I am currently creating an app where I ask the user to input a time (through datePicker) and send the user a notification every day on that time.However, I noticed that datePicker only has an NSDate object, and was wondering if there was a Time object counterpart.Also, would this Time object be a good way of storing the time, or should I convert the hour and minutes to Integers for storage?
Thanks in advance!
NSDate also contains Time information within it. You can store the exact date and time using only NSDate.
NSDate is a generic representation independent of any time zone. According to the apple docs:
NSDate objects encapsulate a single point in time, independent of any particular calendrical system or time zone. Date objects are immutable, representing an invariant time interval relative to an absolute reference date (00:00:00 UTC on 1 January 2001)
NSDate is basically the number of seconds from the reference date mentioned above.
And yes NSDate is the best way for storing time and date information in your app.
Whenever you want to display the time, use NSDateFormatter to format the date and time into any format you desire and for any Time Zone you require.
Swift 3
The NSDate class has been renamed to Date in Swift 3
Related
I am new to this iOS world, trying to learn how to handle dates and time.
Imagine I have a Class Shop. The shop have time-intervals which represent the open and close time for each day of the week.
Some context data (example string from database, GMT Timezone):
Monday: "08:00:00-13:00:00, 15:00:00-18:00:00"
Tuesday:"09:00:00-13:00:00, 15:00:00-19:00:00"
Wednesday: "15:00:00-23:59:59"
Thursday: "00:00:00-08:00:00"
etc..
Monday for example would have to store 2 time-intervals.
My question is how can I store this data (array of DateIntervals? TimeIntervals? or another more suitable class?) in a Class and get the current time to check if the store is opened or not.
The native date format for iOS (and Mac OS) is the Date object. A Date object represents and instant in time, independent of time zone. You then use a DateFormatter to convert a date to a string representation in a particular time zone.
In your case, though, you need to represent timer ranges for days of the week on a variety of different dates.
You should read the Calendar class reference in the Xcode documentation. Of particular interest would be the date(bySetting:value:of:) method, which will let you start from a given date and calculate a new date by changing the value of various date components.
You have a set of time intervals for each day. So you need a way to store, for a given day of the week, one or more time intervals. Your time intervals have a start time and an end time. Each of those needs to be represented by an hour, minute, and optionally second.
With that information you can get the current date/time and split it into components. Get the weekday, hour, minute, and second. Using the weekday you can get the appropriate time intervals. Then you can iterate those intervals and see if the current hour, minute, second falls between one of the intervals.
This all assumes that for a given business, your time intervals (open times) are specified in local time for the given business.
When converting the current date/time into its components, you should ensure that you set the calendar's timezone to match the timezone of the business in question.
There is no need for any date comparisons for any of this. You want to compare hours/minutes/seconds of the current date with the hours/minutes/seconds of the open times.
I have a Date column in my Sqlite database. When I put some NSDate value in it, and open the Sqlite file through graphical tools. I get some value like 530963469.705571. The corresponding date is around today or yesterday.
It's clearly not Unix epoch datestamp value. What exactly does this value mean?
I need to change this value in order to debug my app.
From the documentation
NSDate objects encapsulate a single point in time, independent of any particular calendrical system or time zone. Date objects are immutable, representing an invariant time interval relative to an absolute reference date (00:00:00 UTC on 1 January 2001).
Since sqlite does not support NSDate directly, the date is persisted as the underlying value. 530963469.705571 represents the number of seconds between 00:00:00 UTC on 1 January 2001 and the time when you created the NSDate
You can use the NSDate initialiser init(timeIntervalSinceReferenceDate:) to create an NSDate from the time interval value.
In my program, I have an NSArray of various dates and times, stored as strings and formatted like this: #[#"07:23",#"18:09",#"13:55"];
When I use an NSDateFormatter to convert these to NSDates, the times are correct, but year/month/day information is added.
The arrays that I have created are columns of a bus schedule. Each entry is one timeslot for whatever stop the array represents. My application needs to take the current time: [NSDate date] and see which time from the array is next in sequence. I'm just trying to display when the very next bus will arrive.
I have thought of comparing each element of the array with the current date and time using -[NSDate's laterDate:], but the problem is that when I convert the strings to NSDate objects, it gives them some random day-month-year like 13:55:00 January 1st, 2001 which will always be before the current date, so my test won't work.
I can find some workarounds that are really tragically McGuyvered but I would prefer something clean.
What I want to know are these things:
Can I remove the day/month/year portion from the NSDate?
Is it possible to easily set the day/month/year of each object in my array to today without using NSDateComponents and NSCalendar? I can manipulate them as they enter the array.
Would it be easier to reformat the current date/time to match the day/month/year of the array?
Otherwise, is there a better, cleaner solution to find the next upcoming timeslot? I am open to changing the entire format from arrays if necessary.
Can I remove the day/month/year portion from the NSDate?
No. An NSDate is merely an instant in time that is some number of seconds since some reference date. Describing that instant in time as some year/month/day depends on the local calendar. For example, the "day of month" of [NSDate date] as I type this is 28 where I live but 29 for the same NSDate value in Japan.
Is it possible to easily set the day/month/year of each object in my
NSMutableArray to today? without using NSDateComponents and
NSCalendar?
No. That's what NSDateComponents is for.
Otherwise, is there a better, cleaner solution to find
the next upcoming timeslot? I am open to changing the entire format
from arrays if necessary.
Use NSCalendar's -components:fromDate: to get an NSDateComponents object that matches [NSDate date]. Replace the hour/minute/second components with an arrival time's hour/minute/second: this is an arrival time today. Add one to the day component: this is an arrival time tomorrow. (Weekend and holiday schedules cause extra complication; the weekday component may be useful.) Convert back to NSDate using NSCalendar's -dateFromComponents: and perform your date comparisons there.
I get current time or time stamp of some image. I have to change only date while the time should not be changed. For example I use [NSdate date] to get current date and time and store in an NSdate object that is "2014-01-10 09:58:47 +0000". Now change only the date part, keeping the time same as it is "2013-11-09 09:58:47 +0000"
How can I achieve that?
Convert the date into it's date components (which includes the time part), change the date part of the components to be for the new day, and create a new date based on these components.
dateByAddingDateComponents is also another way to do it.
It's all described in the Calendrical Calculations documentation.
I have a Time Picker and a Date Picker.
How to get the time included with the date in same NSDate?
I need the time between 2 dates (including time) How?
I have the code for getting time between dates, i just need help to include the time.
By default, a UIDatePicker is set to allow the user to choose a Date and a Time. The mode can be set to either Date, Time or Date and Time. As long as the mode of your UIDatePicker is set to Date and Time it will set both the date and time in the linked NSDate object.
If you really want to have two separate UIDatePickers, one set to Date and the other to Time then you will need to link them to two different NSDate objects and then have code behind to combine the two NSDates into a single NSDate using something like the code here Problem combining a date and a time into a single NSDate