I have a value I would like to switch to another once a week either in the background on when the user launches the app on whichever day even if it's more than a week later. As the user uses the app during the week, each day turns a value e.g. variable b to false but every once a week I want to change that variable back to true for any day that it's been turned to false. I have a function I tried putting in the AppDelegate's didFinishLaunchingWithOptions but I am not precisely sure how to do the check and hence it didn't work. This is my attempt:
func resetOnSunday() {
let date = NSDate()
let formatter = NSDateFormatter()
let timeFormatter = NSDateFormatter()
formatter.dateFormat = "EEEE"
let WeekDay = formatter.stringFromDate(date)
timeFormatter.dateFormat = "HH:mm a"
let time = timeFormatter.stringFromDate(date)
if time >= "00:00 AM" && time <= "00:02 AM" && WeekDay == "Sunday" {
var b = true
}
}
Does anyone know how it can be done?
First of all, you can significantly cut down your code (and make it a lot more reliable) by using NSCalendar.
let date = NSDate()
let calendar = NSCalendar.currentCalendar()
//This will return a NSDate optional which you can check against.
let nextSunday = calendar.nextDateAfterDate(date, matchingUnit: .Weekday, value: 1, options: .MatchNextTime)
if date.timeIntervalSinceDate(nextSunday!) > 0 {
//Do your stuff here
}
Note that:
Weekday units are the numbers 1 through n, where n is the number of days in the week. For example, in the Gregorian calendar, n is 7 and Sunday is represented by 1.
Next, I would use NSUserDefaults for your value:
let defaults = NSUserDefaults.standardUserDefaults()
defaults.setBool(true, forKey: "yourVar")
//Then to read it
defaults.boolForKey("yourVar")
Related
What do we got: Date+time (format yyyy-mm-dd hh:mm a)
What are we looking for: Time difference in minutes
What operation: NewDate - OldDate
So, I wonder how I could accomplish above goal? I would like to format the date and time to US, regardless from which locale the user has. How can I do that?
Then I will save the 'oldTime' into UserDefaults, and use it for later calculation. The goal is to put the user on delay for 5 minutes and the calculations will be performed to determine if user should be on delay or not.
Just make a function that takes two dates and compares them like this.
import UIKit
func minutesBetweenDates(_ oldDate: Date, _ newDate: Date) -> CGFloat {
//get both times sinces refrenced date and divide by 60 to get minutes
let newDateMinutes = newDate.timeIntervalSinceReferenceDate/60
let oldDateMinutes = oldDate.timeIntervalSinceReferenceDate/60
//then return the difference
return CGFloat(newDateMinutes - oldDateMinutes)
}
//Usage:
let myDateFormatter = DateFormatter()
myDateFormatter.dateFormat = "yyyy-MM-dd HH:mm"
//You'll need both dates to compare, you can get them by just storing a Date object when you first start the timer.
//Then when you need to check it, compare it to Date()
let oldDate: Date = myDateFormatter.date(from: String("2019-06-22 11:25"))
func validateRefresh() {
//do the comparison between the old date and the now date like this.
if minutesBetweenDates(oldDate, Date()) > 5 {
//Do whatever
}
}
You can, of course, change the .dateFormat value on the date formatter to be whatever format you'd like. A great website for finding the right format is: https://nsdateformatter.com/.
You say:
I would like to format the date and time to US, regardless from which locale the user has. How can I do that?
Specify a Locale of en_US_POSIX:
let formatter = DateFormatter()
formatter.dateFormat = "yyyy-MM-dd hh:mm a"
formatter.locale = Locale(identifier: "en_US_POSIX")
The locale is not the only question.
There’s also a timezone question. For example, you're driving out of Chicago and go from Central to Eastern timezones; do you really want to consider that one hour has passed?
Do you really want to discard seconds? If you do that, the 59 seconds between going from 8:00:00pm to 8:00:59pm will be considered “zero minutes” but the one second between 8:00:59pm and 8:01:00pm will be considered “one minute”.
Frankly, if I wanted to save a locale and timezone invariant date string, I’d suggest using ISO8601DateFormatter.
Then I will save the 'oldTime' into UserDefaults, and use it for later calculation.
If that’s why you’re using this DateFormatter, I’d suggest saving the Date object directly.
UserDefaults.standard.set(oldTime, forKey: "oldTime")
And to retrieve it:
if let oldTime = UserDefaults.standard.object(forKey: "oldTime") as? Date {
...
}
In terms of calculating the number of minutes between two Date objects
let minutes = Calendar.current
.dateComponents([.minute], from: date1, to: date2)
.minute
If you want the number of seconds, you can also use timeIntervalSince:
let seconds = date2.timeIntervalSince(date1)
And if you wanted to show the amount of elapsed time as a nice localized string:
let intervalFormatter = DateComponentsFormatter()
intervalFormatter.allowedUnits = [.minute, .second]
intervalFormatter.unitsStyle = .full
let string = intervalFormatter.string(from: date1, to: date2)
I'm not convinced that your question is the best way to go about accomplishing your aim, but the code below will work.
let dateFormatterNow = DateFormatter()
dateFormatterNow.dateFormat = "yyyy-MM-dd hh:mm a"
dateFormatterNow.timeZone = TimeZone(abbreviation: "EST")
let oldDateString = "2019-06-23 12:44 p"
let oldDate = dateFormatterNow.date(from: oldDateString)
let newDateString = "2019-06-23 12:54 p"
let newDate = dateFormatterNow.date(from: newDateString)
if let oldDate = oldDate, let newDate = newDate {
let diffInMins = Calendar.current.dateComponents([.minute], from: oldDate, to: newDate).minute
print(diffInMins)
}
when i'm going set event from app to device calendar. i got wrong time.
i have three date picker one for date and other two for start time and end time for event. i set start date as end date in EKEvent because i have to set event on that day only.
get date from date-picker and store it as startdate and end date as nsdate type. below is my date-picker method
func pickerDate()
{
let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "YYYY-MM-dd"
routineStartDate = dateFormatter.string(from: self.startDatePicker.date)
// it is for database entry in string and i get right string
print(routineStartDate)
startDate = self.startDatePicker.date as NSDate
print(startDate)
endDate = startDate
}
below method is for start time where i get time and convert to Time Interval and set it to start date.
func starttime() {
let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "HH:mm"
let then: Date? = self.startTimePicker.date
let difference: TimeInterval? = then?.timeIntervalSinceNow
startDate.addingTimeInterval(difference!)
routineStartTime = dateFormatter.string(from: self.startTimePicker.date)
// it is for database entry in string and i get right string
print(routineStartTime)
}
below method is for end time where i get time from picker and convert to Time Interval and set Time Interval to enddate
func endtime() {
let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "HH:mm"
routineEndTime = dateFormatter.string(from: self.endTimePicker.date)
print(routineEndTime)
// it is for database entry in string and i get right string
let then: Date? = self.endTimePicker.date
let difference: TimeInterval? = then?.timeIntervalSinceNow
endDate.addingTimeInterval(difference!)
}
below image showing which date i set in picker
below is My EKEvent method where i create event.
existevent.title = tempDescription
existevent.startDate = startDate as Date
existevent.endDate = endDate as Date
existevent.isAllDay = false
existevent.notes = "This is a note"
existevent.calendar = cal
when i check event in calendar i got Problem, i get wrong time in event.i set start time 12:50 pm end time 1:50 pm on date 27 june 2017 in caledar app. date is set perfectly but why time is not set perfectly ? below image for calendar app.
i have doubt in conversion of time interval and set to date. but what i missing dont know.
please suggest me solution and ideas to solve.
Thank you
you need to convert the time to the desired time zone. Because now the date is set correctly in your timezone, but is displayed in +0000 Screenshot. Use calendar for date representation this
And change your code like this in both methods:
startDate.addingTimeInterval(difference!)
to
self.startDate = startDate.addingTimeInterval(difference!)
and
endDate.addingTimeInterval(difference!)
to
self.endDate = endDate.addingTimeInterval(difference!)
in your case Xcode Warning "Result of call to 'addingTimeInterval' is unused"
Try to convert date, before set it to you "existevent", or when you show it
func convertDate(date:Date) -> Date {
let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "HH:mm" // or other format
var comp = DateComponents()
let calendar = Calendar.current
comp.hour = Calendar.current.component(.hour, from: date)
comp.minute = Calendar.current.component(.minute, from: date)
comp.timeZone = TimeZone(abbreviation: "GMT")!
return calendar.date(from: comp)!
