我从函数中获得秒值。例如,我得到:22分356秒。现在我想要减去这个值从现在并得到NSDate
,我怎么才能实现它?
还有,我有一个函数:
let date = NSDate(timeIntervalSinceNow:time.doubleValue)
let dateFormatter = NSDateFormatter()
dateFormatter.dateFormat = "dd.MM.yyyy"
self.lastSeenText = "last seen on (dateFormatter.stringFromDate(date))"
但是这个函数将的差异添加到上,现在。例如,如果差2天,而今天是12.10.15,它将打印14.10.15。
如何得到相反的值10.10.15?
在time.doubleValue
前使用减号;
let date = NSDate(timeIntervalSinceNow:-time.doubleValue)
let dateFormatter = NSDateFormatter()
dateFormatter.dateFormat = "dd.MM.yyyy"
self.lastSeenText = "last seen on (dateFormatter.stringFromDate(date))"
应该能行
let datenow = NSDate()
let twoDays: NSTimeInterval = 2*24*60*60
let date = datenow.dateByAddingTimeInterval(-twoDays)
let dateFormatter = NSDateFormatter()
dateFormatter.dateFormat = "dd.MM.yyyy"
let lastSeenText = "last seen on (dateFormatter.stringFromDate(date))"
改变这一行:
let date = NSDate(timeIntervalSinceNow:time.doubleValue)
:
let date = NSDate(timeIntervalSinceNow: -NSTimeInterval(time.doubleValue))
检查以下…
let datenow = NSDate()
let twoDays: NSTimeInterval = 2*24*60*60
let date = datenow.dateByAddingTimeInterval(-twoDays)
print(date)
let dateFormatter = NSDateFormatter()
dateFormatter.dateFormat = "dd.MM.yyyy"
let lastSeenText = "last seen on (dateFormatter.stringFromDate(date))"
print(lastSeenText)