Question

我使用的是openweathermap.org api。我正在获得日出和日落日期并比较这些。 date1是日出，date2是日落日期。我检查天气是否真实，答案是肯定的。但答案是错误的。我比较月，日和时间。我的代码有什么问题？

这是我的代码：

func checkDate(date1:NSDate, date2:NSDate){
    // Date comparision to compare current date and end date.
    var dateComparisionResult:NSComparisonResult = NSDate().compare(date1)
    var dateComparision:NSComparisonResult = NSDate().compare(date2)

    if dateComparisionResult == NSComparisonResult.OrderedDescending || dateComparisionResult == NSComparisonResult.OrderedSame && dateComparision == NSComparisonResult.OrderedAscending
    {
        //result is
        answerLabel.text = "yes".uppercaseString
        self.view.backgroundColor = UIColor.whiteColor()
        answerLabel.textColor = UIColor.blackColor()
    }else{
        answerLabel.text = "no".uppercaseString
        self.view.backgroundColor = UIColor.blackColor()
        answerLabel.textColor = UIColor.whiteColor()
    }

}

Answer 1

根据评论，您似乎只是在检查当前时间是否在白天。

所以，首先，不要只是简单地只检查现在，而是让它成为NSDate()扩展名，可以随时应用。

extension NSDate {
    func between(firstDate: NSDate, _ secondDate: NSDate) -> Bool {
        // TODO: determine if self is between first and second date            
    }
}

为了使这更容易阅读，让我们为NSDate提出一些方便的重载运算符，对吗？

func == (left: NSDate, right: NSDate) {
    return left.compare(right) == .OrderedSame
}

func > (left: NSDate, right: NSDate) {
    return left.compare(right) == .OrderedDescending
}

func < (left: NSDate, right: NSDate) {
     return left.compare(right) == .OrderedAscending
} 

func != (left: NSDate, right: NSDate) {
    return !(left == right)
}

func >= (left: NSDate, right: NSDate) {
    return (left == right) || (left > right)
}

func <= (left: NSDate, right: NSDate) {
    return (left == right) || (left < right)
}

现在我们已准备好回到我们提出的between方法，现在变得非常简单：

extension NSDate: Equatable, Comparable {
    func between(firstDate: NSDate, _ secondDate: NSDate) -> Bool {
        return self >= firstDate && self <= secondDate
    }
}

我们是否想要“或等于”比较符合我们的具体要求。但是添加运算符使得它更加清晰，并为我们在其他场景中使用添加了方便的运算符，而且编写单元测试要好得多。作为额外的奖励，我们现在可以将NSDate声明为conforming to Equatable and Comparable。

现在，确定白天的特定时间是否如此简单：

let isDaylight = NSDate().between(sunrise, sunset)

或者也许：

if NSDate().between(sunrise, sunset) {
    // daylight
} else {
    // not daylight
}

Answer 2

我编辑了这样的代码并且有效！

代码：

func checkDate(date1:NSDate, date2:NSDate){
        // Date comparision to compare current date and end date.
        var dateComparisionResult:NSComparisonResult = NSDate().compare(date1)
        var dateComparision:NSComparisonResult = NSDate().compare(date2)

        if dateComparisionResult == NSComparisonResult.OrderedSame || dateComparisionResult == NSComparisonResult.OrderedDescending && dateComparision == NSComparisonResult.OrderedAscending
        {
            //if It is daylight outside
            answerLabel.text = "yes".uppercaseString
            self.view.backgroundColor = UIColor.whiteColor()
            answerLabel.textColor = UIColor.blackColor()
        }else{
             //if It's not daylight outside
            answerLabel.text = "no".uppercaseString
            self.view.backgroundColor = UIColor.blackColor()
            answerLabel.textColor = UIColor.whiteColor()
        }

    }

Swift - openweathermap.org api：比较函数有什么问题？

2 个答案: