ios - Swift - 如何获取当前时间(以秒为单位)？

Question

一个用户在不同的时区发表评论，另一个用户在不同的时区查看该评论。当转换回用户设备上的时区时，时间应该相同。

这是我正在尝试的，但收到“ fatal error :在展开可选值时意外发现 nil”。当我试图减去“时间”时，错误发生在我的距离时间变量中。我在它执行之前打印了时间，它说“nil”。请问有什么帮助吗？

import UIKit

类EventCommentCell:UITableViewCell {

var obj : EventCommentObj!

@IBOutlet var profileImage: UIImageView!
@IBOutlet var commentMessage: UITextView!
@IBOutlet var time: UILabel!
override func awakeFromNib() {
    super.awakeFromNib()
    // Initialization code
}

override func setSelected(selected: Bool, animated: Bool) {
    super.setSelected(selected, animated: animated)

    // Configure the view for the selected state
}

func setData(){



    profileImage.layer.borderWidth = 1
    profileImage.layer.masksToBounds = false


    profileImage.layer.borderColor = UIColor(red: 0.125, green: 0.757, blue: 0.569, alpha: 1.0).CGColor
    profileImage.layer.cornerRadius = profileImage.frame.height/2
    profileImage.clipsToBounds = true

    print("The Image URL : \(obj.profileImage)")


    ImageLoader.sharedLoader.imageForUrl(obj.profileImage, completionHandler:{(image: UIImage?, url: String) in
        self.profileImage.image  = image
    })

    let message = "\(obj.username) \n\(obj.comment)"



    let attributedString = NSMutableAttributedString(string: message as String)

    let range: NSRange = (message as NSString).rangeOfString(obj.username as String)
    let range1: NSRange = (message as NSString).rangeOfString(obj.comment as String)
    let font = UIFont.boldSystemFontOfSize(commentMessage.font!.pointSize)

    attributedString.addAttribute(NSFontAttributeName, value: font, range: range)
    attributedString.addAttribute(NSForegroundColorAttributeName, value: UIColor(red: 0.125, green: 0.757, blue: 0.569, alpha: 1.0), range: range)

    commentMessage.attributedText = attributedString

    time.text = getCreationTimeInt(obj.created_on)

}

func getCreationTimeInt(dateString : String) -> String{

    let dateFormatter = NSDateFormatter()
    dateFormatter.locale = NSLocale.currentLocale()
    dateFormatter.dateFormat = "yyyy-MM-dd HH:mm:ss"
    dateFormatter.timeZone = NSTimeZone(forSecondsFromGMT: 0)
    dateFormatter.timeZone = NSTimeZone.systemTimeZone()


    let time = dateFormatter.dateFromString(dateString)?.timeIntervalSince1970

    let distanceTime = NSDate().timeIntervalSince1970 - time!

    let stringTime = returnDistanceTime(distanceTime)

    print("**** The time \(stringTime)", terminator: "")

    return stringTime

}

func returnDistanceTime(distanceTime : Double) -> String{

    var stringTime = ""

    if (distanceTime < 0) {
        stringTime = "0s"


    }else{
        if(distanceTime < 60){
            stringTime = "\(Int(distanceTime))s"


        }else{
            if(distanceTime < 3600){

                stringTime = "\(Int(distanceTime/60))m"

            }else{

                if(distanceTime < 3600*24){
                    stringTime = "\(Int(distanceTime/3600))h"

                }else{

                    if(distanceTime < 3600*24*7) {

                        stringTime = "\(Int(distanceTime/3600/24))d"

                    }else{
                        stringTime = "\(Int(distanceTime/3600/24/7))w"

                    }
                }
            }
        }
    }
    return stringTime
}

}

Answer 1

欢迎来到堆栈溢出。我将你所拥有的插入到 Playground 中，效果非常好。这是我所拥有的:

//: Playground - noun: a place where people can play

import Cocoa


func returnDistanceTime(distanceTime: NSTimeInterval) -> String{

    let dateFormatter = NSDateFormatter()
    dateFormatter.dateFormat = "yyyy-MM-dd HH:mm:ss"
    return dateFormatter.stringFromDate(NSDate())
}



func getCreationTimeInt(dateString : String) -> String{

    let dateFormatter = NSDateFormatter()
    dateFormatter.locale = NSLocale.currentLocale()
    dateFormatter.dateFormat = "yyyy-MM-dd HH:mm:ss"
    dateFormatter.timeZone = NSTimeZone(forSecondsFromGMT: 0)
    dateFormatter.timeZone = NSTimeZone.systemTimeZone()
    dateFormatter.locale = NSLocale(localeIdentifier: "en_US_POSIX")

    let time = dateFormatter.dateFromString(dateString)?.timeIntervalSince1970

    let distanceTime = NSDate().timeIntervalSince1970 - time!

    let stringTime = returnDistanceTime(distanceTime)

    print("**** The time \(stringTime)", terminator: "")

    return stringTime

}



getCreationTimeInt("2016-03-01 12:12:12")