基于变量的调用方法(SWIFT)

Question

我有许多不同的 Coregraphics 函数可以绘制出表盘的不同元素。我希望放在一起的逻辑根据从当前小时提取的变量确定显示表盘的哪个方面。所有绘制方法都列在单独的 swift class/file 中。与其创建这个 if 语句塔，不如如何简化这个过程以将变量注入到调用的方法中？在此您可以看到 drawCanvas04() 与 4:00pm（或 16 小时）相关联。

    class ViewController: UIViewController {

    func updateTime() {

    var date:NSDate = NSDate()
    var calendar:NSCalendar = NSCalendar.currentCalendar()
    var components:NSDateComponents = calendar.components(NSCalendarUnit.CalendarUnitHour | NSCalendarUnit.CalendarUnitMinute | NSCalendarUnit.CalendarUnitSecond, fromDate: date)
    var hour = components.hour
    var minute = components.minute
    var seconds = components.second

    var time = "\(hour) : \(minute) : \(seconds)"
    println("\(time)")


    if hour == 16 || hour == 04 {

        ClockStyleKit.drawCanvas04()

    } else {

        if hour == 17 || hour == 05 {

        ClockStyleKit.drawCanvas05()

    } else {

        if hour == 18 || hour == 06 {

        ClockStyleKit.drawCanvas06()

    } else {

        if hour == 19 || hour == 07 {

        ClockStyleKit.drawCanvas07()

    } else {

        if hour == 20 || hour == 08 {

        ClockStyleKit.drawCanvas08()

    } else {

        if hour == 21 || hour == 09 {

        ClockStyleKit.drawCanvas09()

    } else {

        if hour == 22 || hour == 10 {

        ClockStyleKit.drawCanvas10()

    }

    if hour == 23 || hour == 11 {

        ClockStyleKit.drawCanvas11()

    }

    if hour == 24 || hour = 12 {

        ClockStyleKit.drawCanvas12()

    }

}

下面是调用样式包绘制方法的示例：

public class func drawCanvas07() {
    //// Color Declarations
    let color0 = UIColor(red: 0.894, green: 0.000, blue: 0.476, alpha: 1.000)

    //// HOUR7 Drawing
    var hOUR7Path = UIBezierPath(ovalInRect: CGRectMake(65.5, 155.99, 24, 24))
    color0.setFill()
    hOUR7Path.fill()

}

Answer 1

使用参数。同时减少 class 方法，使用实例方法代替 self.drawCanvas().

像这样：

func drawCanvas(canvas:Int) {
    switch canvas {
        case 0:
        // do something here for 0 o clock
        case 1:
        // 1 o clock
        // etc,
        default:
        // in case somehow you run out of bounds
    }
}

并使用 drawCanvas(10).

调用它