I'm trying to debug code that makes pretty heavy use of dates which has me comparing tons of different NSDate values in the debugger. The debugger is displaying those dates in UTC format--for example:
date1 = (NSDate *) 0x01b11460 #"2012-02-15 18:55:00 +0000"
It would be a lot easier for me if it would show them in my local timezone as that is what the test code I'm debugging seems to be using.
I do have feeling that I'm missing something much more basic here so I'm hoping someone can enlighten me. Thanks in advance.
While a little "hackish" you can create a subclass of NSDate and override just the
-(NSString *)description;
method to return a date formatted however you want.
The debugger isn't doing any special decoding for you, it's just calling the "description" method of the object it wants to display. A handy trick... (Which is why all my objects publish a concise description suitable for viewing in a debugger.)
In the end, what worked best was in fact adding a Category for NSDate that just overrides the description method to return a string that represents the NSDate in my current timezone. I also made it DEBUG only as I really just need this override in place when debugging.
Here's the .h file I used:
#ifdef DEBUG
#interface NSDate (DebugHelper)
-(NSString *)description;
#end
#endif
and the .m file:
#ifdef DEBUG
#import "NSDate+DebugHelper.h"
#implementation NSDate (DebugHelper)
-(NSString *) description
{
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setTimeZone:[NSTimeZone systemTimeZone]];
[dateFormatter setTimeStyle:NSDateFormatterShortStyle];
[dateFormatter setDateStyle:NSDateFormatterShortStyle];
return [dateFormatter stringFromDate:self];
}
#end
#endif
Thanks to Jim Hayes and jrturton for the discussion and ideas that led to this answer.
Just did the same thing, however instead of systemTimeZone I used localTimeZone (see the docs as to why it is slightly better). Also I noticed you are alloc'ing the dateFormatter object but never releasing it which is a leak.
Here's my category method:
-(NSString *) description;
{
NSDateFormatter *dateFormatter = [[[NSDateFormatter alloc] init]autorelease];
NSLocale *enUSPOSIXLocale = [[[NSLocale alloc] initWithLocaleIdentifier:#"en_US_POSIX"] autorelease];
[dateFormatter setLocale:enUSPOSIXLocale];
[dateFormatter setTimeZone:[NSTimeZone localTimeZone]];
[dateFormatter setDateStyle:NSDateFormatterLongStyle];
[dateFormatter setTimeStyle:NSDateFormatterLongStyle];
NSString *dateString = [dateFormatter stringFromDate:self];
return dateString;
}
Related
I am new to objective-C and I am trying to insert NSdate but I don't know which library to include in order to call it. I tried the following but without success. Thanks for your help
#import <Cocoa/Cocoa.h>
#import <Foundation/Foundation.h>
#include <CoreFoundation/CoreFoundation.h>
// Get current datetime
NSDate *currentDateTime = [NSDate date];
// Instantiate a NSDateFormatter
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
// Set the dateFormatter format
[dateFormatter setDateFormat:#"yyyy-MM-dd HH:mm:ss"];
// Get the date time in NSString
NSString *dateInString = [dateFormatter stringFromDate:currentDateTime];
// Release the dateFormatter
[dateFormatter release];
You have included every necessary header and you added every necessary framework (all you need for NS* classes is Foundation). The problem is that your statements don't have a scope. Wrap them, for example, in the main() function.
Im working on iphone app using xcode,objective c and targeting ios 5 minimum.
All I am trying to do is convert a string to a date. I have read lots on this and it should be a simple straight forward task. I have seen many other questions like this in forum but what is working for people doesnt seem to be working for me.
Here is what I am doing
NSDateFormatter* dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:#"yyyy-MM-dd"];
NSString *dobText = [dict valueForKey:#"DateOfBirth"];
NSDate *dobDate = [dateFormatter dateFromString:dobText];
the dobText is always in format #"1999-01-01" which matches the date format set in the date formatter but the result when using date from string is always nil.
can anyone explain this to me and let me know how to fix it?
Look at the user preferences on your device. The documentation says:
Note that although setting a format string (setDateFormat:) in
principle specifies an exact format, in practice it may nevertheless
also be overridden by a user’s preferences—see Data Formatting Guide
for more details.
are you sure the date is using a - and not a – in the data you get from the dict. As i can reproduce a nil result when i use a – (alt + -)
NSDateFormatter* dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:#"yyyy-MM-dd"];
NSString *dobText = #"2009-02-12";
NSDate *dobDate = [dateFormatter dateFromString:dobText];
NSLog(#"%#", dobDate);
Try doing this, will likely fix your problem.
