带小数点的 PickerView

Question

我使用了一个带有四个组件的 UIPickerView 来在没有键盘的情况下输入数字。我添加了一个小数点，只有一个“。”在 UILabelView 中。查看屏幕了解想法。

我的 UIPickerView 代码是：

func numberOfComponents(in weightPickerView: UIPickerView) -> Int {
    return 4
}

func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
    return loopingMargin * numbers.count
}

func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
  return numbers[row % numbers.count]
}

func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
    let currentIndex = row % numbers.count
    digits[component] = currentIndex
    let weightString = "\(digits[0])\(digits[1]).\(digits[2])\(digits[3])"
    weightField.text = weightString
}

在 viewDidLoad() 中，部分代码是：

override func viewDidLoad() {
    super.viewDidLoad()        
    // Do any additional setup after loading the view.

    weightPickerView.dataSource = self
    weightPickerView.delegate = self
    weightPickerView.selectRow((loopingMargin / 2) * numbers.count, inComponent: 0, animated: false)
    weightPickerView.selectRow((loopingMargin / 2) * numbers.count, inComponent: 1, animated: false)
    weightPickerView.selectRow((loopingMargin / 2) * numbers.count, inComponent: 2, animated: false)
    weightPickerView.selectRow((loopingMargin / 2) * numbers.count, inComponent: 3, animated: false)

}

我的问题...我想添加第五个组件，其中只有一个“.”。在其中（因此 space 得到均匀分布）。我该怎么做？

Answer 1

你可以试试

func numberOfComponents(in weightPickerView: UIPickerView) -> Int {
    return 5
}


 func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
   if(component == 2)
   {
      return "."
   }
   else
   {
       return numbers[row % numbers.count]
   }
}

Answer 2

您只需更新选择器视图方法即可提供额外的组件。假设你想要它在中间，你的代码需要是：

func numberOfComponents(in weightPickerView: UIPickerView) -> Int {
    return 5
}

func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
    return component == 2 ? 1 : loopingMargin * numbers.count
}

func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
  return component == 2 ? "." : numbers[row % numbers.count]
}

func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
    if component != 2 {
        var index = component
        if component > 2 {
            index -= 1
        }
        let currentIndex = row % numbers.count
        digits[index] = currentIndex
        let weightString = "\(digits[0])\(digits[1]).\(digits[2])\(digits[3])"
        weightField.text = weightString
    }
}

override func viewDidLoad() {
    super.viewDidLoad()        

    weightPickerView.dataSource = self
    weightPickerView.delegate = self
    weightPickerView.selectRow((loopingMargin / 2) * numbers.count, inComponent: 0, animated: false)
    weightPickerView.selectRow((loopingMargin / 2) * numbers.count, inComponent: 1, animated: false)
    weightPickerView.selectRow((loopingMargin / 2) * numbers.count, inComponent: 3, animated: false)
    weightPickerView.selectRow((loopingMargin / 2) * numbers.count, inComponent: 4, animated: false)
}

假设 . 代表小数点分隔符，请记住，世界各地的许多用户并不使用 . 作为小数点分隔符。所以你真的应该表现出合适的性格。您可以获得 decimalSeparator 属性的 NumberFormatter.

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