我有一个时间戳字符串,如下:
Thu, 21 May 09 19:10:09 -0700
我想将它转换成类似于“20分钟前”或“3天前”的相对时间戳。
在iPhone上使用Objective-C,最好的方法是什么?
我有一个时间戳字符串,如下:
Thu, 21 May 09 19:10:09 -0700
我想将它转换成类似于“20分钟前”或“3天前”的相对时间戳。
在iPhone上使用Objective-C,最好的方法是什么?
-(NSString *)dateDiff:(NSString *)origDate {
NSDateFormatter *df = [[NSDateFormatter alloc] init];
[df setFormatterBehavior:NSDateFormatterBehavior10_4];
[df setDateFormat:@"EEE, dd MMM yy HH:mm:ss VVVV"];
NSDate *convertedDate = [df dateFromString:origDate];
[df release];
NSDate *todayDate = [NSDate date];
double ti = [convertedDate timeIntervalSinceDate:todayDate];
ti = ti * -1;
if(ti < 1) {
return @"never";
} else if (ti < 60) {
return @"less than a minute ago";
} else if (ti < 3600) {
int diff = round(ti / 60);
return [NSString stringWithFormat:@"%d minutes ago", diff];
} else if (ti < 86400) {
int diff = round(ti / 60 / 60);
return[NSString stringWithFormat:@"%d hours ago", diff];
} else if (ti < 2629743) {
int diff = round(ti / 60 / 60 / 24);
return[NSString stringWithFormat:@"%d days ago", diff];
} else {
return @"never";
}
}
NSDateComponentsFormatter
将为您执行此类转换。 - Tom Harrington以下是Cocoa提供的方法,可以帮助您获取相关信息(不确定它们是否都适用于coca-touch)。
NSDate * today = [NSDate date];
NSLog(@"today: %@", today);
NSString * str = @"Thu, 21 May 09 19:10:09 -0700";
NSDate * past = [NSDate dateWithNaturalLanguageString:str
locale:[[NSUserDefaults
standardUserDefaults] dictionaryRepresentation]];
NSLog(@"str: %@", str);
NSLog(@"past: %@", past);
NSCalendar *gregorian = [[NSCalendar alloc]
initWithCalendarIdentifier:NSGregorianCalendar];
unsigned int unitFlags = NSYearCalendarUnit | NSMonthCalendarUnit |
NSDayCalendarUnit |
NSHourCalendarUnit | NSMinuteCalendarUnit |
NSSecondCalendarUnit;
NSDateComponents *components = [gregorian components:unitFlags
fromDate:past
toDate:today
options:0];
NSLog(@"months: %d", [components month]);
NSLog(@"days: %d", [components day]);
NSLog(@"hours: %d", [components hour]);
NSLog(@"seconds: %d", [components second]);
NSDateComponents对象似乎保存相应单位的差值(如所指定)。 如果您指定了所有的单位,那么可以使用这个方法:
void dump(NSDateComponents * t)
{
if ([t year]) NSLog(@"%d years ago", [t year]);
else if ([t month]) NSLog(@"%d months ago", [t month]);
else if ([t day]) NSLog(@"%d days ago", [t day]);
else if ([t minute]) NSLog(@"%d minutes ago", [t minute]);
else if ([t second]) NSLog(@"%d seconds ago", [t second]);
}
如果您想自行计算,可以查看以下内容:
NSDate timeIntervalSinceDate
然后在算法中使用秒。
免责声明:如果此接口被弃用(我没有检查),苹果推荐的方法是通过NSDateFormatters
,如下面的评论所建议的那样,看起来也很不错 - 我将保留我的答案,出于历史原因,对于某些人来说仍然有用。
NSCalendarDate
已经被弃用,但 NSDateComponents
绝对没有。从 NSDate
获取这些组件的正确方法是使用 NSCalendar
和 NSDateComponents
,如此答案所示。NSDateFormatter
应该用于将日期转换为/从字符串表示形式,而不是获取单个日期组件。 - Nick Forge我还不能编辑,但是我使用了Gilean的代码并进行了一些调整,将其转换为NSDateFormatter的一个类别。
它接受格式字符串,因此可以处理任意字符串,并添加了if语句以使单数事件在语法上正确。
谢谢,
Carl C-M
@interface NSDateFormatter (Extras)
+ (NSString *)dateDifferenceStringFromString:(NSString *)dateString
withFormat:(NSString *)dateFormat;
@end
@implementation NSDateFormatter (Extras)
+ (NSString *)dateDifferenceStringFromString:(NSString *)dateString
withFormat:(NSString *)dateFormat
{
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setFormatterBehavior:NSDateFormatterBehavior10_4];
[dateFormatter setDateFormat:dateFormat];
NSDate *date = [dateFormatter dateFromString:dateString];
[dateFormatter release];
NSDate *now = [NSDate date];
double time = [date timeIntervalSinceDate:now];
time *= -1;
if(time < 1) {
return dateString;
} else if (time < 60) {
return @"less than a minute ago";
} else if (time < 3600) {
int diff = round(time / 60);
if (diff == 1)
return [NSString stringWithFormat:@"1 minute ago", diff];
return [NSString stringWithFormat:@"%d minutes ago", diff];
} else if (time < 86400) {
int diff = round(time / 60 / 60);
if (diff == 1)
return [NSString stringWithFormat:@"1 hour ago", diff];
return [NSString stringWithFormat:@"%d hours ago", diff];
} else if (time < 604800) {
int diff = round(time / 60 / 60 / 24);
if (diff == 1)
return [NSString stringWithFormat:@"yesterday", diff];
if (diff == 7)
return [NSString stringWithFormat:@"last week", diff];
return[NSString stringWithFormat:@"%d days ago", diff];
} else {
int diff = round(time / 60 / 60 / 24 / 7);
if (diff == 1)
return [NSString stringWithFormat:@"last week", diff];
return [NSString stringWithFormat:@"%d weeks ago", diff];
}
}
@end
为了完整起见,基于@Gilean的答案,这里是一个简单的NSDate类别的完整代码,它模拟了rails的漂亮日期助手。关于类别的复习,这些都是您将在NSDate对象上调用的实例方法。因此,如果我有一个表示昨天的NSDate,[myDate distanceOfTimeInWordsToNow] =>“1 day”。
希望对您有所帮助!