}
I'm making a kind of challenge based app that requires that the user comes back every day. If he misses one day, he has to start all over again.
My problem is my dateChanged()-function; the first thing is, that it doesn't work very reliable, the second is that I just check if the date changed, I accordingly don't know if there were one or two days between using the app.
Here's my current function:
public func changeDays()
{
myFormatter.dateStyle = .short
myFormatter.locale = Locale(identifier: "de_DE")
oldDate = defaults.string(forKey: "oldDate")!
let newDate = Date()
let newDateString = myFormatter.string(from: newDate)
if newDateString == oldDate
{
NumberOfDaysInARow.text = "\(days) / 30"
}
else if newDateString != oldDate
{
days += 1
NumberOfDaysInARow.text = "\(days) / 30"
defaults.set(days, forKey: "days")
}
oldDate = newDateString
defaults.set(oldDate, forKey: "oldDate")
}
Just today it started giving me a fatal error when starting the app on my iPhone, did not happen in the simulator though... weird.
How do I have to change my function to make it a 100% reliable (and working) while also being able to check the amount of time between the two dates?
Thank you for having a look! Have a great day
You could extend Date with the function below that returns the amount of days from another date.
extension Date {
// Returns the amount of days from another date
func days(from date: Date) -> Int {
return Calendar.current.dateComponents([.day], from: date, to: self).day ?? 0
}
}
Instead of saving oldDate as a string you can set it to defaults as a date:
defaults.set(Date(), forKey: "oldDate")
You can get the old date from defaults using:
let oldDate = defaults.object(forKey:"oldDate") as! Date
Once you have your old date
let dateNow = Date()
let timeDifference = dateNow.days(from: oldDate!)
If timeDifference > 1 {
// older than 1 day
} else {
// Streak still alive
}
}
If you look in the documentation you will see that Date has a method whose sole purpose is too determine the interval between two dates timeIntervalSince(_:).
If you set the old date to always be 11:59PM on the day it was last used you only have to see if the interval is greater than 24 hours worth of seconds (60 seconds * 60 minutes * 24 hours).
You may want to look at the docs for DateComponents for help creating a date that uses the current date but with a specific time.
I am making a social app that saves its posts in user specific nodes , with that i am also saving the time of post in this format :-
Wednesday, July 20, 2016, 00:14
which i display with the post in the global feed of friends of the user.
Before 24 hours of that post , i want to display time of post on the feed as this :- "5 Hours Ago"
After 24 hours of that post time of post becomes something like this :- "Yesterday"...
After 48 hours of that post time of post becomes something like this :- "On 5 Aug"...
So far i have come up with these two options:-
1.) Change the time of the feed in the database, which i think would be much better option.
2.) Retrieve the time of post , iterate through MULTIPLE if conditions and set the time of post accordingly.
I would be able to implement the second option but i have no clue to how to go forward with option one
Given that my JSON tree is something like this
appname:{
users : {....
.....
user1 : {....
.....
postsCreated : {
post1 : {
..
timeofPost : ""Wednesday, Aug 5, 2016, 00:14""
}
}
}
}
}
I did stumble upon http://momentjs.com/ but thats for Javascript
Also any suggestion on my JSON tree or is it fine the way it is?
You propose:
Change the time of the feed in the database, which i think would be much better option.
No, the date in the database, as well as that which is communicated with web service, should not be a formatted string. The database and the web service should be capturing the raw dates (or, more accurately, RFC3339/ISO8601 format or seconds from some reference date). The formatting of the elapsed time in a string for the UI is the responsibility of the app.
Retrieve the time of post, iterate through MULTIPLE if conditions and set the time of post accordingly.
Yes, that's what you should do.
