NSDateFormatter在OS 4.0中返回nil [英] NSDateFormatter returning nil in OS 4.0

问题描述

我在OS 3.x上运行了以下代码

I had the following code working on on OS 3.x

NSString *stringDate = @"2010-06-21T20:06:36+00:00";
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:@"yyyy-MM-dd'T'HH:mm:ssZ"];
NSDate *theDate = [dateFormatter dateFromString:stringDate];
NSLog(@"%@",[dateFormatter stringFromDate:theDate]);

但现在在iOS4模拟器下的最新xcode 3.2.3中，变量theDate为零。

but now in the newest xcode 3.2.3 under the iOS4 simulator, the varialble theDate is nil.

我查看了类引用，并没有看到使用这些特定方法对iOS4不同的任何弃用或实现。我遗漏了什么？

I have looked through the class reference and do not see anything deprecated or implemented differently for iOS4 with these specific methods. What did i leave out?

推荐答案

我发现如果你这样做会有效（见下文）。关键是使用方法：
- [NSDateFormatter getObjectValue：forString：range：error：]

I found out it works if you do it this way (see below). The key is using the method: - [NSDateFormatter getObjectValue:forString:range:error:]

而不是

- [NSDateFormatter dateFromString]

完整代码：

+ (NSDate *)parseRFC3339Date:(NSString *)dateString 
{
    NSDateFormatter *rfc3339TimestampFormatterWithTimeZone = [[NSDateFormatter alloc] init];
    [rfc3339TimestampFormatterWithTimeZone setLocale:[[[NSLocale alloc] initWithLocaleIdentifier:@"en_US_POSIX"] autorelease]];
    [rfc3339TimestampFormatterWithTimeZone setDateFormat:@"yyyy-MM-dd'T'HH:mm:ssZ"];

    NSDate *theDate = nil;
    NSError *error = nil; 
    if (![rfc3339TimestampFormatterWithTimeZone getObjectValue:&theDate forString:dateString range:nil error:&error]) {
        NSLog(@"Date '%@' could not be parsed: %@", dateString, error);
    }

    [rfc3339TimestampFormatterWithTimeZone release];
    return theDate;
}

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