How to format date from 12h to 24h in SwiftUI? - swift

Question

I am trying to format a 12h date to 24h date, but is not working, maybe I am doing something wrong. I'll share the code below so maybe you can help me.
"syncViewModel._order.deliveryDate" is the date that I am getting from the backend and is a string.
Text(dateFormatTime(date: syncViewModel._order.deliveryDate ?? ""), style: .time)
func dateFormatTime(date : String) -> Date {
let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ss"
dateFormatter.timeZone = .current
dateFormatter.locale = NSLocale(localeIdentifier: "en_GB") as Locale
return dateFormatter.date(from: date) ?? Date.now
}
This is the format of my date : 2022-01-25T17:00:00

Answer 1

You use a date formatter to convert a date string to a Date. You can then use an additional date formatter, to directly return the time in the format that you want, as a string:
func timeIn24HourFormat(from date: Date) -> String {
let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "HH:mm"
return dateFormatter.string(from: date)
}
That way you can use it in SwiftUI directly, without requesting the time style:
Text(timeIn24HourFormat(from: dateFormatTime(date: "2021-07-14T17:00:00")))

Answer 2

In addition to Jorge's answer, I edited the code to be able to accept a Bool to change between 12 and 24 hour format so the user can choose.
struct DateFormat {
// Change time from 12 hour to 24 hour format
static func timeHourFormat(from date: Date, twentyFourHourFormat: Bool) -> String {
let dateFormatter = DateFormatter()
dateFormatter.dateFormat = twentyFourHourFormat ? "HH:mm" : "hh:mm"
return dateFormatter.string(from: date)
}
}
Then to apply the change (in SwiftUI) you can save the state first with:
#AppStorage("twentyFourHourFormat") var twentyFourHourFormat = true
And call the function with
Text(DateFormat.timeHourFormat(from: myDateTime ?? Date.now, twentyFourHourFormat: twentyFourHourFormat))
Just choose a toggle button or some or conditional setter to change between true and false.
myDateTime is taken from a Core Data return, hence the optional binding within the function call, but you can omit this and the ?? just use Date.now.