Question

我通过设置AVAudioPlayer值来快速转发rate。但是我无法弄清楚如何倒带。

我正在制作一个DJ应用，音乐的播放rate在旋转转盘时发生变化，导致音乐快进和快退（同时仍然听到声音）。

这是我目前转盘旋转的方法。如何回放AVAudioPlayer？

 override func touchesMoved(touches: Set<UITouch>, withEvent event: UIEvent?) {

for touch in touches {
    let location = touch.locationInNode(self)
    let node = self.nodeAtPoint(location)


    //this is for the left turntable
    if node.name == "lefttt" {

        //lets user rotate left turntable when there is one finger on turntable.
        let dy = leftTurntable.position.y - location.y
        let dx = leftTurntable.position.x - location.x
        let angle2 = atan2(dy, dx)
        leftTurntable.zRotation = angle2


        let delta = (angle2 - previousAngle)
        if delta > 0 {

            // Code to rewind music goes here....
            print("rotateleft")


        } else {
            //This code works perfectly and fast forwards the music when spinning turntable to right
            print("rotateright")
            musicPlayer.rate = 2.0
            musicPlayer.play()
        }

        previousAngle = angle2
 }

Answer 1

您可以通过将public class CustomerCollectionValidator: CompositeValidator<CustomerCollection> { public CustomerCollectionValidator() { RuleFor(x => x.ListOfCustomers) .Must(ShouldHaveOneSurName) .WithMessage("Should have one Surname in list"); RuleForEach(x => x.ListOfCustomers).SetValidator<CustomerValidator>(); } public bool ShouldHaveOneSurName(List<Customer> lstCustomers) { if (lstCustomers== null) { return false; } return lstCustomers.Any(x => !String.IsNullOrWhiteSpace(x.SurName); } }设置为小于其当前值的值来回放。

我认为这不会以某种听觉的方式回放。你不会神奇地听到音乐倒退或类似的东西。 AVAudioPlayer不这样做。但是，它会改变比赛位置，这样当你再次开始比赛（前锋）时，你将比你现在更早开始。

AVPlayer（与AVAudioPlayer相对）可以反向播放，但仅限于特定的AVPlayerItem允许的情况。

有没有办法在Swift中使用rate属性来回放音乐？

1 个答案: