故事板日期选择器中的选择性日期（iOS 开发）

Question

是否可以在 iOS 故事板中将 DatePicker 限制为具有给定范围的选择性日期？ 我正在尝试让 DatePicker 仅在星期六显示。

Answer 1

您无法在 Storyboard 中执行此操作，也无法使用 UIDatePicker...

但是，使用UIPickerView 非常简单。

• 获取“本周六”的日期
• 对于每一行，返回 thisSaturday plus（7 x 行）

这是一个简单的例子：

class ViewController: UIViewController, UIPickerViewDataSource, UIPickerViewDelegate {
    
    let picker = UIPickerView()
    let dateFormatter = DateFormatter()
    
    var thisSaturday: Date!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        // set your desired date format
        dateFormatter.dateStyle = .medium
        
        picker.translatesAutoresizingMaskIntoConstraints = false
        view.addSubview(picker)
        
        let g = view.safeAreaLayoutGuide
        
        NSLayoutConstraint.activate([

            // center picker view with default width and height
            picker.centerXAnchor.constraint(equalTo: g.centerXAnchor),
            picker.centerYAnchor.constraint(equalTo: g.centerYAnchor),
            
        ])
        
        picker.dataSource = self
        picker.delegate = self

        // get the date for the "upcoming Saturday"
        
        let today = Date()
        let daysToAdd = 7 - (Calendar.current.dateComponents([.weekday], from: today).weekday ?? 0 )
        guard let d = Calendar.current.date(byAdding: .day, value: daysToAdd, to: today) else {
            fatalError("Could not get a valid date!!! (This should never happen...)")
        }

        thisSaturday = d

    }
    
    func numberOfComponents(in pickerView: UIPickerView) -> Int {
        return 1
    }
    
    func pickerView(_ pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
        // how many weeks in the future do you want to allow?
        //  for example, 52-weeks x 4-years
        return 52 * 4
    }
    
    func pickerView(_ pickerView: UIPickerView, titleForRow row: Int, forComponent component: Int) -> String? {
        // each row will be
        //  "upcoming Saturday" plus
        //  7-days x row number
        guard let d = Calendar.current.date(byAdding: .day, value: 7 * row, to: thisSaturday) else {
            fatalError("Could not get a valid date!!! (This should never happen...)")
        }
        return dateFormatter.string(from: d)
    }
    
}