I have a separate DatePicker and TimePicker component in my app.
Once the user has selected both the desired Date and Time, I construct a new Date object like this:
let timeStamp = Date(year: selectedDate.year, month: selectedDate.month, day: selectedDate.day, hour: selectedTime.hour, minute: selectedTime.minute)
I then use DateFormatter to output the exact time that the user has selected like this:
let formatter = DateFormatter()
formatter.dateFormat = "HH:mm"
formatter.string(from: timeStamp)
Now I have a very weird bug where sometimes time output will be correct (time will be displayed in UTC+2) and sometimes it'll be incorrect (time will be displayed in UTC+1) and I have absolutely no idea what could be causing this.
Example 1 (correct output):
User selects: May 26, 2020 - 18:38
Date ISO output: "2020-05-26T16:38:00Z"
DateFormatter output: "18:38"
This is the correct output
Example 2 (wrong output):
User selects: March 26, 2020 - 18:38
Date ISO output: "2020-03-26T16:38:00Z"
DateFormatter output: "17:38"
This is not the correct output. Time should be 18:38 like in the above example.
Someone please tell me how is this possible? Literally the only difference is user picked March instead of May (different month) and that for some reason confuses the DateFormatter, so Time output is in a different timezone.
I am using SwiftDate to work with dates in general.
Set correct formatter.locale, you can try Locale(identifier: "en_US_POSIX") or try to use formatter.timeZone property. Maybe TimeZone.current or TimeZone(secondsFromGMT: 0) will fix your problem
That is probably because in May daylight saving is in effect and the difference to UTC changes from +1 to +2 hours
You can use the current TimeZone and add configure your DateFormatter with it
let timezone = TimeZone.current
dateFormatter.timeZone = timezone
That should make sure that you always use the same timezone that is currently used by your device
Related
I have a time coming from service in string form like so "12:30 PM".
I am able to get this time but I want to add this time in current date. like so
31/3/2021 12:30 PM
The current date is in date object and coming time is in string format.
Please let me know what is a right way to do so? I am right now taking 12, 30,from string and setting it via Calendar. But dont know how to set am pm . Please let me know how to append time with date object. Thanks in advance.
First, if that is the date string you are getting from your service, it is incomplete. It needs a time zone.
Here's what I would do:
Assuming the service always uses the same time zone, find out that time zone.
Create a date formatter for that date string format, including the AM/PM bit.
Set the date formatter to use the time zone from step 1.
Convert the date string to a Date object using your DateFormatter.
Use the current calendar to extract the hours and minutes values into a DateComponents object.
Get the current date, and use the Calendar function date(bySettingHour:minute:second:of:matchingPolicy:repeatedTimePolicy:direction:) to set the hour and minutes of the current date to the values you got from step 5.
You should search in the Xcode help system for:
Dates and Times (overview)
Calendrical calculations (discussion specific to doing math on dates and times)
DateFormatter. (See this article for info on the characters to use to build your dateFormat string.)
Calendar
DateComponents
Calendar
You can do this by setting up your DateFormatter with the correct timeZone, calendar, defaultDate, and dateFormat. Here's an example:
import Foundation
let parser = DateFormatter()
parser.calendar = Calendar(identifier: .gregorian)
parser.timeZone = TimeZone(identifier: "US/Eastern")!
parser.defaultDate = parser.calendar!.date(
from: DateComponents(
timeZone: parser.timeZone!, era: 1,
year: 2021, month: 3, day: 31,
hour: 12, minute: 0, second: 0))!
parser.dateFormat = "hh:mm a"
print(parser.date(from: "12:30 PM"))
Output:
Optional(2021-03-31 16:30:00 +0000)
Hi there in my app I need to filter some documents through date. I need to see if the first date is the same day of the second date, so I searched on Apple Documentation to see if there are a solution to do this without create a method and I found this instruction isDate(_:inSameDayAs:), but if i try to compare the following date:
2020-07-29 16:15:50 +0000
2020-07-29 22:00:00 +0000
As you can see the day is the same, but I'm not able to understand why it return false, what's wrong?
CODE
Here's my code to check the difference between days:
myArray.filter({Calendar.current.isDate($0.log.createdDate, inSameDayAs:date)})
Date represents instants in time. Two instants of time could be in the same day in one timezone, but not in the same day in another timezone. These two instants in time:
2020-07-29 16:15:50 +0000
2020-07-29 22:00:00 +0000
are in the same day in the UTC timezone. However, in a timezone where the offset is 5 hours ahead of UTC (UTC+5) for example, the two times will not be in the same day, because they will become:
2020-07-29 21:15:50
2020-07-30 03:00:00
in that timezone
Now you should see that the timezone is crucial at determining whether two dates are in the same day.
