Question

我正在尝试创建一个简单的控制器，该控制器将在用户每次单击按钮时为您提供每分钟的节拍。我的代码编译成功，但是由于某些原因未调用button动作内的代码。对我做错的任何想法吗？

import Foundation
import UIKit

class taptempo: UIViewController {


    private var timeOutInterval = 5.0
    private var minTaps = 3
    private var taps: [NSDate] = []

    var calculatedbpm = 0

    var timeOut = 5
    var minimumTaps = 3

    @IBOutlet weak var tapnumberlabel: UILabel!
    @IBOutlet weak var tapnumberbutton: UIButton!

    override func viewDidLoad(){
        super.viewDidLoad()

        self.tapnumberlabel.text = "\(calculatedbpm)"

    }

    @IBAction func tapnumberbutaction(_ sender: Any) {

        func addTap() -> Int? {
            let thisTap = NSDate()
            if let lastTap = taps.last {
                if thisTap.timeIntervalSince(lastTap as Date) > timeOutInterval {
                    taps.removeAll()
                }
            }
            taps.append(thisTap)
            guard taps.count >= minTaps else { return nil }
            guard let firstTap = taps.first else { return 0 }
            let avgIntervals = thisTap.timeIntervalSince(firstTap as Date) / Double(taps.count - 1)
            calculatedbpm = Int((60.0 / avgIntervals))
            self.tapnumberlabel.text = "\(calculatedbpm)"
            print(calculatedbpm)
            return calculatedbpm

           // print("func not working")
        }
    }
}

Answer 1

您需要定义一个函数，该函数可以在函数主体外部计算bmp。然后在按钮操作中调用它并更新ui。

@IBAction func tapnumberbutaction(_ sender: Any) {
    self.tapnumberlabel.text = "\(addTap() ?? 0)" // conditional unwrap of returned value
}

func addTap() -> Int? {
    let thisTap = NSDate()
    if let lastTap = taps.last {
        if thisTap.timeIntervalSince(lastTap as Date) > timeOutInterval {
            taps.removeAll()
        }
    }
    taps.append(thisTap)
    guard taps.count >= minTaps else { return nil }
    guard let firstTap = taps.first else { return 0 }
    let avgIntervals = thisTap.timeIntervalSince(firstTap as Date) / Double(taps.count - 1)
    calculatedbpm = Int((60.0 / avgIntervals))
    print(calculatedbpm)
    return calculatedbpm
}

Answer 2

在按钮动作之外编写addTap（）函数。然后从按钮的Action调用addTap（）函数。

func addTap() -> Int? {

        let thisTap = NSDate()
        if let lastTap = taps.last {
            if thisTap.timeIntervalSince(lastTap as Date) > timeOutInterval {
                taps.removeAll()
            }
        }
        taps.append(thisTap)
        guard taps.count >= minTaps else { return nil }
        guard let firstTap = taps.first else { return 0 }
        let avgIntervals = thisTap.timeIntervalSince(firstTap as Date) / Double(taps.count - 1)
        calculatedbpm = Int((60.0 / avgIntervals))
        return calculatedbpm

       // print("func is working")
    }

 @IBAction func tapnumberbutaction(_ sender: Any) {

     self.tapnumberlabel.text = String(addTap())                             
  }

点击按钮以执行bpm代码

2 个答案: