I need to compair current time with two time rang, its work fine in every case but when I check "12:00 PM" to "01:30 PM", it give me wrong value.
NSComparisonResult timeStart=[#"01:02 PM" compare:#"12:00 PM"];
NSComparisonResult timeEnd=[#"01:02 PM" compare:#"01:30 PM"];
both timeStart and timeEnd are -1?
where timeStart is bigger so it should be 1 which is not.
Please help......
You are comparing two strings, not two times. You need to first construct NSDate objects with say NSDateFormatter's dateFromString: method, then do your comparison.
Related
I have a timestamp measured in milliseconds since January 1, 1970, 00:00:00 UTC.
eg. input "takeoffTime": "1396614600000"
output in date format
You can do this by doing the following:
[NSDate dateWithTimeIntervalSince1970:1396614600000/1000];
This will give you 2014-04-04 12:30:00 +0000. You should read up on how to pass messages (call methods) here: How can I call a method in Objective-C?
The NSDate class gives you this method + (instancetype)dateWithTimeIntervalSince1970:(NSTimeInterval)seconds.
Look here: Apple docs
NSString* takeOffTime = #"1396614600000";
double miliSec = takeOffTime.doubleValue;
NSDate* takeOffDate = [NSDate dateWithTimeIntervalSince1970:miliSec/1000];
I want to convert a date string (can be in any time zone) to a date in French Time Zone. I am using following code.
NSString * dateString = #"27/05/2015 - 19:00" // system time zone is GMT +5
NSDateFormatter* frenchDateFormatter = [[NSDateFormatter alloc] init];
[frenchDateFormatter setTimeZone:[NSTimeZone timeZoneWithName:#"Europe/Paris"]];
[frenchDateFormatter setDateFormat:#"dd/MM/yyyy - HH:mm"];
NSDate *frenchDate = [frenchDateFormatter dateFromString:dateString];
NSLog(#"%#",frenchDate);
NSString * frenchString = [frenchDateFormatter stringFromDate:frenchDate];`
Elaboration
--> System time zone is GMT +5
--> French time zone is GMT +2
Date string = 27/05/2015 - 19:00
Expected result = 27/05/2015 - 16:00
Actual result (NSDate) = 2015-05-27 17:00:00 +0000
Actual result (NSString from date) = 27/05/2015 - 19:00
Kindly point out if I am missing something
If you use NSLog to display dates it'll be displayed in UTC. So either you have to convert in your head, or don't use it. I wrote a long answer explaining this to a different question.
Because you have set the timezone of your parsing dateFormatter to Paris the string you parse is treated as "time in paris". That's your problem, you actually wanted to parse it in local time.
The results you get are exactly as one would expect.
You create a NSDate that relates to "19:00 in Paris". Since Paris is UTC+2 that date is 17:00 in UTC (or in +0000). If you convert that date back to "time in Paris" you end up with the same string as before.
If you want to convert the representation of a point in time in your location to a different representation at a different location you have to use two dateFormatters.
NSString *localDateString = #"27/05/2015 - 19:00" // system time zone is GMT +5
NSDateFormatter* localDateFormatter = [[NSDateFormatter alloc] init];
[localDateFormatter setTimeZone:[NSTimeZone localTimeZone]];
[localDateFormatter setDateFormat:#"dd/MM/yyyy - HH:mm"];
NSDate *date = [localDateFormatter dateFromString:localDateString]; // date contains point in time. It no longer has a timezone
NSDateFormatter* franceDateFormatter = [[NSDateFormatter alloc] init];
[franceDateFormatter setTimeZone:[NSTimeZone timeZoneWithName:#"Europe/Paris"]];
[franceDateFormatter setDateFormat:#"dd/MM/yyyy - HH:mm"];
NSString * timeInFranceString = [franceDateFormatter stringFromDate:date]; // representation of the point in time from above for people in Paris
This line prints out the date/time in GMT, as it calls [NSDate description], and there is a potential difference between systemTimeZone and GMT, hence the difference you are seeing:
NSLog(#"%#",currentDate);
If you want to see what the date/time is for a particular timezone then use the NSDateFormatter object to get the string.
A date doesn't have a time zone information. A date is internally represented as a number. We don't have to know anything about that number (it's a number of seconds from a fixed date in UTC), the important thing is to understand that to display a date to a user, you have to convert it to a string first.
A string representation of a number is generated from a date using a date format and a time zone. For all date -> string and string -> date conversions you can use NSDateFormatter.
You have successfully parsed currentDate from your string representation. If you want to reverse the process and get the string representation, just use [currentDateFormatter stringFromDate:currentDate]
Check at http://www.timeanddate.com/worldclock/
Right now Paris is two hours ahead of UTC. The result is absolutely correct. NSDate keeps dates in UTC. The idea is that if any two people look at their watch at the same moment, and convert the time they see on their watch to NSDate, they will get the same result.
