使用iOS上的音量按钮向上和向下计数（Swift）

Question

您好我为自己创建了一个应用程序，我想要计算并在屏幕上显示＃。我想使用音量按钮向上和向下计数。我能够在屏幕上创建一个按钮来上下计数，但我想使用物理按钮。我列出了到目前为止我所拥有的内容，但音量按钮似乎无法正常工作。我已经用AVAudioPlayer取代AVAudioSession，希望用滑块控制音量。 我收到错误EXC_BAD_ACCESS（代码= 1，地址= 0x48）

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 import UIKit
import AVFoundation

class ViewController: UIViewController {
    
    var audioPlayer = AVAudioPlayer()
    
    @IBOutlet weak var counter: UILabel!
    @IBOutlet weak var tapCounterUp: UIButton!
    @IBOutlet weak var tapCounterDown: UIButton!
    @IBOutlet weak var tapReset: UIButton!

    @IBOutlet weak var volumeController: UISlider!

    
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.

    }

    

    //Starts the count at 0
   var count : Int = 0
    
    
    //Adds +1 to Count
    @IBAction func buttonUp(_ sender: Any) {
        count += 1
        counter.text = String(count)
    }
    
    //Subtracts -1 to Count
    @IBAction func buttonDown(_ sender: Any) {
        count -= 1
        counter.text = String(count)
    }
    
    //Resets the Count to "0"
    @IBAction func buttonReset(_ sender: Any) {
        count = 0
        counter.text = String(count)
    }
    
    
   //Volume Controller
    @IBAction func volumeControl(_ sender: UISlider) {
        
        let sliderValue = lroundf(sender.value)
        
        counter.text = "\(sliderValue)"

**// This is were the Error occurs.**
        
        audioPlayer.volume = volumeController.value
        
        
    }


    
    
    
 // End of funtion, don't delete
}

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