如何使用 NSDate 在 Swift 3 中获取时间（小时、分钟、秒）？答案

【问题标题】：How to get time (hour, minute, second) in Swift 3 using NSDate?如何使用 NSDate 在 Swift 3 中获取时间（小时、分钟、秒）？
【发布时间】：2016-11-09 23:26:47
【问题描述】：

你如何确定 Swift 3 中 NSDate 类的小时、分钟和秒？

在 Swift 2 中：

let date = NSDate()
let calendar = NSCalendar.currentCalendar()
let components = calendar.components(.Hour, fromDate: date)
let hour = components.hour

斯威夫特 3？

【问题讨论】：

另见this answer。
How to get the current time as datetime的可能重复

标签： nsdate swift3

【解决方案1】：

在 Swift 3.0 中，Apple 移除了 'NS' 前缀，让一切变得简单。下面是从“日期”类（NSDate 替代）中获取小时、分钟和秒的方法

let date = Date()
let calendar = Calendar.current

let hour = calendar.component(.hour, from: date)
let minutes = calendar.component(.minute, from: date)
let seconds = calendar.component(.second, from: date)
print("hours = \(hour):\(minutes):\(seconds)")

像这些你可以通过相应的获取时代、年、月、日等。

【讨论】：

【解决方案2】：

Swift 4.2 和 5

// *** Create date ***
let date = Date()

// *** create calendar object ***
var calendar = Calendar.current

// *** Get components using current Local & Timezone ***
print(calendar.dateComponents([.year, .month, .day, .hour, .minute], from: date))

// *** define calendar components to use as well Timezone to UTC ***
calendar.timeZone = TimeZone(identifier: "UTC")!

// *** Get All components from date ***
let components = calendar.dateComponents([.hour, .year, .minute], from: date)
print("All Components : \(components)")

// *** Get Individual components from date ***
let hour = calendar.component(.hour, from: date)
let minutes = calendar.component(.minute, from: date)
let seconds = calendar.component(.second, from: date)
print("\(hour):\(minutes):\(seconds)")

Swift 3.0

// *** Create date ***
let date = Date()

// *** create calendar object ***
var calendar = NSCalendar.current

// *** Get components using current Local & Timezone ***    
print(calendar.dateComponents([.year, .month, .day, .hour, .minute], from: date as Date))

// *** define calendar components to use as well Timezone to UTC ***
let unitFlags = Set<Calendar.Component>([.hour, .year, .minute])
calendar.timeZone = TimeZone(identifier: "UTC")!

// *** Get All components from date ***
let components = calendar.dateComponents(unitFlags, from: date)
print("All Components : \(components)")

// *** Get Individual components from date ***
let hour = calendar.component(.hour, from: date)
let minutes = calendar.component(.minute, from: date)
let seconds = calendar.component(.second, from: date)
print("\(hour):\(minutes):\(seconds)")

【讨论】：

如果我在网上得到'Component' is not a member type of 'Calendar' `let unitFlags...``
您的问题我不清楚，您如何在Calendar.Component 中添加非会员类型？考虑您的日期在“02/12/15, 16:46”之后，其中秒数不可用，您尝试使用组件提取秒数，在这种情况下它将返回您0。
我发现了我的问题...我声明了一个名为 Calendar 的结构，它显然干扰了 Calendar.Component。

【解决方案3】：

let date = Date()       
let units: Set<Calendar.Component> = [.hour, .day, .month, .year]
let comps = Calendar.current.dateComponents(units, from: date)

【讨论】：

【解决方案4】：

斯威夫特 4

    let calendar = Calendar.current
    let time=calendar.dateComponents([.hour,.minute,.second], from: Date())
    print("\(time.hour!):\(time.minute!):\(time.second!)")

【讨论】：

【解决方案5】：

在 Swift 3 中你可以做到这一点，

let date = Date()
let hour = Calendar.current.component(.hour, from: date)

【讨论】：

绝对是最简洁最简单的答案）

【解决方案6】：

Swift 5+

extension Date {
    
    func get(_ type: Calendar.Component)-> String {
        let calendar = Calendar.current
        let t = calendar.component(type, from: self)
        return (t < 10 ? "0\(t)" : t.description)
    }
}

用法：

print(Date().get(.year)) // => 2020
print(Date().get(.month)) // => 08
print(Date().get(.day)) // => 18

【讨论】：

【解决方案7】：

let hours = time / 3600
let minutes = (time / 60) % 60
let seconds = time % 60
return String(format: "%0.2d:%0.2d:%0.2d", hours, minutes, seconds)

【讨论】：

【解决方案8】：

为了最有用，我创建了这个函数：

func dateFormatting() -> String {
    let date = Date()
    let dateFormatter = DateFormatter()
    dateFormatter.dateFormat = "EEEE dd MMMM yyyy - HH:mm:ss"//"EE" to get short style
    let mydt = dateFormatter.string(from: date).capitalized

    return "\(mydt)"
}

你只需像这样在任何你想要的地方调用它：

print("Date = \(self.dateFormatting())")

这是输出：

Date = Monday 15 October 2018 - 17:26:29

如果只想改变时间：

dateFormatter.dateFormat  = "HH:mm:ss"

这是输出：

Date = 17:27:30

就是这样……

【讨论】：

【解决方案9】：

swift 4

==> Getting iOS device current time:-

print(" ---> ",(Calendar.current.component(.hour, from: Date())),":",
               (Calendar.current.component(.minute, from: Date())),":",
               (Calendar.current.component(.second, from: Date())))

output: ---> 10 : 11: 34

【讨论】：

【解决方案10】：

这对于那些想在不止一堂课中使用当前日期的人来说可能很方便。

extension String {

    func  getCurrentTime() -> String {
    
        let date = Date()
        let calendar = Calendar.current
        
        let year = calendar.component(.year, from: date)
        let month = calendar.component(.month, from: date)
        let day = calendar.component(.day, from: date)
        let hour = calendar.component(.hour, from: date)
        let minutes = calendar.component(.minute, from: date)
        let seconds = calendar.component(.second, from: date)
    
        let realTime = "\(year)-\(month)-\(day)-\(hour)-\(minutes)-\(seconds)"
    
        return realTime
    }
}

用法

var time = ""
time = time.getCurrentTime()
print(time)   // 1900-12-09-12-59

【讨论】：

【解决方案11】：

Swift 5+ Date 扩展以获取任何所需日期组件的Int 值：

extension Date {
    func component(_ component: Calendar.Component) -> Int {
        Calendar.current.component(component, from: self)
    }
}

用法：

let now = Date()
print(now.component(.year))  // 2021
print(now.component(.month)) // 12
print(now.component(.day))   // 30

【讨论】：