我正在尝试弄清楚如何确定给定时间戳今天是否发生,或+1 / -1天。基本上,我想做这样的事情(Pseudocode)
IF days_from_today(timestamp) == -1 RETURN 'Yesterday'
ELSE IF days_from_today(timestamp) == 0 RETURN 'Today'
ELSE IF days_from_today(timestamp) == 1 RETURN 'Tomorrow'
ELSE IF days_from_today(timestamp) < 1 RETURN days_from_today(timestamp) + ' days ago'
ELSE RETURN 'In ' + days_from_today(timestamp) + ' ago'
至关重要的是,它需要在Swift中,我正在努力使用NSDate / NSCalendar对象。我开始研究这样的时差:
let calendar = NSCalendar.currentCalendar()
let date = NSDate(timeIntervalSince1970: Double(timestamp))
let timeDifference = calendar.components([.Second,.Minute,.Day,.Hour],
fromDate: date, toDate: NSDate(), options: NSCalendarOptions())
然而,以这种方式进行比较并不容易,因为.Day
根据一天中的时间和时间戳而不同。在PHP中,我只是使用mktime来创建一个基于当天开始的新日期(即mktime(0,0,0)
),但我不确定在Swift中最简单的方法。
有没有人对如何处理这个问题有个好主意?也许NSDate或类似的东西的扩展最好?
Calendar
有这三种情况的方法
func isDateInYesterday(_ date: Date) -> Bool
func isDateInToday(_ date: Date) -> Bool
func isDateInTomorrow(_ date: Date) -> Bool
要计算比昨天更早的天数使用
func dateComponents(_ components: Set<Calendar.Component>,
from start: Date,
to end: Date) -> DateComponents
将[.day]
传递给components
并从结果中获取day
属性。
这个函数通过剥离时间部分(Swift 3+)来考虑is in
的早期和晚期日期。
func dayDifference(from interval : TimeInterval) -> String
{
let calendar = Calendar.current
let date = Date(timeIntervalSince1970: interval)
if calendar.isDateInYesterday(date) { return "Yesterday" }
else if calendar.isDateInToday(date) { return "Today" }
else if calendar.isDateInTomorrow(date) { return "Tomorrow" }
else {
let startOfNow = calendar.startOfDay(for: Date())
let startOfTimeStamp = calendar.startOfDay(for: date)
let components = calendar.dateComponents([.day], from: startOfNow, to: startOfTimeStamp)
let day = components.day!
if day < 1 { return "\(-day) days ago" }
else { return "In \(day) days" }
}
}
或者,您可以使用DateFormatter
进行昨天,今天和明天免费获取本地化字符串
func dayDifference(from interval : TimeInterval) -> String
{
let calendar = Calendar.current
let date = Date(timeIntervalSince1970: interval)
let startOfNow = calendar.startOfDay(for: Date())
let startOfTimeStamp = calendar.startOfDay(for: date)
let components = calendar.dateComponents([.day], from: startOfNow, to: startOfTimeStamp)
let day = components.day!
if abs(day) < 2 {
let formatter = DateFormatter()
formatter.dateStyle = .short
formatter.timeStyle = .none
formatter.doesRelativeDateFormatting = true
return formatter.string(from: date)
} else if day > 1 {
return "In \(day) days"
} else {
return "\(-day) days ago"
}
}
Swift 3/4/5:
Calendar.current.isDateInToday(yourDate)
Calendar.current.isDateInYesterday(yourDate)
Calendar.current.isDateInTomorrow(yourDate)
另外:
Calendar.current.isDateInWeekend(yourDate)
请注意,对于某些国家/地区周末可能与周六至周日不同,这取决于日历。
您也可以使用autoupdatingCurrent
而不是current
日历来跟踪用户更新。你以同样的方式使用它:
Calendar.autoupdatingCurrent.isDateInToday(yourDate)
Calendar
是NSCalendar
的类型别名。
Swift 4更新:
let calendar = Calendar.current
let date = Date()
calendar.isDateInYesterday(date)
calendar.isDateInToday(date)
calendar.isDateInTomorrow(date)
NSCalendar具有可以直接使用的新方法。
NSCalendar.currentCalendar().isDateInTomorrow(NSDate())//Replace NSDate() with your date
NSCalendar.currentCalendar().isDateInYesterday()
NSCalendar.currentCalendar().isDateInTomorrow()
希望这可以帮助
在Swift 5和iOS 13上使用RelativeDateTimeFormatter,
let formatter = RelativeDateTimeFormatter()
formatter.dateTimeStyle = .named
formatter.localizedString(from: DateComponents(day: -1)) // "yesterday"
formatter.localizedString(from: DateComponents(day: 1)) // "Tomorrow"
formatter.localizedString(from: DateComponents(hour: 2)) // "in 2 hours"
formatter.localizedString(from: DateComponents(minute: 45)) // "in 45 minutes"
1)根据您的示例,您希望接收标签“昨天”,“今天”等。默认情况下,iOS可以执行此操作:
2)如果你想在iOS不自己添加这些标签时计算自定义标签,那么你也可以使用DateFormatter
和doesRelativeDateFormatting == true
的2个doesRelativeDateFormatting == false
对象,并比较它们的结果日期字符串是相同还是不同