Get current NSDate in timestamp format

问题:

I have a basic method which gets the current time and sets it in a string. However, how can I get it to format the current date & time in a UNIX since-1970 timestamp format?

Here is my code:

NSDate *currentTime = [NSDate date];
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:@"hh-mm"];
NSString *resultString = [dateFormatter stringFromDate: currentTime];

Is it possible to use NSDateFormatter to change the 'resultString' into a timestamp?

回答1:

Here's what I use:

NSString * timestamp = [NSString stringWithFormat:@"%f",[[NSDate date] timeIntervalSince1970] * 1000];

(times 1000 for milliseconds, otherwise, take that out)

If You're using it all the time, it might be nice to declare a macro

#define TimeStamp [NSString stringWithFormat:@"%f",[[NSDate date] timeIntervalSince1970] * 1000]

Then Call it like this:

NSString * timestamp = TimeStamp;

Or as a method:

- (NSString *) timeStamp {
    return [NSString stringWithFormat:@"%f",[[NSDate date] timeIntervalSince1970] * 1000];
}

As TimeInterval

- (NSTimeInterval) timeStamp {
    return [[NSDate date] timeIntervalSince1970] * 1000;
}

NOTE:

The 1000 is to convert the timestamp to milliseconds. You can remove this if you prefer your timeInterval in seconds.

Swift

If you'd like a global variable in Swift, you could use this:

var Timestamp: String {
    return "\(NSDate().timeIntervalSince1970 * 1000)"
}

Then, you can call it

println("Timestamp: \(Timestamp)")

Again, the *1000 is for miliseconds, if you'd prefer, you can remove that. If you want to keep it as an NSTimeInterval

var Timestamp: NSTimeInterval {
    return NSDate().timeIntervalSince1970 * 1000
}

Declare these outside of the context of any class and they'll be accessible anywhere.

回答2:

use [[NSDate date] timeIntervalSince1970]

回答3:

- (void)GetCurrentTimeStamp
    {
        NSDateFormatter *objDateformat = [[NSDateFormatter alloc] init];
        [objDateformat setDateFormat:@"yyyy-MM-dd"];
        NSString    *strTime = [objDateformat stringFromDate:[NSDate date]];
        NSString    *strUTCTime = [self GetUTCDateTimeFromLocalTime:strTime];//You can pass your date but be carefull about your date format of NSDateFormatter.
        NSDate *objUTCDate  = [objDateformat dateFromString:strUTCTime];
        long long milliseconds = (long long)([objUTCDate timeIntervalSince1970] * 1000.0);

        NSString *strTimeStamp = [NSString stringWithFormat:@"%lld",milliseconds];
NSLog(@"The Timestamp is = %@",strTimeStamp);
    }

 - (NSString *) GetUTCDateTimeFromLocalTime:(NSString *)IN_strLocalTime
    {
        NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
        [dateFormatter setDateFormat:@"yyyy-MM-dd"];
        NSDate  *objDate    = [dateFormatter dateFromString:IN_strLocalTime];
        [dateFormatter setTimeZone:[NSTimeZone timeZoneWithAbbreviation:@"UTC"]];
        NSString *strDateTime   = [dateFormatter stringFromDate:objDate];
        return strDateTime;
    }

NOTE :- The Timestamp must be in UTC Zone, So I convert our local Time to UTC Time.

回答4:

If you'd like to call this method directly on an NSDate object and get the timestamp as a string in milliseconds without any decimal places, define this method as a category:

@implementation NSDate (MyExtensions)
- (NSString *)unixTimestampInMilliseconds
{
     return [NSString stringWithFormat:@"%.0f", [self timeIntervalSince1970] * 1000];
}

回答5:

// The following method would return you timestamp after converting to milliseconds. [RETURNS STRING]

- (NSString *) timeInMiliSeconds
{
    NSDate *date = [NSDate date];
    NSString * timeInMS = [NSString stringWithFormat:@"%lld", [@(floor([date timeIntervalSince1970] * 1000)) longLongValue]];
    return timeInMS;
}

回答6:

Can also use

@(time(nil)).stringValue);

for timestamp in seconds.

