Swift: NSDateFormatter dateFromString returns nil

问题:

I found something that could solve my problem in Obj-c, but I'm not able to translate the code, so I'm asking for a Swift solution.

I'm parsing some data from a JSON file and i get an issue retrieving the date; here is the code :

println(data) // "Fri, 16 Jan 2015 11:49:00 +0100"

var dateFormatter           = NSDateFormatter()
dateFormatter.dateFormat    = "EEE, dd LLL yyyy HH:mm:ss ZZZ"
let formattedDate           = dateFormatter.dateFromString(data)

println(formattedDate) // returns 'Optional(2015-01-16 11:49:00 +0100)' if running on an iOs Simulator
                       // returns 'nil' if runnig on an iPhone

Like I write in the code comments, i get correctly the optional type of the date if I run it on an iOs Simulator or in the playground, but i get nil if it is running on an iPhone.

Can anyone help? Thanks in advice..

P.S. Sorry for my bad english

回答1:

For the others who get here and don't read the comments of the initial post ;)

As @rintaro pointed out - and what was my problem too - you have to add a locale when you use fixed-format dates:

If you're working with fixed-format dates, you should first set the locale of the date formatter to something appropriate for your fixed format. In most cases the best locale to choose is en_US_POSIX

https://developer.apple.com/library/content/documentation/Cocoa/Conceptual/DataFormatting/Articles/dfDateFormatting10_4.html#//apple_ref/doc/uid/TP40002369-SW7

So in Swift 3 you would have to add

dateFormatter.locale = Locale(identifier: "en_US_POSIX")