AVAudioPlayer按下手势识别器时不会播放声音

Question

我正在创建一个flashcard应用程序。现在我正处于可以左右扫描每张图像的地步。每个图像都有一个与之关联的声音文件。点击图像时，与其关联的声音文件应播放。到目前为止，我可以通过图像轻扫，但是当我点击图像时没有声音播放。下面的代码。

import UIKit 

class SecondViewController: UIViewController , UIGestureRecognizerDelegate { 



var imageIndex: Int = 0 
@IBAction func home(_ sender: Any) { 
    performSegue(withIdentifier: "home", sender: self) 
} 

@IBOutlet weak var imgPhoto: UIImageView! 


let itemList:[Card] = [ 
    Card(image: UIImage(named: "alligator")!, soundUrl: "Alligator.m4a"), 
    Card(image: UIImage(named: "apple")!, soundUrl: "Apple.m4a"), 
    Card(image: UIImage(named: "ball")!, soundUrl: "Ball.m4a") 
] 



override func viewDidLoad() { 
    super.viewDidLoad() 


    let tapGestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(imageTapped(tapGestureRecognizer:))) 
    imgPhoto.isUserInteractionEnabled = true 
    imgPhoto.addGestureRecognizer(tapGestureRecognizer) 

    imgPhoto.image = (itemList[0]).image 

    // Do any additional setup after loading the view. 
    imgPhoto.isUserInteractionEnabled = true 

    let leftSwipe = UISwipeGestureRecognizer(target: self, action: #selector(Swiped(gesture:))) 
    leftSwipe.cancelsTouchesInView = false 

    let rightSwipe = UISwipeGestureRecognizer(target: self, action: #selector(Swiped(gesture:))) 
    rightSwipe.cancelsTouchesInView = false 

    leftSwipe.direction = .left 
    rightSwipe.direction = .right 


    view.addGestureRecognizer(leftSwipe) 
    view.addGestureRecognizer(rightSwipe) 

} 

    @IBAction func imageTapped(tapGestureRecognizer: UITapGestureRecognizer) 
{ 
    print("hhh") 
    itemList[imageIndex].playSound() 
    // Your action 
} 

func Swiped(gesture: UIGestureRecognizer) { 

    if let swipeGesture = gesture as? UISwipeGestureRecognizer { 

     switch swipeGesture.direction { 

     case UISwipeGestureRecognizerDirection.right : 
      print("User swiped right") 

      // decrease index first 

      imageIndex -= 1 

      // check if index is in range 

      if imageIndex < 0 { 

       imageIndex = itemList.count - 1 

      } 

      imgPhoto.image = itemList[imageIndex].image 

     case UISwipeGestureRecognizerDirection.left: 
      print("User swiped Left") 
      // increase index first 

      imageIndex += 1 

      // check if index is in range 

      if imageIndex > itemList.count - 1 { 

       imageIndex = 0 

      } 



      imgPhoto.image = itemList[imageIndex].image 
     default: 


      break //stops the code/codes nothing. 
     } 
    } 
} 
} 

然后我有另一个有AVAudioPlayer代码的类，并且给出了每个“Card”（下面的代码）的定义。

import Foundation; import UIKit; import AVFoundation 

var player: AVAudioPlayer? 

class Card: NSObject 
{ 
var image: UIImage 
var soundUrl: String 


init(image: UIImage, soundUrl: String) { 
    self.image = image 
    self.soundUrl = soundUrl 
} 
func playSound() 
{ 
    guard let url = Bundle.main.url(forResource: self.soundUrl, withExtension: "m4a") else { return } 
    do 
    { 
     try AVAudioSession.sharedInstance().setCategory(AVAudioSessionCategoryPlayback) 
     try AVAudioSession.sharedInstance().setActive(true) 

     player = try AVAudioPlayer(contentsOf: url) 
     guard let player = player else { return } 
     player.prepareToPlay() 
     player.play() 
    print("play") 
    } catch let error { 
     print(error.localizedDescription) 
    } 
} 
} 

该代码编译没有错误，但没有播放声音。当我点击屏幕时程序确实打印了一行，但是我没有从播放声音功能中打印任何行，这意味着该部分代码没有被执行。我已经把var player：AVAudioPlayer？在班级之外推荐，但仍然没有运气。我已经添加了AVAudioPlayer框架，所以这也不是问题。

Answer 1

我认为问题出在你的扩展，你给了错误的分机在

guard let url = Bundle.main.url(forResource: self.soundUrl, withExtension: "m4a") 

，并在此不需要扩展

Card(image: UIImage(named: "alligator")!, soundUrl: "Alligator"), 
    Card(image: UIImage(named: "apple")!, soundUrl: "Apple"), 
    Card(image: UIImage(named: "ball")!, soundUrl: "Ball") 

更改扩展名与您的文件扩展名为.MP4

Answer 2

你要删除的文件扩展名是：

let itemList:[Card] = [ 
    Card(image: UIImage(named: "alligator")!, soundUrl: "Alligator"), 
    Card(image: UIImage(named: "apple")!, soundUrl: "Apple"), 
    Card(image: UIImage(named: "ball")!, soundUrl: "Ball") 
] 

，因为你在func playSound()功能

guard let url = Bundle.main.url(forResource: self.soundUrl, withExtension: "m4a") else { return } 

func playSound() { 
    guard let url = Bundle.main.url(forResource: self.soundUrl, withExtension: "m4a") else { return } 

    do { 
     try AVAudioSession.sharedInstance().setCategory(AVAudioSessionCategoryPlayback) 
     try AVAudioSession.sharedInstance().setActive(true) 

     player = try AVAudioPlayer(contentsOf: url) 
     guard let player = player else { return } 
     player.prepareToPlay() 
     player.play() 
    } catch let error { 
     print(error.localizedDescription) 
    } 
} 

添加扩展，使这是加双扩展到您的文件名是不在你的软件包中可用。

注意：请确保您的文件名和扩展名与您的软件包文件名相同。 该文件需要正确导入（项目构建阶段>复制包资源）。

Answer 3

我认为问题是由于NSDefaultRunLoopMode造成，其中两个事件同时运行。当我以毫秒为单位更新标签时，我遇到了这个NSDefaultRunLoopMode的问题。在打开键盘时，它并没有在那个时间更新。然后为了解决这个问题我在NSRunLoopCommonModes中运行该计时器。我不知道它是否会在你的情况下工作，但仍然可以共享，如果它可以帮助你。