声音返回 Swift

Question

我可以在单击按钮时播放声音。我可以找到这个并且它与游戏配合得很好：

var sound1 = AVAudioPlayer()
func setupAudioPlayerWithFile(file:NSString, type:NSString) -> AVAudioPlayer  {
    var path = NSBundle.mainBundle().pathForResource(file as String, ofType: type as String)
    var url = NSURL.fileURLWithPath(path!)
    var error: NSError?
    var audioPlayer:AVAudioPlayer?
    audioPlayer = AVAudioPlayer(contentsOfURL: url, error: &error)
    return audioPlayer!
}
@IBAction func play(sender: AnyObject) {
    soun1.play()
}

在 viewDidLoad 中：

sound1 = self.setupAudioPlayerWithFile("NameAudioFile", type:"mp3")

如何从当前时间返回 30 秒？

@IBAction func back(sender: AnyObject) {
    ...
}

Answer 1

您可以使用 Swift 三元条件运算符 '?'您检查 currentTime 是否 > 30 ？如果为真减去 30 ：否则等于 0

sound1.currentTime = sound1.currentTime > 30.0 ? sound1.currentTime - 30.0 : 0

编辑

正如 OP 所指出的，只需从 currentTime 中减去 30s，因为它将负值视为零：

sound1.currentTime = sound1.currentTime - 30.0

Ternary conditional operator

The ternary conditional operator is a special operator with three parts, which takes the form question ? answer1 : answer2. It is a shortcut for evaluating one of two expressions based on whether question is true or false. If question is true, it evaluates answer1 and returns its value; otherwise, it evaluates answer2 and returns its value.

声音返回 Swift

Sound go back with Swift

audio

swift