无法从字符串获取NSDate

Question

I have following date in string formate "date string : 2014-09-28 17:30:00"

Now, I want to convert it into NSDate.

I have use following code for this.

NSString *date = @"2014-09-28 17:30:00";
NSDateFormatter *dateFormatter1 = [[NSDateFormatter alloc] init];
[dateFormatter1 setDateFormat:@"yyyy-MM-dd HH:mm:ss"];

NSDate *dateFromString = [[NSDate alloc] init];
dateFromString = [dateFormatter1 dateFromString:date];
NSLog(@"date from string: %@", dateFromString);

I got the following output.

date from string: 2014-09-28 12:00:00 +0000

So, Here Time is changed.

Please tell me, How can I convert into NSDate. What I am missing here?

Answer 1

When you pass an NSDate object into NSLog , it will print the NSDate in GMT time, which may not be your timezone (and why you were getting 12:00 instead of 17:30), this would also cause the output of your NSLog statement to be different for people who are running your code in different timezones, so what you want to do is call the [NSDateFormatter stringFromDate:] method if you want to keep your specified time from your date object:

So replace this line of code:

// Will print out GMT time by default (+0000)
NSLog(@"date from string: %@", dateFromString);

With this line:

// Will honor the timezone of your original NSDate object:
NSLog(@"date from string: %@", [dateFormatter1 stringFromDate:dateFromString]);

And that should print out the value you were hoping for.

// --------------------------//

Note: It is important to understand that NSDate objects do not have any concept of timezones, so it is up to the developer to manage and track their timezones with the provided platform methods.

On iOS, you can look into using this class:

NSTimeZone , which can help you manage/assign your timezone(s) on iOS platforms.

If you are developing for OSX, you can assign a timezone and locale with this method: -descriptionWithCalendarFormat:timeZone:locale: . (Sadly, this method is OSX-only)

Hope that helps.

Answer 2

There is a time zone component attached to your log at the end that means the date is converted to the specified time zone..here greenwhich mean time

So converting into your time locale can give you the right value you inserted

In your first string add +0000 to the end and check again you can see the value is the same you get.ie the conversion is done on the GMT format

Answer 3

visit https://developer.apple.com/library/mac/documentation/Cocoa/Conceptual/DataFormatting/Articles/dfDateFormatting10_4.html

This documentation provides you how to convert NSString to date.

this code is provided by apple documentation.

    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateStyle:NSDateFormatterMediumStyle];
[dateFormatter setTimeStyle:NSDateFormatterNoStyle];

NSDate *date = [NSDate dateWithTimeIntervalSinceReferenceDate:162000];

NSString *formattedDateString = [dateFormatter stringFromDate:date];
NSLog(@"formattedDateString: %@", formattedDateString);
// Output for locale en_US: "formattedDateString: Jan 2, 2001".

To make string as date

NSString *formattedDateString = [dateFormatter stringFromDate:date];

stringFromDate: Returns a string representation of a given date formatted using the receiver's current settings.

what you had used dateFromString: Returns a date representation of a given string interpreted using the receiver's current settings.