ios - 如何在 Swift 中使用带有日期而不是数字的范围 slider ？

Question

我正在查看范围 slider 的实现:https://github.com/warchimede/RangeSlider我看到它的 lowerValue 和 upperValue 默认设置为 0.2 和 0.8:

@IBInspectable var lowerValue: Double = 0.2 {
    didSet {
        if lowerValue < minimumValue {
            lowerValue = minimumValue
        }
        updateLayerFrames()
    }
}

@IBInspectable var upperValue: Double = 0.8 {
    didSet {
        if upperValue > maximumValue {
            upperValue = maximumValue
        }
        updateLayerFrames()
    }
}

它还有 minimumValue 和 maximumValue 设置为 0 和 1:

@IBInspectable var minimumValue: Double = 0.0 {
    willSet(newValue) {
        assert(newValue < maximumValue, "RangeSlider: minimumValue should be lower than maximumValue")
    }
    didSet {
        updateLayerFrames()
    }
}

@IBInspectable var maximumValue: Double = 1.0 {
    willSet(newValue) {
        assert(newValue > minimumValue, "RangeSlider: maximumValue should be greater than minimumValue")
    }
    didSet {
        updateLayerFrames()
    }
}

我想更改此 slider 的行为，使其成为范围日期选择器 - maximumValue 应为当前日期，minimumValue 应为过去某个日期，例如6个月前。你能帮我解决这个问题，并给出一些提示是否可以使用这个范围 slider 来做到这一点？

Answer 1

应该这样做。

class ViewController: UIViewController {

    var slider:UISlider?
    // These number values represent each slider position
    let daysInPast = [14, 13, 12, 11, 10, 9, 8, 7, 6, 5, 4, 3, 2, 1, 0] //Add your values here - this sets from two past weeks to current day
    let secondsPerDay = 86400
    var oldIndex = 0

    override func viewDidLoad() {
        super.viewDidLoad()
        slider = UISlider(frame: self.view.bounds)
        self.view.addSubview(slider!)

        // slider values go from 0 to the number of values in your numbers array
        var numberOfSteps = Float(numbers.count - 1)
        slider!.maximumValue = numberOfSteps;
        slider!.minimumValue = 0;

        // As the slider moves it will continously call the -valueChanged:
        slider!.continuous = true; // false makes it call only once you let go
        slider!.addTarget(self, action: "valueChanged:", forControlEvents: .ValueChanged)
    }

    func valueChanged(sender: UISlider) {
        // round the slider position to the nearest index of the numbers array
        var index = (Int)(slider!.value + 0.5);
        slider?.setValue(Float(index), animated: false)
        var dayInPast = daysInPast[index]; // <-- This numeric value you want

        if oldIndex != index {

            let today = NSDate() //today
            //every day value in the slider will be multiplied by number of seconds in day
            let pickedDate = today.dateByAddingTimeInterval(-secondsPerDay * dayInPast)
            let calendar = NSCalendar.currentCalendar()
            let components = calendar.components([.Month, .Year, .Day], fromDate: pickedDate)
            let month = components.month
            let year = components.year
            let day = components.day

            print("Date picked with slider is \(month)/\(day), \(year)")

            oldIndex = index
        }
    }
}