cocoa-touch - 在 iOS 3.0 中，NSDateFormatter 对于 @"dd-MM-yy"返回 nil

Question

我有这部分代码:

NSDate *date =nil;
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateStyle:NSDateFormatterMediumStyle];
[dateFormatter setDateFormat:@"dd-MM-yy"];
date = [dateFormatter dateFromString:inString];
[dateFormatter release];

它工作得很好，正如 iOS 4.0 中所期望的那样。但同样的代码在 3.0 中却没有。

我得到的字符串类似于“12-Nov-10”，它包含在 inString 指针中。

如果 native 操作系统是 3.0 或 3.1，日期格式化程序将返回 nil。由于某些原因，我需要坚持相同的日期格式。还有其他人遇到过这个问题吗？有什么建议可以解决这个问题吗？

谢谢

拉杰

编辑:在 Harkonian 和问答讨论指出以下建议后，正确的代码:

NSDate *date =nil;
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateStyle:NSDateFormatterMediumStyle];
[dateFormatter setDateFormat:@"dd-MMM-yy"];

NSLocale *enUSPOSIXLocale = [[NSLocale alloc] initWithLocaleIdentifier:@"en_US_POSIX"];
[dateFormatter setLocale:enUSPOSIXLocale];
[enUSPOSIXLocale release];

date = [dateFormatter dateFromString:inString];
[dateFormatter release];

Answer 1

一个非常有用的页面不再存在，因此只需将其内容放在这里以供存档:

a:  AM/PM
A:  0~86399999 (Millisecond of Day)

c/cc:   1~7 (Day of Week)
ccc:    Sun/Mon/Tue/Wed/Thu/Fri/Sat
cccc:   Sunday/Monday/Tuesday/Wednesday/Thursday/Friday/Saturday

d:  1~31 (0 padded Day of Month)
D:  1~366 (0 padded Day of Year)

e:  1~7 (0 padded Day of Week)
E~EEE:  Sun/Mon/Tue/Wed/Thu/Fri/Sat
EEEE:   Sunday/Monday/Tuesday/Wednesday/Thursday/Friday/Saturday

F:  1~5 (0 padded Week of Month, first day of week = Monday)

g:  Julian Day Number (number of days since 4713 BC January 1)
G~GGG:  BC/AD (Era Designator Abbreviated)
GGGG:   Before Christ/Anno Domini

h:  1~12 (0 padded Hour (12hr))
H:  0~23 (0 padded Hour (24hr))

k:  1~24 (0 padded Hour (24hr)
K:  0~11 (0 padded Hour (12hr))

L/LL:   1~12 (0 padded Month)
LLL:    Jan/Feb/Mar/Apr/May/Jun/Jul/Aug/Sep/Oct/Nov/Dec
LLLL:   January/February/March/April/May/June/July/August/September/October/November/December

m:  0~59 (0 padded Minute)
M/MM:   1~12 (0 padded Month)
MMM:    Jan/Feb/Mar/Apr/May/Jun/Jul/Aug/Sep/Oct/Nov/Dec
MMMM:   January/February/March/April/May/June/July/August/September/October/November/December

q/qq:   1~4 (0 padded Quarter)
qqq:    Q1/Q2/Q3/Q4
qqqq:   1st quarter/2nd quarter/3rd quarter/4th quarter
Q/QQ:   1~4 (0 padded Quarter)
QQQ:    Q1/Q2/Q3/Q4
QQQQ:   1st quarter/2nd quarter/3rd quarter/4th quarter

s:  0~59 (0 padded Second)
S:  (rounded Sub-Second)

u:  (0 padded Year)

v~vvv:  (General GMT Timezone Abbreviation)
vvvv:   (General GMT Timezone Name)

w:  1~53 (0 padded Week of Year, 1st day of week = Sunday, NB: 1st week of year starts from the last Sunday of last year)
W:  1~5 (0 padded Week of Month, 1st day of week = Sunday)

y/yyyy: (Full Year)
yy/yyy: (2 Digits Year)
Y/YYYY: (Full Year, starting from the Sunday of the 1st week of year)
YY/YYY: (2 Digits Year, starting from the Sunday of the 1st week of year)

z~zzz:  (Specific GMT Timezone Abbreviation)
zzzz:   (Specific GMT Timezone Name)
Z:  +0000 (RFC 822 Timezone)