swift - 在 Swift 浮点值和 "X": Polloquin Exercise Notation 中创建类型

Question

我正在尝试编写举重时间。重复有四个阶段:

偏心(降低重量所花费的时间)底部(在电梯底部花费的时间)同心(举重所花费的时间)顶部(电梯顶部花费的时间)

其格式如下:1030

因此，在该示例中，一个人需要 1 秒的时间放下重物，然后立即花 3 秒的时间举起重物，到达 Action 终点并停下来完成一次重复。

class rep {

    var eccentric:Float //  time spent lowering the weight
    var bottom:Float // time spent at the bottom of the repetition.
    var concentric:Float  // time spent raising the weight.
    var top:Float // time spent at the top of the repetition.

    var notation:String

    init(timeDown:Float, timeBottom:Float, timeUp:Float, timeTop:Float)        {

    eccentric = timeDown
    bottom = timeBottom
    concentric = timeUp
    top = timeTop

    notation = "\(eccentric),\(bottom),\(concentric),\(top)"

}

func displayNotation() -> String{

    print(notation)

    return notation

    }

}





class ViewController: UIViewController {

override func viewDidLoad() {
    super.viewDidLoad()


   let repetition = rep(timeDown: 1,timeBottom: 0,timeUp: 3,timeTop: 0)

  repetition.displayNotation()



}

输出 1.0,0.0,3.0,0.0

我想要做的是添加一个字符“X”来表示“尽快”。我在想我需要为此创建一个新类型吗？所以我希望能够接受一个 float 或那个特定的字符......完全困惑于如何去做。

感谢您的回复

Answer 1

好的，这是解决这个问题的一种方法。

首先为您的数据创建一个模型:

class Data {
    var string: String
    var value: Double?

    init(string: String, value: Double?) {
        self.string = string
        self.value = value
    }
}

字符串将用于显示，值将用于计算。我将 value 设置为可选值，稍后将对此进行解释。

<小时/>

然后为 UIPickerView 创建数据源并填充它:

var dataSource: [Data] = []

// Adds all values from 0.0 to 9.9 and the "additional character".
func populateDataSource() {
    for i in 0..<100 {
        let value = Double(i) / 10
        dataSource.append(Data(string: value.description, value: value))
    }
    dataSource.append(Data(string: "X", value: nil))
}

我在这里所做的是将附加字符的值设置为nil。

<小时/>

假设您已经配置了 UIPickerView，请添加 UIPickerViewDataSource 方法:

func numberOfComponentsInPickerView(pickerView: UIPickerView) -> Int {
    return 1
}

func pickerView(pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
    return dataSource.count
}

func pickerView(pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
    return dataSource[row].string
}

// This variable will be used to hold the user selection.
var selected: Data?

// If you want it to default to e.g. 0.0, just create it as:
// var selected = dataSource.first

func pickerView(pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
    self.selected = dataSource[row]
}

<小时/>

现在您可以根据选择进行计算:

// You should check that selection isn't nil before doing this.
// Depends on how you create it.

if let value = selection.value {
    // The selection has a value between 0.0 and 9.9.
    // So, do your standard calculations for that.
} else {
    // The selection does not have a value, which means it's your custom character.
    // So, take that into account in your calculations.
}