如何使用NSDate在Swift 3中获取时间（小时，分钟，秒）？

Question

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？

Answer 1

在Swift 3.0中，Apple删除了“NS”前缀并使一切变得简单。以下是从'Date'类获取小时，分钟和秒的方法（NSDate alternate）

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方式获得时代，年，月，日期等。

Answer 2

Swift 4.2＆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)")

Answer 3

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

Answer 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!)")

Answer 5

在Swift 3中你可以这样做，

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

Answer 6

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)

Answer 7

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

Answer 8

为了最好用，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

如果只想时间改变：

dateFormatter.dateFormat  = "HH:mm:ss"

这是输出：

Date = 17:27:30

就是这样......