, error: nil)
每次播放声音时都不需要调用这些行。您可能只想做一次。
我不认为只是将AVAudioSession设置为AVAudioSessionCategoryOptions.duckOthers就行了，但确实如此。这是我完整的代码，以帮助像我这样的新秀。
Swift 4 - 完整示例：
var audioPlayer = AVAudioPlayer()
func playSound(sound: String){
let path = Bundle.main.path(forResource: sound, ofType: nil)!
let url = URL(fileURLWithPath: path)
let audioSession = AVAudioSession.sharedInstance()
try!audioSession.setCategory(AVAudioSessionCategoryPlayback, with: AVAudioSessionCategoryOptions.duckOthers)
do {
audioPlayer = try AVAudioPlayer(contentsOf: url)
audioPlayer.play()
} catch {
print("couldn't load the file")
}
}
我仍然需要弄清楚setActive（I was looking at this blog post）但是当我离开应用程序时音频停止闪避，所以它适用于我的应用程序。
Swift 4版本：
try? AVAudioSession.sharedInstance().setCategory(AVAudioSessionCategoryAmbient)
try? AVAudioSession.sharedInstance().setActive(true)
这就是我在Swift 3.0中的表现
var songPlayer : AVAudioPlayer?
func SetUpSound() {
if let path = Bundle.main.path(forResource: "TestSound", ofType: "wav") {
let filePath = NSURL(fileURLWithPath:path)
songPlayer = try! AVAudioPlayer.init(contentsOf: filePath as URL)
songPlayer?.numberOfLoops = -1 //logic for infinite loop
songPlayer?.prepareToPlay()
songPlayer?.play()
}
let audioSession = AVAudioSession.sharedInstance()
try!audioSession.setCategory(AVAudioSessionCategoryPlayback, with: AVAudioSessionCategoryOptions.duckOthers) //Causes audio from other sessions to be ducked (reduced in volume) while audio from this session plays
}
你可以在这里看到更多的AVAudioSessionCategoryOptions：https://developer.apple.com/reference/avfoundation/avaudiosessioncategoryoptions
这是我用于Swift 2.0的内容：
let sess = AVAudioSession.sharedInstance()
if sess.otherAudioPlaying {
_ = try? sess.setCategory(AVAudioSessionCategoryAmbient, withOptions: .DuckOthers)
_ = try? sess.setActive(true, withOptions: [])
}
请注意，如果你不想降低背景音乐而不是在它上面播放，你可以用.DuckOthers替换[]。
lchamp的解决方案非常适合我，适用于Objective-C：
[[AVAudioSession sharedInstance] setCategory:AVAudioSessionCategoryAmbient error:nil];
[[AVAudioSession sharedInstance] setActive:YES error:nil];
**
**
我正在播放的声音的名称是shatter.wav
func shatterSound() {
if let soundURL = Bundle.main.url(forResource: "shatter", withExtension: "wav") {
var mySound: SystemSoundID = 0
AudioServicesCreateSystemSoundID(soundURL as CFURL, &mySound)
AudioServicesPlaySystemSound(mySound);
}
}
然后你想在哪里播放声音
shatterSound()
如果你想播放警报声：
public func playSound(withFileName fileName: String) {
if let soundUrl = Bundle.main.url(forResource: fileName, withExtension: "wav") {
do {
try AVAudioSession.sharedInstance().setCategory(AVAudioSessionCategoryAmbient, with:[.duckOthers])
try AVAudioSession.sharedInstance().setActive(true)
var soundId: SystemSoundID = 0
AudioServicesCreateSystemSoundID(soundUrl as CFURL, &soundId)
AudioServicesAddSystemSoundCompletion(soundId, nil, nil, { (soundId, clientData) -> Void in
AudioServicesDisposeSystemSoundID(soundId)
do {
// This is to unduck others, make other playing sounds go back up in volume
try AVAudioSession.sharedInstance().setActive(false)
} catch {
DDLogWarn("Failed to set AVAudioSession to inactive. error=\(error)")
}
}, nil)
AudioServicesPlaySystemSound(soundId)
} catch {
DDLogWarn("Failed to create audio player. soundUrl=\(soundUrl) error=\(error)")
}
} else {
DDLogWarn("Sound file not found in app bundle. fileName=\(fileName)")
}
}
如果你想播放音乐：
导入AVFoundation
var audioPlayer:AVAudioPlayer?
public func playSound(withFileName fileName: String) {
if let soundUrl = Bundle.main.url(forResource: fileName, withExtension: "wav") {
do {
try AVAudioSession.sharedInstance().setCategory(AVAudioSessionCategoryAmbient, with:[.duckOthers])
try AVAudioSession.sharedInstance().setActive(true)
let player = try AVAudioPlayer(contentsOf: soundUrl)
player.delegate = self
player.prepareToPlay()
DDLogInfo("Playing sound. soundUrl=\(soundUrl)")
player.play()
// ensure the player does not get deleted while playing the sound
self.audioPlayer = player
} catch {
DDLogWarn("Failed to create audio player. soundUrl=\(soundUrl) error=\(error)")
}
} else {
DDLogWarn("Sound file not found in app bundle. fileName=\(fileName)")
}
}
func audioPlayerDidFinishPlaying(_ player: AVAudioPlayer, successfully flag: Bool) {
self.audioPlayer?.stop()
do {
// This is to unduck others, make other playing sounds go back up in volume
try AVAudioSession.sharedInstance().setActive(false)
} catch {
DDLogWarn("Failed to set AVAudioSession inactive. error=\(error)")
}
}
对于Swift（Objective-C也是如此）
你可以使用this链接获得最佳答案，如果你没有任何时间观看10分钟，最好的动作是你只需要在copy的AppDelegate下面的didFinishLaunchingWithOptions代码，然后选择你的project's target然后去Capabilities，最后在Background modes检查Audio, AirPlay and Picture in Picture
func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
// Override point for customization after application launch.
let session = AVAudioSession.sharedInstance()
do {
try session.setCategory(AVAudioSessionCategoryPlayback)
}
catch {
}
}
因为他们似乎无法从版本到版本做出决定。这是在Swift 5.0中
do{
try AVAudioSession.sharedInstance().setCategory(.ambient)
try AVAudioSession.sharedInstance().setActive(true, options: .notifyOthersOnDeactivation)
} catch {
NSLog(error.localizedDescription)
}