回答7:

It's convenient to define a macro for get current timestamp

class Constant {
    struct Time {
        let now = { round(NSDate().timeIntervalSince1970) } // seconds
    }
} 

Then you can use let timestamp = Constant.Time.now()

回答8:

Swift:

I have a UILabel which shows TimeStamp over a Camera Preview.

    var timeStampTimer : NSTimer?
    var dateEnabled:  Bool?
    var timeEnabled: Bool?
   @IBOutlet weak var timeStampLabel: UILabel!

override func viewDidLoad() {
        super.viewDidLoad()
//Setting Initial Values to be false.
        dateEnabled =  false
        timeEnabled =  false
}

override func viewWillAppear(animated: Bool) {

        //Current Date and Time on Preview View
        timeStampLabel.text = timeStamp
        self.timeStampTimer = NSTimer.scheduledTimerWithTimeInterval(1.0,target: self, selector: Selector("updateCurrentDateAndTimeOnTimeStamperLabel"),userInfo: nil,repeats: true)
}

func updateCurrentDateAndTimeOnTimeStamperLabel()
    {
//Every Second, it updates time.

        switch (dateEnabled, timeEnabled) {
        case (true?, true?):
            timeStampLabel.text =  NSDateFormatter.localizedStringFromDate(NSDate(), dateStyle: .LongStyle, timeStyle: .MediumStyle)
            break;
        case (true?, false?):
            timeStampLabel.text = NSDateFormatter.localizedStringFromDate(NSDate(), dateStyle: .LongStyle, timeStyle: .NoStyle)
            break;

        case (false?, true?):
            timeStampLabel.text = NSDateFormatter.localizedStringFromDate(NSDate(), dateStyle: .NoStyle, timeStyle: .MediumStyle)
            break;
        case (false?, false?):
            timeStampLabel.text =  NSDateFormatter.localizedStringFromDate(NSDate(), dateStyle: .NoStyle, timeStyle: .NoStyle)
            break;
        default:
            break;

        }
    }

I am setting up a setting Button to trigger a alertView.

@IBAction func settingsButton(sender : AnyObject) {


let cameraSettingsAlert = UIAlertController(title: NSLocalizedString("Please choose a course", comment: ""), message: NSLocalizedString("", comment: ""), preferredStyle: .ActionSheet)

let timeStampOnAction = UIAlertAction(title: NSLocalizedString("Time Stamp on Photo", comment: ""), style: .Default) { action in

    self.dateEnabled = true
    self.timeEnabled =  true

}
let timeStampOffAction = UIAlertAction(title: NSLocalizedString("TimeStamp Off", comment: ""), style: .Default) { action in

    self.dateEnabled = false
    self.timeEnabled =  false

}
let dateOnlyAction = UIAlertAction(title: NSLocalizedString("Date Only", comment: ""), style: .Default) { action in

    self.dateEnabled = true
    self.timeEnabled =  false


}
let timeOnlyAction = UIAlertAction(title: NSLocalizedString("Time Only", comment: ""), style: .Default) { action in

    self.dateEnabled = false
    self.timeEnabled =  true
}

let cancel = UIAlertAction(title: NSLocalizedString("Cancel", comment: ""), style: .Cancel) { action in

}
cameraSettingsAlert.addAction(cancel)
cameraSettingsAlert.addAction(timeStampOnAction)
cameraSettingsAlert.addAction(timeStampOffAction)
cameraSettingsAlert.addAction(dateOnlyAction)
cameraSettingsAlert.addAction(timeOnlyAction)

self.presentViewController(cameraSettingsAlert, animated: true, completion: nil)

}

回答9:

    NSDate *todaysDate = [NSDate new];
NSDateFormatter *formatter = [NSDateFormatter new];
[formatter setDateFormat:@"MM-dd-yyyy HH:mm:ss"];
NSString *strDateTime = [formatter stringFromDate:todaysDate];

NSString *strFileName = [NSString stringWithFormat:@"/Users/Shared/Recording_%@.mov",strDateTime];
NSLog(@"filename:%@",strFileName);

Log will be : filename:/Users/Shared/Recording_06-28-2016 12:53:26.mov

回答10:

If you need time stamp as a string.

time_t result = time(NULL);                
NSString *timeStampString = [@(result) stringValue];

回答11:

To get timestamp from NSDate Swift 3

func getCurrentTimeStampWOMiliseconds(dateToConvert: NSDate) -> String {
    let objDateformat: DateFormatter = DateFormatter()
    objDateformat.dateFormat = "yyyy-MM-dd HH:mm:ss"
    let strTime: String = objDateformat.string(from: dateToConvert as Date)
    let objUTCDate: NSDate = objDateformat.date(from: strTime)! as NSDate
    let milliseconds: Int64 = Int64(objUTCDate.timeIntervalSince1970)
    let strTimeStamp: String = "\(milliseconds)"
    return strTimeStamp
}

To use

let now = NSDate()
let nowTimeStamp = self.getCurrentTimeStampWOMiliseconds(dateToConvert: now)