NSString *dobText = [[dict valueForKey:#"DateOfBirth"] stringByReplacingOccurrencesOfString:#"—" withString:#"-"];
I suspect like bigkm say, your dashes may be getting in the way.
I would suggest you try a dummy string in line first. e.g.
NSDateFormatter* dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:#"yyyy-MM-dd"];
NSString *dobText = #"1999-01-01" // [dict valueForKey:#"DateOfBirth"];
NSDate *dobDate = [dateFormatter dateFromString:dobText];
Now does that work? It should. Now triangulate another way:
Remove the dashes completely from the dob text, so that it has the format 'yyyyMMdd'
Have the date formatter look for this same format
Does that work? It should. And that would prove that the separator characters in your format are the issue and need some further inspection (or cleansing as bigkm suggested).
Side node re threading: NSDateFormatter is fine if you use it on the thread on which it was created. If you don't, you'll know b/c the app will crash.
If your date format is correct, I can suggest to set NSLocale to your NSDateFormatter.
For me this code works on simulator:
NSString *format = [NSString stringWithFormat:#"EEE, dd MMM yyyy HH:mm:ss Z"];
NSDateFormatter *df = [NSDateFormatter new];
[df setDateFormat:format];
NSDate *date = [df dateFromString:pubDateSttring];
but on the device date is always NIL.
I've found workaround of setting NSLocale:
df.locale = [[NSLocale alloc] initWithLocaleIdentifier:#"en_US_POSIX"];
I have a function that returns an array to hold date info.
- (NSArray*) getTodayArray
{
NSDate *today = [NSDate date];
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:#"YYYY"];
NSString *year = [dateFormatter stringFromDate:today];
[dateFormatter setDateFormat:#"MM"];
NSString *month = [dateFormatter stringFromDate:today];
[dateFormatter release];
NSArray *res = [NSArray arrayWithObjects: year, month, nil];
return res;
}
Q1 : Is there any easy way to get all the info (year, month, date, hour, minute ...) in an array not using setDateFormat over and over again?
Q2 : Is there a way so that I can access the content of array using res['year'] or similar? I mean using dictionary?
Q3 : Do I need to release NSArray *res in the caller of this function?
A1: You can do smth like this:
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:#"YYYY|MM"];
NSArray* d_arr = [[dateFormatter stringFromDate: [NSDate date]] componentsSeparatedByString: #"|"];
A2: Use NSDictionary:
[NSDictionary dictionaryWithObjectsAndKeys: [d_arr objectAtIndex: 0], #"year", [d_arr objectAtIndex: 1], #"month", nil]
A3: return value is autoreleased. you don't need to release it.
#prosseek
1 - I dont think you have another choice to get the year, month, date, hour, minute ... from NSDate other than this.(I am not sure about it though.)
2 - you can access the objects in the dictionary in the above format but something more like objective-c style. like this
[dateDictionary obectForKey:#"year"];
but you need to define the dictionary in that format
like this
NSDictionary *dateDictionary = [NSDictionary dictionaryWithObjects:year,min,hr,nil forKeys:#"year", #"min", #"hour", nil];
3 - no you dont need to release or autorelease the NSArray in the above method . but i think you need to retain it in the array that is receiving res array if you want to use it after a while.
Why don't you just use a NSArray of NSDates?
You can probably get all of your desired functionality out of its plethora of functions.
A1: You could dump it all out into a string, but then you'd have to parse the string, which wouldn't be any easier.
A2: You could do that if you used an NSDictionary instead of an NSArray.*
A3: No, it's already autoreleased.
* Why don't you write a category for NSDate instead?
NSDate+Convenience.h
#interface NSDate (Convenience)
- (NSInteger)year;
- (NSInteger)month;
#end
NSDate+Convenience.m
#implementation NSDate (Convenience)
- (NSInteger)year {
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:#"YYYY"];
NSString *myYear = [dateFormatter stringFromDate:self];
[dateFormatter release];
return myYear;
}
- (NSInteger)month {
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:#"MM"];
NSString *myMonth = [dateFormatter stringFromDate:self];
[dateFormatter release];
return myMonth;
}
#end
Just #include NSDate+Convenience.h wherever you want to use your handy date and month accessors. All of your NSDate instances will then get them:
NSDate *myDate = [NSDate date];
NSLog(#"%ld %ld", [myDate year], [myDate month]);
No need for loosely-typed NSArrays or NSDictionaries to store this stuff.
