NULL value from NSDateFormatter from XML

问题

This was working fine before compiling with iOS4.0 and I can't figure out what's wrong.

Here's the problem. I send my app scores from my database with a date/time on it. My goal is to store that in CoreData. When I use the code below I get a null value for the date.

Code:

     NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
        NSLocale *locale = [[NSLocale alloc] initWithLocaleIdentifier:@"US"];
        [dateFormatter setLocale:locale];
        [dateFormatter setDateFormat:@"MM/dd/yyyy HH:mm:ss ZZZ"];
        currentDownloadedScore.dateEntered = [dateFormatter dateFromString:self.currentValue];
        NSLog(@"Date CV: %@",self.currentValue);
        NSLog(@"Date: %@",[currentDownloadedScore.dateEntered description]);
        [locale release];
        [dateFormatter release];

Here's the result in the debugger:

2010-07-16 08:15:35.741 MyApp[75003:207] Date CV: 07/16/2010 04:21:00 +00:00
2010-07-16 08:15:35.742 MyApp[75003:207] Date: (null)
2010-07-16 08:15:35.745 MyApp[75003:207] Date CV: 07/16/2010 01:09:26 +00:00
2010-07-16 08:15:35.749 MyApp[75003:207] Date: (null)

Any help is appreciated! Thanks.

回答1:

I found the issue. It seems like the ZZZ part of the formating NO LONGER accepts the colon : in the time.

Works: 07/16/2010 04:21:00 +0000

Doesn't work: 07/16/2010 04:21:00 +00:00

To support the current apps that are out, all I did was search for the +00:00 part in the string and replace it with +0000. TADA! It works!

回答2:

NSDateFormatter has gotten very picky in iOS4. This other SO question had the same problem and has a couple different solutions.

回答3:

I had the same problem. For me, the problem was that I had a line break in my XML feed for the date, so this code fixed it for me:

[currentDate replaceOccurrencesOfString:@"\n" withString:@"" options:NSCaseInsensitiveSearch range:NSMakeRange(0,[currentDate length])];

来源：https://stackoverflow.com/questions/3264729/null-value-from-nsdateformatter-from-xml