swift - 检查时间是否在范围内

Question

在应用程序中，我从核心数据中获取一个值(这个值是一个日期)并将它与一个时间(以字符串的格式)进行比较，并相应地执行操作。但是由于某种原因，if 语句似乎不起作用。无论是哪个时间，结果总是使用 value1(时间 0:00 到 5:30)进行除法(请查看下面的代码)。我已经检查过核心数据获取是否具有正确的名称，是的，它应该可以正常工作。有人有主意吗？

函数计算(){

        let appDelegate = UIApplication.sharedApplication().delegate as! AppDelegate
        let managedContext = appDelegate.managedObjectContext
        let fetchRequest = NSFetchRequest(entityName: "Settings")

        do {
            let results = try managedContext.executeFetchRequest(fetchRequest)
            Settings = results as! [NSManagedObject]

            for result in results as! [NSManagedObject] {

                correctionRatio = result.valueForKey("correctionRatio") as! Int
                target = result.valueForKey("targetbG") as! Int
                value1 = result.valueForKey("value1") as! Int
                value2 = result.valueForKey("value2") as! Int
                value3 = result.valueForKey("value3") as! Int
                value4 = result.valueForKey("value4") as! Int
                value5 = result.valueForKey("value5") as! Int

                if bGTextfield.text != "" && carbTextfield.text != "" {

                    current = Int(bGTextfield.text!)
                    carb = Int(carbTextfield.text!)

                    let currentTime = NSDate()
                    let timeFormatter = NSDateFormatter()
                    timeFormatter.locale = NSLocale.currentLocale()
                    timeFormatter.dateFormat = "HH:mm"
                    let time = timeFormatter.stringFromDate(currentTime)


                    if time > "00:00" && time < "5:30" {
                        food = carb / value1
                    } else if time > "5:31" && time < "11:00"{
                        food = carb / value2
                    } else if time > "11:01" && time < "17:00"{
                        food = carb / value3
                    } else if time > "17:01" && time < "21:30" {
                        food = carb / value4
                    } else if time > "21:31" && time < "23:59" {
                        food = carb / value5
                    }



                    if 4 ... 9 ~= Double(currentbG){

                        doseLabel.text = String(foodInsulin)


                    } else if 9.1 ... 100 ~= Double(currentbG) {

                        bgDiff = currentbG - targetbG
                        correction = bgDiff / correctionRatio
                        total = food + correctionInsulin

                        doseLabel.text = String(total)
                    }

    }

谢谢

Answer 1

我在 NSDate 扩展中做了类似的事情:

private class func timeAsIntegerFromDate(date: NSDate) -> Int {
    let currentCal = NSCalendar.currentCalendar()
    currentCal.timeZone = NSTimeZone.localTimeZone()
    let comps: NSDateComponents = currentCal.components([NSCalendarUnit.Hour, NSCalendarUnit.Minute], fromDate: date)
    return comps.hour * 100 + comps.minute
}

private class func timeIsBetween(startDate: NSDate, endDate: NSDate) -> Bool {
    let startTime = NSDate.timeAsIntegerFromDate(startDate)
    let endTime = NSDate.timeAsIntegerFromDate(endDate)
    let nowTime = NSDate.timeAsIntegerFromDate(NSDate())

    if startTime == endTime { return false }

    if startTime < endTime {
        if nowTime >= startTime {
            if nowTime < endTime { return true }
        }
        return false
    } else {
        if nowTime >= startTime || nowTime < endTime {
            return true
        }
        return false
    }
}

我相信它可以稍微清理一下，并进一步改进。我所做的是将 NSDate 转换为 Int 然后检查哪个更大更小。基本原理是将时间乘以 100 并将分钟添加到它的末尾并进行比较。