(Note you could modify the above code to use a shared NSDateFormatter.)
Q1: Not an array, but you can use -[NSCalendar components:fromDate:] to get an NSDateComponents object. You can use it directly or build an array from it, if that is your preference.
Q2: No, but if you return an NSDateComponents object, then you can use -year, -month, etc methods on it.
Q3: No, you don't need to release it in this method or the caller, unless the caller retains it (which may be desirable).
You're looking for the NSDateComponents class. You'll need to create an NSCalendar object first, then call the components:fromDate: method to get the DateComponents object, after which you can access the object's month, year etc. properties.
Not quite sure what you want here. As it stands, the array cannot be accessed in the manner you describe, though if you want you could always create a dictionary and assign values for keys such as 'month' or 'year'. However, it might just be easier to return the DateComponents object, and access its properties.
No, there is no need to release the NSArray. You constructed it using the NSArray class method, which is already autoreleased.
Ive been racking my brains with no luck. Could someone please tell me how i would convert this string:
"2011-01-13T17:00:00+11:00"
into a NSDate?
The unicode date format doc is here
Also, for your situation, you could try this:
// original string
NSString *str = [NSString stringWithFormat:#"2011-01-13T17:00:00+11:00"];
// convert to date
NSDateFormatter *dateFormat = [[NSDateFormatter alloc] init];
// ignore +11 and use timezone name instead of seconds from gmt
[dateFormat setDateFormat:#"YYYY-MM-dd'T'HH:mm:ss'+11:00'"];
[dateFormat setTimeZone:[NSTimeZone timeZoneWithName:#"Australia/Melbourne"]];
NSDate *dte = [dateFormat dateFromString:str];
NSLog(#"Date: %#", dte);
// back to string
NSDateFormatter *dateFormat2 = [[NSDateFormatter alloc] init];
[dateFormat2 setDateFormat:#"YYYY-MM-dd'T'HH:mm:ssZZZ"];
[dateFormat2 setTimeZone:[NSTimeZone timeZoneWithName:#"Australia/Melbourne"]];
NSString *dateString = [dateFormat2 stringFromDate:dte];
NSLog(#"DateString: %#", dateString);
[dateFormat release];
[dateFormat2 release];
Hope this helps.
put the T part in single quotes, and check the unicode docs for the exact formatting. In my case, I have something similar, which I do this:
NSDateFormatter *dateFormat = [[NSDateFormatter alloc] init];
[dateFormat setDateFormat:#"YYYY-MM-dd'T'HH:mm:ss.SSS"];
Again, not exactly the same, but you get the idea. Also, be careful of the timezones when converting back and forth between strings and nsdates.
Again, in my case, I use:
[dateFormat setTimeZone:[NSTimeZone timeZoneWithName:#"America/New_York"]];
Did you try this
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
NSDate *dateT = [dateFormatter dateFromString:str];
Cheers
You might check out TouchTime.
https://github.com/jheising/TouchTime.
It's a direct port of the awesome strtotime function in PHP in 5.4 for Cocoa and iOS. It will take in pretty much any arbitrary format of date or time string and convert it to an NSDate.
Hope it works, and enjoy!
Try using this cocoapods enabled project. There are many added functions that will probably be needed as well.
"A category to extend Cocoa's NSDate class with some convenience functions."
https://github.com/billymeltdown/nsdate-helper
Here's an example from their page:
NSDate *date = [NSDate dateFromString:#"2009-03-01 12:15:23"];
Hey, I've been wokring through my app and removing the memory leaks but the below one has me beaten, any help would be much appreciated.
NSDateFormatter* dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setFormatterBehavior:NSDateFormatterBehavior10_4];
[dateFormatter setDateFormat:#"dd/MM/yyyy"];
claim.date = [dateFormatter dateFromString:[data objectForKey:key]];
[dateFormatter release];
The date property is defined as:
#property (nonatomic, retain) NSDate *date
Thanks
Edit:
Forgot to mention where the memory leak occurred, its on line claim.date = [dateFormatter dateFromString:[data objectForKey:key]];
I suspect one or both of the following:
The owner of claim never released it
The implementation of claim does not send the release message to date in its dealloc and/or does not self.date = nil in the viewDidUnload.