Calendar.current uses the local timezone of the device for almost everything it does. isDate(_:inSameDayAs:) is no exception. In your device's timezone, the two dates are not in the same day. However, when you print them out without a formatter, they are always printed in the UTC timezone. In the UTC timezone, they are in the same day, making you think Calendar.current is wrong. Assuming you actually want to see if the two dates are in the same day in your device's timezone, then Calendar.current is right, and you don't need to fix anything.
To print the two dates in your timezone, use a formatter:
let formatter = DateFormatter()
formatter.dateStyle = .long
formatter.timeStyle = .long
print(formatter.string(from: yourDate))
If you actually want to see if the two dates are in the same UTC day, then you can set the timezone of the Calendar:
var calendar = Calendar.current
calendar.timeZone = TimeZone(identifier: "UTC")!
// call calendar.isDate(_:_sameDayAs:) rather than using Calendar.current
I am struggle with timezone because I tried to set time to midnight to 23:00:00, however, the result show start with 6am until 5am next day. I tried to set timezone to current, still same result. Here my code
let day1num = Int(todaynumber.string(from: Date()))! + 1
let day1start = Calendar.current.date(bySetting: .day, value: day1num, of: Date())
let day1end = Calendar.current.date(bySetting: .hour, value: 23, of: day1start!)
print("\(day1start!) to \(day1end!)")
I got result
2020-04-22 06:00:00 +0000 to 2020-04-23 05:00:00 +0000
I don't want 6am to 5am next day, I want result:
2020-04-22 00:00:00 +0000 to 2020-04-22 23:00:00 +0000
How can I solve it?
Thanks!
Your issue is you're misunderstanding Date and how it prints to the console.
Dates are representative of moments in time. Think of them as an Integer that represents the amount of time that has passed since a reference date. It's NOT a human-readable string. To convert a date to a human-readable string, you need to use a DateFormatter and make sure to set the timeZone of the date formatter to be the time zone in which you want the string to be representative of (it will default to the system's current time zone). The timeZone will impact what the resulting string is. For example, if you have a date formatter where the time zone is Pacific time, it might return a value like April 22, 2020 6:00 PM, but then if you change the time zone to mountain time and get the string from the date, it will return April 22, 2020 7:00 PM.
When you print a Date instance to the console, the system formats it to be a human-readable string in the UTC time zone. If I'm doing my math correctly, you're in mountain time, which is why the value you're seeing logged is 6 hours ahead of the value you're expecting.
If you want to see the date logged to the console as the user will see it, you should use a DateFormatter instance. It will default to use the user's system time zone, then use the Date value you've calculated to get the String representation of that date, and then log that String to the console, rather than the date itself.
let formatter = DateFormatter()
formatter.dateStyle = .medium // Customize as needed
formatter.timeStyle = .medium // Customize as needed
// formatter.timeZone = ... something else if you don't want to use the system time zone
let day1StartAsString = formatter.string(from: day1start!)
let day1EndAsString = formatter.string(from: day1end!)
print("\(day1StartAsString) to \(day1EndAsString)")
I am trying to convert Date object in string using DateFormatter but I am getting some weird behavior. I have a timestamp value (1513356296) which I want to convert in 24hour format along with date and timeZone (My current is -0800). Here is my code:
let date = Date(timeIntervalSince1970: Double(1513356296))
let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ssZ"
dateFormatter.timeZone = TimeZone(secondsFromGMT: -(8*3600))
dateFormatter.locale = Locale.current
I am expecting a result value of 2017-12-15T08:44:56-0800 but I am getting 2017-12-15T8:44:56-0800. Everything is same except the hour value. The hour value is 8 instead of 08.
This is not happing with all the test, it happened in only one device and rest are fine.
I also tried by checking if hour value changes if I change device time setting to 12hour format from 24hour format to see what I get for HH and it was always giving me 08 in my case. Only one user was facing this issue.
What's wrong with my code? or is there something wrong with HH I am using?
For 2015,July,3 it is Friday, but my app on some user's iphone devices just return Thursday,which is obviously wrong.
Just wonder why this happened ? How to fix it ?
Thanks,
We need use NSDateFormatter to return the weekday for given date. In my case, the given date is converted to UTC, but didn't set the time zone as UTC, that will cause problem to display wrong weekday in some country with different time zone.
So the fixing solution is to set up the date formatter with correct time zone.
formatter.timeZone = NSTimeZone(abbreviation: "UTC") // my case date is UTC