如何获取当月的开始日期和结束日期(Swift 3)

Question

我正在尝试以dd/MM/yyyy格式获取当月的开始和结束日期.我尝试使用扩展作为SO问题中的回答.但似乎这不是我想要的(格式不同,而且它给了我上个月的最后一个日期和当前月份,但是一个日期).有人能帮我吗.

扩展类:

extension Date {
    func startOfMonth() -> Date? {
        let comp: DateComponents = Calendar.current.dateComponents([.year, .month, .hour], from: Calendar.current.startOfDay(for: self))
        return Calendar.current.date(from: comp)!
    }

    func endOfMonth() -> Date? {
        var comp: DateComponents = Calendar.current.dateComponents([.month, .day, .hour], from: Calendar.current.startOfDay(for: self))
        comp.month = 1
        comp.day = -1
        return Calendar.current.date(byAdding: comp, to: self.startOfMonth()!)
    }
}

我的结构:

struct Constants{

    // keys required for making a Login call (POST Method)
    struct LoginKeys {
       .....
    }

    struct RankingKeys {

        static let DateFrom = String(describing: Date().startOfMonth()) //giving me 2016-11-30 16:00:00 +0000 
        static let DateTo  = String(describing: Date().endOfMonth())
//2016-12-30 16:00:00 +0000
    }
}

预期结果:

DateFrom  = "01/12/2016"
DateTo = "31/12/2016"

Answer 1

你应该写这个简单的代码:

let dateFormatter = DateFormatter()
let date = Date()
dateFormatter.dateFormat = "dd-MM-yyyy"

开始日期:

let comp: DateComponents = Calendar.current.dateComponents([.year, .month], from: date)
let startOfMonth = Calendar.current.date(from: comp)!
print(dateFormatter.string(from: startOfMonth))

截止日期:

var comps2 = DateComponents()
comps2.month = 1
comps2.day = -1
let endOfMonth = Calendar.current.date(byAdding: comps2, to: startOfMonth)
print(dateFormatter.string(from: endOfMonth!)) 

Answer 2

这是为 Date 创建扩展的简单解决方案，如下所示：

extension Date {

func startOfMonth() -> Date {
    let interval = Calendar.current.dateInterval(of: .month, for: self)
    return (interval?.start.toLocalTime())! // Without toLocalTime it give last months last date
}

func endOfMonth() -> Date {
    let interval = Calendar.current.dateInterval(of: .month, for: self)
    return interval!.end
}

// Convert UTC (or GMT) to local time
func toLocalTime() -> Date {
    let timezone    = TimeZone.current
    let seconds     = TimeInterval(timezone.secondsFromGMT(for: self))
    return Date(timeInterval: seconds, since: self)
}}

然后像这样调用你的 Date 实例

print(Date().startOfMonth())
print(Date().endOfMonth())

Answer 3

这就是我正在使用的.很简单,但它的工作原理.

extension Calendar {

func dayOfWeek(_ date: Date) -> Int {
    var dayOfWeek = self.component(.weekday, from: date) + 1 - self.firstWeekday

    if dayOfWeek <= 0 {
        dayOfWeek += 7
    }

    return dayOfWeek
}

func startOfWeek(_ date: Date) -> Date {
    return self.date(byAdding: DateComponents(day: -self.dayOfWeek(date) + 1), to: date)!
}

func endOfWeek(_ date: Date) -> Date {
    return self.date(byAdding: DateComponents(day: 6), to: self.startOfWeek(date))!
}

func startOfMonth(_ date: Date) -> Date {
    return self.date(from: self.dateComponents([.year, .month], from: date))!
}

func endOfMonth(_ date: Date) -> Date {
    return self.date(byAdding: DateComponents(month: 1, day: -1), to: self.startOfMonth(date))!
}

func startOfQuarter(_ date: Date) -> Date {
    let quarter = (self.component(.month, from: date) - 1) / 3 + 1
    return self.date(from: DateComponents(year: self.component(.year, from: date), month: (quarter - 1) * 3 + 1))!
}

func endOfQuarter(_ date: Date) -> Date {
    return self.date(byAdding: DateComponents(month: 3, day: -1), to: self.startOfQuarter(date))!
}

func startOfYear(_ date: Date) -> Date {
    return self.date(from: self.dateComponents([.year], from: date))!
}

func endOfYear(_ date: Date) -> Date {
    return self.date(from: DateComponents(year: self.component(.year, from: date), month: 12, day: 31))!
}
}