Cocoa touch NSDateFormatter为“@”返回零;“年月日”;在iOS 3.0中
我有这部分代码:Cocoa touch NSDateFormatter为“@”返回零;“年月日”;在iOS 3.0中,cocoa-touch,iphone-sdk-3.0,ios4,nsdate,nsdateformatter,Cocoa Touch,Iphone Sdk 3.0,Ios4,Nsdate,Nsdateformatter,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]; [dateForm
NSDate *date =nil;
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateStyle:NSDateFormatterMediumStyle];
[dateFormatter setDateFormat:@"dd-MM-yy"];
date = [dateFormatter dateFromString:inString];
[dateFormatter release];
正如iOS 4.0中所预期的那样,它工作得非常好。但是3.0中没有相同的代码
我得到的字符串类似于“12-Nov-10”,它包含在inString指针中
如果本机操作系统为3.0或3.1,则日期格式化程序返回nil。出于某些原因,我需要坚持相同的日期格式。还有其他人面临过这个问题吗?有没有解决这个问题的建议
谢谢
拉吉
编辑:
在Harkonian提出以下建议和问答讨论后,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];
如果使用用户可见的日期,则应避免设置日期格式字符串,因为很难预测格式字符串在所有可能的用户配置中的表达方式。相反,您应该尝试限制自己设置日期和时间样式(通过-[NSDateFormatter setDateStyle:]和-[NSDateFormatter setTimeStyle:]) 另一方面,如果使用的是固定格式的日期,则应首先将日期格式化程序的区域设置设置为适合固定格式的内容。在大多数情况下,最好选择的语言环境是“en_US_POSIX”,这是一个专门设计的语言环境,无论用户和系统偏好如何,都能产生美国英语的结果。“en_US_POSIX”在时间上也是不变的(如果美国在将来的某个时候改变日期格式,“en_US”将改变以反映新的行为,但“en_US_POSIX”不会),在机器之间(“en_US_POSIX”在iPhone操作系统上的工作方式与在Mac OS X上的工作方式相同,在其他平台上的工作方式也一样) 一旦将“en_US_POSIX”设置为日期格式化程序的区域设置,就可以设置日期格式字符串,并且日期格式化程序将对所有用户保持一致的行为 以上信息和更多信息可以在苹果的 以下是我的应用程序中实现上述建议的代码片段:
static NSDateFormatter* dateFormatter = nil;
if (!dateFormatter) {
dateFormatter = [[NSDateFormatter alloc] init];
NSLocale *enUSPOSIXLocale = [[[NSLocale alloc]
initWithLocaleIdentifier:@"en_US_POSIX"] autorelease];
assert(enUSPOSIXLocale != nil);
[dateFormatter setLocale:enUSPOSIXLocale];
[dateFormatter setTimeZone:[NSTimeZone timeZoneForSecondsFromGMT:0]];
dateFormatter.dateFormat = @"EEE, dd MMM yyyy HH:mm:ss +0000";
}
一个非常有用的页面已经不存在了,因此只需将其内容放在此处存档即可:
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)
谢谢,将格式字符串从“MM”改为“MMM”已经成功了。更重要的是你对地点和指向苹果讨论的指针的解释。我对时区不感兴趣,因为我没有收到任何时区。有关使用日期格式化程序的更多信息: