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
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……
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)
你也可以使用NSDateFormatter的方便方法，例如:
func printTimestamp() {
let timestamp = NSDateFormatter.localizedStringFromDate(NSDate(), dateStyle: .MediumStyle, timeStyle: .ShortStyle)
print(timestamp)
}
printTimestamp() // Prints "Sep 9, 2014, 4:30 AM"
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……
一行Swift 5.2
let date = String(DateFormatter.localizedString(from: Date(), dateStyle: .medium, timeStyle: .short))
如果你需要以一种特定的方式格式化答案，你可以很容易地使用这个方法，default = "dd-MM-yyyy"。
extension Date {
func today(format : String = "dd-MM-yyyy") -> String{
let date = Date()
let formatter = DateFormatter()
formatter.dateFormat = format
return formatter.string(from: date)
}
}
获取今天的日期现在可以使用
Date().today() or Date().today("dd/MM/yyyy")
