nsdate

Will two [NSDate date] following each-other always return different times?

由 落爺英雄遲暮 提交于 2019-12-04 04:43:03
问题 Will dateA and dateB always be different? // Two [NSDate date] following each other NSDate *dateA = [NSDate date]; // Line X NSDate *dateB = [NSDate date]; // Line X+1 That is, will the line below always return NO? [dateA isEqualToDate:dateB] ("Always" meaning that like a very fast processor wouldn't execute the two commands so fast that dateA and dateB would be assigned the same time with "sub-second" accuracy). I want to have a "unique" timestamp for some internal identification (not DB

NSDate change time zone

由 社会主义新天地 提交于 2019-12-04 03:58:36
问题 I am writing an app that involves time zone. I want to grab the user's device time, lets call that dateA , and I have a target date that will always be in EDT time zone ( dateB ). I want to get the difference between the 2 dates and show the user, but in dateB 's time zone. eg: user device time is 07:30AM PDT, and dateB is 11:00AM EDT. So the time difference would be 30 minutes. My algorithm is: 1) Get user device time 2) convert to EDT 3) grab the time difference between dateA and dateB My

Determine the number of months between two dates using Cocoa

由 一世执手 提交于 2019-12-04 03:36:47
How do I calculate the number of months between two dates using Cocoa? Thanks, Stan Look at NSCalendars components:fromDate:toDate:options method. It allows you to subtract dates and then extract the months property value NSInteger month = [[[NSCalendar currentCalendar] components: NSCalendarUnitMonth fromDate: yourFirstDate toDate: yourSecondDate options: 0] month]; To get an answer that includes the fraction of a month the following can be used: - (NSNumber *)numberOfMonthsBetweenFirstDate:(NSDate *)firstDate secondDate:(NSDate *)secondDate { if ([firstDate compare:secondDate] ==

How to retrieve number of hours past midnight from an NSDate object?

由 爷，独闯天下 提交于 2019-12-04 03:34:20
问题 I need to retrieve the number of hours past midnight from a UIDatePicker control in an iPhone project. datePickerMode is set to UIDatePickerModeTime , so the user only can set a time, no date. When the user is done and dismisses the view the UIDatePicker is on, the following date might be retrieved (as an example): NSDate *returnTime = timePicker.date; NSLog(@"returnTime: %@", returnTime); // returns for example @"1970-01-01 10:13:00 PM +0000" As said, I'm looking for the number of hours past

How to add a number of weeks to an NSDate?

由 ⅰ亾dé卋堺 提交于 2019-12-04 03:11:03
问题 I have in the past used the below function to add on a specific time interval using NSDateComponents to an existing date. (NSDate *)dateByAddingComponents:(NSDateComponents *)comps toDate:(NSDate *)date options:(NSCalendarOptions)opts From iOS8 the week value is deprecated for NSDateComponents , which means I can't achieve what I want to do: generate a new NSDate by adding a certain number of weeks to a given NSDate . Any help would be greatly appreciated. 回答1: Update: As Zaph said in his

NSDate from Swift 2.3 to Date from Swift 3 Conversion

由 。_饼干妹妹 提交于 2019-12-04 02:58:45
So I've just updated to Xcode 8 and converted my Swift 2.3 code to Swift 3, and Swift 3 just converted all NSDate to Foundation.Date And I had an extension for NSDate , now called Foundation.Date , it looked like this: extension NSDate { var firstDayOfTheMonth:NSDate { var date: NSDate? NSCalendar.currentCalendar().rangeOfUnit(.Month, startDate:&date , interval: nil, forDate: self) return date! } } And Swift 3 converted it to this: extension Foundation.Date { var firstDayOfTheMonth:Foundation.Date { var date: Foundation.Date? (Calendar.current as NSCalendar).range(of: .month, start:&date ,

Date formatter returns nil for June

由 非 Y 不嫁゛ 提交于 2019-12-04 02:53:32
I have a strange problem with those lines of code : NSDateFormatter * df = [[NSDateFormatter alloc] init]; [df setDateFormat:@"MMyyyy"]; NSDate * date = [df dateFromString:@"062008"]; NSLog(@"Date %@", date); The result is : Date (null) But when I change the month like this : NSDateFormatter * df = [[NSDateFormatter alloc] init]; [df setDateFormat:@"MMyyyy"]; NSDate * date = [df dateFromString:@"072008"]; NSLog(@"Date %@", date); The result is : Date 2008-06-30 23:00:00 +0000 For only the month of June (06), the date conversion from string fails ! I think, it's something related to timezone,

Copying an NSDate (wanting independent objects)

由 ╄→гoц情女王★ 提交于 2019-12-04 02:46:46
NSDate conforms to NSCopying protocol. According to the documentation for NSCopying protocol: a copy must be a functionally independent object with values identical to the original at the time the copy was made. But, when I do this: NSDate *date1 = [NSDate date]; NSDate *date2 = [date1 copy]; NSLog(@"result: date1 0x%x date2 0x%x", (int)date1, (int)date2); // "result: date1 0x2facb0 date2 0x2facb0" The two objects are identical (same object id). What am I missing? How do I get an independent object as a copy? copy does not guarantee different object pointer. “Functionally independent” means

How do I implement previous/next month buttons and show dates for current month?

由 耗尽温柔 提交于 2019-12-04 02:35:34
问题 Scenario: I have an expense tracking iOS Application and I am storing expenses from a expense detail view controller into a table view (with fetched results controller) that shows the list of expenses along with the category and amount and date. I do have a date attribute in my entity "Money" which is a parent entity for either an expense or an income. Question: What I want is to basically categorize my expenses on a monthly basis and display it as the section header title for example : (Nov

NSDateFormatter for BST instead of GMT+1

由 ╄→尐↘猪︶ㄣ 提交于 2019-12-04 02:29:55
问题 I want to display the following string on my time axis: "GMT/BST" Here's the code: NSDateFormatter *dateformatter=[[NSDateFormatter alloc] init]; [dateformatter setDateFormat:@"zzz"]; timeZoneString = [NSMutableString stringWithFormat:@"%@ / %@",[dateformatter stringFromDate:startDate],[dateformatter stringFromDate:endDate]]; But this gives "GMT/GMT+01:00" What is the NSDateFormatter code to turn "GMT+01:00" into "BST" ? I can't get the right formatters to do this, having tried z|zzz|Z|ZZZ|v
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