How to store date in userdefaults?

Question

I'd like to record the history of her entry into the textfield. I intend to register this with UserDefaults. But when I try to save it with UserDefaults, "cannot assign value of type 'nsdate'?'to type 'String' " Error. I don't think it's accepting textfield data because it's string. And how can I keep history in memory?

formatteddate and formatteddate2 give this error. The date output is as follows : 20/04/2019 20:23

let token = try? keychain.getString("chipnumbernew")
        chip1InfoString = token

        var time = NSDate()
        var formatter = DateFormatter()
        formatter.dateFormat = "dd/MM/yyyy HH:mm"
        var formatteddate = formatter.string(from: time as Date)
        var formatteddate2 = formatter.string(from: time as Date)

        timertextNew.text = formatteddate
        timertext2New.text = formatteddate2


        let RetrivedDate = UserDefaults.standard.object(forKey: "timertext") as? NSDate

       formatteddate = RetrivedDate

        let RetrivedDate2 = UserDefaults.standard.object(forKey: "timertext2") as? NSDate
        formatteddate2 = RetrivedDate2

score 76 · Accepted Answer · answered Apr 20 '19 at 19:57

If you only want to display the date value you can convert and store it as string otherwise you convert/format it after you have read it, either way you should make sure you use the same type when saving and reading

//save as Date
UserDefaults.standard.set(Date(), forKey: key)

//read
let date = UserDefaults.standard.object(forKey: key) as! Date
let df = DateFormatter()
df.dateFormat = "dd/MM/yyyy HH:mm"
print(df.string(from: date))

// save as String
let df = DateFormatter()
df.dateFormat = "dd/MM/yyyy HH:mm"
let str = df.string(from: Date())
UserDefaults.standard.setValue(str, forKey: key)

// read
if let strOut = UserDefaults.standard.string(forKey: key) {
    print(strOut)
}

score 55 · Answer 2 · answered Jul 21 '20 at 17:01

The following saves a Date object as a Double (a.k.a. TimeInterval). This avoids any date formatting. Formatting can lose precision, and is unnecessary since the string is not intended for users to read.

// save
UserDefaults.standard.set(Date().timeIntervalSince1970, forKey: key)

// read
let date = Date(timeIntervalSince1970: UserDefaults.standard.double(forKey: key))

score 2 · Answer 3 · answered Oct 30 '21 at 12:16

you can always create an extension for saving and retrieving the date in userdefault. here the example code:

import Foundation

extension UserDefaults {
    func set(date: Date?, forKey key: String){
        self.set(date, forKey: key)
    }
    
    func date(forKey key: String) -> Date? {
        return self.value(forKey: key) as? Date
    }
}

let userDefault = UserDefaults.standard
userDefault.set(date: Date(), forKey: "timertext")
print(userDefault.date(forKey: "timertext") ?? "")

score 0 · Answer 4 · answered Apr 20 '19 at 17:57

0

Your problem is that you are retrieving NSDate from the user default storage and then trying to assign them to a String (formatteddate).

Try this;

  formatteddate = formatter.string(from: RetrivedDate as Date)

answered Apr 20 '19 at 17:57

john elemans

2,578
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I have to put it on the string, it's okay to keep it in memory. – stakabekor Apr 20 '19 at 19:22

How to store date in userdefaults?

4 Answers4