You cannot get an NSDate for a timezone. NSDate doesn't support time zones. The only way to get a date with a time zone is to use NSDateFormatter to convert it to a string.
I need to show a date in concrete time zone including DST (European time). App will be used in Lithuania, so time zone is +3 at summer and +2 at other time. The thing is, I have just a list of dates and I don't know how to show +3 for summer dates and +2 for other dates. Currently, I have time zones:
// Eastern European Summer Time UTC + 3 hours
NSTimeZone *timeZoneWithDst = [NSTimeZone timeZoneWithAbbreviation:#"EEST"];
//Eastern European Time UTC + 2 hours
NSTimeZone *timeZoneWithoutDst = [NSTimeZone timeZoneWithAbbreviation:#"EET"];
But how to loop through my list of dates and calculate should I add +3 or +2 to date?
UPDATE Finally I got it working by applying Martin R. suggestion to use time zone by name, not by abbreviation. In this way, date with this time zone handles DST automatically. Here's my code for converting dates:
NSTimeZone *TimeZone = [NSTimeZone timeZoneWithName:#"Europe/Vilnius"];
NSInteger seconds = [myTimeZone secondsFromGMTForDate:someDate];
NSDate *result = [NSDate dateWithTimeInterval:seconds sinceDate:someDate];
To convert an NSDate to a string representation, use NSDateFormatter. By default, it uses the local time zone. To display the date according to a concrete time zone, you can set
NSTimeZone *tz = [NSTimeZone timeZoneWithName:#"Europe/Vilnius"];
[dateFormatter setTimeZone:tz];
(According to http://www.timezoneconverter.com/cgi-bin/findzone, the time zone for Lithuania is "Europe/Vilnius".)
This is a very similar alternative that worked for me, in Swift:
var currentDate: NSDate {
let currentLocalTime = NSDate()
let localTimeZone = NSTimeZone.systemTimeZone()
let secondsFromGTM = NSTimeInterval.init(localTimeZone.secondsFromGMT)
let resultDate = NSDate(timeInterval: secondsFromGTM, sinceDate: currentLocalTime)
return resultDate
}
i have a current date using NSDate which is ma start date....and i add 4 more days to the current date where i get ma endDate..
NSString *StrtDate= [dateFormatter stringFromDate:[NSDate date]];
int daysToAdd = 4;
NSDate *newDate1 = [[NSDate date] dateByAddingTimeInterval:60*60*24*daysToAdd];
NSString *StopDate= [dateFormatter stringFromDate:newDate1];
suppose the current date is todays date..thats 28th of jan the end date becomes 32nd of Jan which is invalid rite?
how do u validate the date??
Have you run the code and checked whether the resultant date is indeed 32nd January?
The framework is intelligent enough to understand valid dates. You will get correct date.
You don't need to worry about this as the date framework knows how many days are in each month.
I want to get a time string like "10:00 PM", and I use the NSDateFormatterShortStyle to achieve this.
However when the system is set to use 24-hour format, what I got is "22:00".
Besides, I want to get a localized time string. For example, in Chinese, I want to get "下午10:00" instead of "10:00 PM". So I have to use the [NSLocale currentLocale], and can't use the en_US_POSIX locale.
Please help me to get a localized 12-hour format time string.
I need not only the hour part, and also the am/pm part. Besides, am/pm part may locate before the hour/minute part or after the hour/minute part depending on locale. Just like the system display time.
When system is set to use 12-hour format, it's just simple. But when the system is using 24-hour format, I just can't get the localized 12-hour format time string.
Well this should work:
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc]init];
[dateFormatter setDateFormat:[NSDateFormatter dateFormatFromTemplate:#"hh:mm a" options:0 locale:[NSLocale currentLocale]]];
NSString *theTime = [dateFormatter stringFromDate:[NSDate date]];
This should get you a date formatter that will give the date in 12 hour format. The lower case hh indicates hours 1-12 format. See the Unicode Technical Standard #35 section of Date Format Patterns for details on the format string.
Unfortunately iOS will rewrite the format string based on the user's 24-hour format preference setting. I can find no way around that setting using Cocoa's date formatting. Since the 24-hour format will drop the am/pm designation, parsing the resulting string to convert hours greater than 12 will result in ambiguous time strings. Therefore the only remaining options I can see is honoring the users 24-hour preference setting or using other localization code. You can write your own, or maybe find an open source replacement.
Swift 3.0
var dateFormatter = DateFormatter()
dateFormatter.dateFormat = DateFormatter.dateFormat(fromTemplate: "hh:mm a", options: 0, locale: NSLocale.current)
var theTime: String = dateFormatter.string(from: Date())
NSInteger originalHour = hour;
BOOL isPm = YES;
if (hour >= 12) {
if (hour > 12)
hour -= 12;
}
else {
isPm = NO;
}
if (hour == 0)
hour = 12;