从操场开始。我正在尝试创建一个简单的应用程序。
我创建了一个date对象,就像这样:
var date = NSDate()
我怎样才能得到当前的时间?在其他语言中,我可以这样做:
var hour = date.hour
但我找不到任何这样的属性/方法。我找到了一个方法,dateWithCalendarFormat。我应该用这个吗?如果是,怎么做?
从操场开始。我正在尝试创建一个简单的应用程序。
我创建了一个date对象,就像这样:
var date = NSDate()
我怎样才能得到当前的时间?在其他语言中,我可以这样做:
var hour = date.hour
但我找不到任何这样的属性/方法。我找到了一个方法,dateWithCalendarFormat。我应该用这个吗?如果是,怎么做?
当前回答
你可以从Dateformatter获取
let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "dd/MM/yyyy"
let dateString = dateFormatter.string(from:Date())
print(dateString)
其他回答
扩展noiiv的史诗般的简洁解决方案,这里是更简洁的Swift 3/4实现:
斯威夫特3/4
let components = Calendar.current.dateComponents([.hour, .minute], from: Date())
let (hour, minute) = (components.hour, components.minute)
同时,扩展Leo Dabus的扩展,我们可以有:
extension Date {
func components(_ components: Set<Calendar.Component>) -> DateComponents {
return Calendar.current.dateComponents(components, from: self)
}
func component(_ component: Calendar.Component) -> Int {
return Calendar.current.component(component, from: self)
}
var era: Int { return component(.era) }
var year: Int { return component(.year) }
var month: Int { return component(.month) }
var day: Int { return component(.day) }
var hour: Int { return component(.hour) }
var minute: Int { return component(.minute) }
var second: Int { return component(.second) }
var weekday: Int { return component(.weekday) }
var weekdayOrdinal: Int { return component(.weekdayOrdinal) }
var quarter: Int { return component(.quarter) }
var weekOfMonth: Int { return component(.weekOfMonth) }
var weekOfYear: Int { return component(.weekOfYear) }
var yearForWeekOfYear: Int { return component(.yearForWeekOfYear) }
var nanosecond: Int { return component(.nanosecond) }
var calendar: Calendar? { return components([.calendar]).calendar }
var timeZone: TimeZone? { return components([.timeZone]).timeZone }
}
像这样使用它:
let date = Date()
let (hour, minute) = (date.hour, date.minute)
Swift 3更新:
let date = Date()
let calendar = Calendar.current
let hour = calendar.component(.hour, from: date)
let minutes = calendar.component(.minute, from: date)
我是这样做的:
let date = NSDate()
let calendar = NSCalendar.currentCalendar()
let components = calendar.components(.CalendarUnitHour | .CalendarUnitMinute, fromDate: date)
let hour = components.hour
let minutes = components.minute
在objective-c中看到同样的问题,我如何从NSDate中获得小时和分钟?
和Nate的答案相比,你得到的是数字,而不是字符串……
使用Swift 5 (Xcode 10 & Xcode 11)(来自法国UTC)
func getCurrentDateTime() {
let now = Date()
let formatter = DateFormatter()
formatter.locale = Locale(identifier: "fr_FR")
formatter.dateFormat = "EEEE dd MMMM YYYY HH:mm"
myLabel.text = formatter.string(from: now)
myLabel.font = UIFont(name: "HelveticaNeue-Light", size: 12)
myLabel.textColor = UIColor.black
}
如果您只想显示日期,请设置formatter.dateFormat
formatter.dateFormat = "EEEE dd MMMM YYYY"
若要只显示小时,请更改格式化程序。dateFormat来
formatter.dateFormat = "HH:mm"
不要忘记在viewDidLoad上添加getCurrentDateTime()。
你可以用swift 4或5像bellow
let date = Date()
let df = DateFormatter()
df.dateFormat = "yyyy-MM-dd HH:mm:ss"
let dateString = df.string(from: date)
输出将像波纹管
2019-12-20 09:40:08
使用Date Formatter -Swift 3.0
//Date
let dateFormatter = DateFormatter()
dateFormatter.dateStyle = .medium
let dateString = "Current date is: \(dateFormatter.string(from: Date() as Date))"
labelfordate.text = String(dateString)
//Time
let timeFormatter = DateFormatter()
timeFormatter.timeStyle = .medium
let timeString = "Current time is: \(timeFormatter.string(from: Date() as Date))"
labelfortime.text = String(timeString)
每秒钟更新一次日期和时间
override func viewDidLoad() {
super.viewDidLoad()
timer = Timer.scheduledTimer(timeInterval: 1, target: self, selector: #selector(DateAndTime.action), userInfo: nil, repeats: true)
}
func action()
{
//Date
let dateFormatter = DateFormatter()
dateFormatter.dateStyle = .medium
let dateString = "Current date is: \(dateFormatter.string(from: Date() as Date))"
labelfordate.text = String(dateString)
//Time
let timeFormatter = DateFormatter()
timeFormatter.timeStyle = .medium
let timeString = "Current time is: \(timeFormatter.string(from: Date() as Date))"
labelfortime.text = String(timeString)
}
注意:定时器代码中的DateAndTime是类名。