By the way, if you're going to omit the year, you probably have a fourth permutation which includes year if the date is more than one year in the past, e.g.:
func formattedPostDateString(date: NSDate) -> String {
let now = NSDate()
let elapsed = NSCalendar.currentCalendar().components([.Day, .Year], fromDate: date, toDate: now, options: [])
switch (elapsed.year, elapsed.day) {
case (0, 0):
return "\(elapsedFormatter.stringFromDate(date, toDate: now)!) \(agoDateString)"
case (0, 1):
return yesterdayString
case (0, _):
return "\(onDateString) \(lessThanOneYearFormatter.stringFromDate(date))"
default:
return "\(onDateString) \(moreThanOneYearFormatter.stringFromDate(date))"
}
}
Where
let onDateString = NSLocalizedString("On", comment: "prefix used in 'On 5 Aug'")
let agoDateString = NSLocalizedString("ago", comment: "suffix use in '4 hours ago'")
let yesterdayString = NSLocalizedString("Yesterday", comment: "showing 'date' where it's between 24 and 48 hours ago")
let elapsedFormatter: NSDateComponentsFormatter = {
let formatter = NSDateComponentsFormatter()
formatter.allowedUnits = [.Year, .Month, .Day, .Hour, .Minute, .Second]
formatter.unitsStyle = .Full
formatter.maximumUnitCount = 1
return formatter
}()
let lessThanOneYearFormatter: NSDateFormatter = {
let formatter = NSDateFormatter()
formatter.dateFormat = NSDateFormatter.dateFormatFromTemplate("MMM d", options: 0, locale: nil)
return formatter
}()
let moreThanOneYearFormatter: NSDateFormatter = {
let formatter = NSDateFormatter()
formatter.dateStyle = .MediumStyle
return formatter
}()
The only thing you need to do is to convert the string returned by the web service into NSDate object. To that end, the web service should probably return the post date in ISO 8601/RFC 3339 format (e.g. 2016-08-26T15:01:23Z format).
To create ISO8601/RFC3339 dates in Swift 2:
let isoDateFormatter: NSDateFormatter = {
let formatter = NSDateFormatter()
formatter.locale = NSLocale(localeIdentifier: "en_US_POSIX")
formatter.timeZone = NSTimeZone(forSecondsFromGMT: 0)
formatter.dateFormat = "yyyy-MM-dd'T'HH:mm:ssZZZZZ"
return formatter
}()
And then:
let string = isoDateFormatter.stringFromDate(date)
Or
let date = isoDateFormatter.dateFromString(string)
Or in iOS 10+ using Swift 3, you can use the new ISO8601DateFormatter:
let isoDateFormatter = ISO8601DateFormatter()
I have a dictionary like this:
var dic = [NSDate: Int]()
it is used in my iOS to-do app to get the number of finished tasks of a particular date. I only care about the year, month and day sections in NSDate and also want to be able to get the number of tasks in a particular date using this dictionary, how can I do that? thanks.
Instead of storing your date as NSDate in your dictionary you can save it as String so that comparison will be easier. Use following code to store it as a string
func dateFromString(date : NSDate) -> String {
var dateFormatter = NSDateFormatter()
dateFormatter.dateFormat = "yyyy-MM-dd"
return dateFormatter.stringFromDate(date)
}
You can pass NSDate() to above function and it will give you string containing only year, month and date. For retrieving your data from dictionary use following.
func dateFrom(year:Int, month:Int, day:Int) -> String {
let components = NSDateComponents()
components.year = year
components.month = month
components.day = day
let gregorian = NSCalendar(identifier:NSCalendarIdentifierGregorian)
let date = gregorian!.dateFromComponents(components)
return dateFromString(date!)
}
You can pass year, month and date to above function and it will return corresponding date in string format. So your dictionary operations will look like
dict[dateFromString(NSDate())] = 1 //for insertion or updation
let numOfTasks = dict[dateFrom(2016, month: 1, day: 15)] //to get task for any particular day
EDIT
If you want to proceed with NSDate as key for your dictionary then you'll have to modify above code as follows. dateFrom will return date with year,month and date of your choice, and time will be some constant value. Time will be set to midnight in your current time zone if you don't set it.
func dateFrom(year:Int, month:Int, day:Int) -> NSDate {
let components = NSDateComponents()
components.year = year
components.month = month
components.day = day
let gregorian = NSCalendar(identifier:NSCalendarIdentifierGregorian)
let date = gregorian!.dateFromComponents(components)
return date!
}
And for getting current date use following so that you store date object with current year, date, month and time to some constant value.
func getCurrentDate()->NSDate {
let date = NSDate()
let calendar = NSCalendar.currentCalendar()
let components = calendar.components([.Day , .Month , .Year], fromDate: date)
return dateFrom(components.year, month: components.month, day: components.day)
}
Usage will be as follows
dict[getCurrentDate()] = i //for insertion or updation
let numOfTasks = dict[dateFrom(2016, month: 1, day: 15)] //to get task for any particular day