@interface NSDate (NSDate_Relativity)
-(NSString *)distanceOfTimeInWordsSinceDate:(NSDate *)aDate;
-(NSString *)distanceOfTimeInWordsToNow;
@end
@implementation NSDate (NSDate_Relativity)
-(NSString *)distanceOfTimeInWordsToNow {
return [self distanceOfTimeInWordsSinceDate:[NSDate date]];
}
-(NSString *)distanceOfTimeInWordsSinceDate:(NSDate *)aDate {
double interval = [self timeIntervalSinceDate:aDate];
NSString *timeUnit;
int timeValue;
if (interval < 0) {
interval = interval * -1;
}
if (interval< 60) {
return @"seconds";
} else if (interval< 3600) { // minutes
timeValue = round(interval / 60);
if (timeValue == 1) {
timeUnit = @"minute";
} else {
timeUnit = @"minutes";
}
} else if (interval< 86400) {
timeValue = round(interval / 60 / 60);
if (timeValue == 1) {
timeUnit = @"hour";
} else {
timeUnit = @"hours";
}
} else if (interval< 2629743) {
int days = round(interval / 60 / 60 / 24);
if (days < 7) {
timeValue = days;
if (timeValue == 1) {
timeUnit = @"day";
} else {
timeUnit = @"days";
}
} else if (days < 30) {
int weeks = days / 7;
timeValue = weeks;
if (timeValue == 1) {
timeUnit = @"week";
} else {
timeUnit = @"weeks";
}
} else if (days < 365) {
int months = days / 30;
timeValue = months;
if (timeValue == 1) {
timeUnit = @"month";
} else {
timeUnit = @"months";
}
} else if (days < 30000) { // this is roughly 82 years. After that, we'll say 'forever'
int years = days / 365;
timeValue = years;
if (timeValue == 1) {
timeUnit = @"year";
} else {
timeUnit = @"years";
}
} else {
return @"forever ago";
}
}
return [NSString stringWithFormat:@"%d %@", timeValue, timeUnit];
}
@end
已经有许多答案提供了相同的解决方案,但是多一些选择也无妨。以下是我想出来的解决方法。
- (NSString *)stringForTimeIntervalSinceCreated:(NSDate *)dateTime
{
NSDictionary *timeScale = @{@"second":@1,
@"minute":@60,
@"hour":@3600,
@"day":@86400,
@"week":@605800,
@"month":@2629743,
@"year":@31556926};
NSString *scale;
int timeAgo = 0-(int)[dateTime timeIntervalSinceNow];
if (timeAgo < 60) {
scale = @"second";
} else if (timeAgo < 3600) {
scale = @"minute";
} else if (timeAgo < 86400) {
scale = @"hour";
} else if (timeAgo < 605800) {
scale = @"day";
} else if (timeAgo < 2629743) {
scale = @"week";
} else if (timeAgo < 31556926) {
scale = @"month";
} else {
scale = @"year";
}
timeAgo = timeAgo/[[timeScale objectForKey:scale] integerValue];
NSString *s = @"";
if (timeAgo > 1) {
s = @"s";
}
return [NSString stringWithFormat:@"%d %@%@ ago", timeAgo, scale, s];
}
@interface NSDate (Extras)
- (NSString *)differenceString;
@end
@implementation NSDate (Extras)
- (NSString *)differenceString{
NSDate* date = self;
NSDate *now = [NSDate date];
double time = [date timeIntervalSinceDate:now];
time *= -1;
if (time < 60) {
int diff = round(time);
if (diff == 1)
return @"1 second ago";
return [NSString stringWithFormat:@"%d seconds ago", diff];
} else if (time < 3600) {
int diff = round(time / 60);
if (diff == 1)
return @"1 minute ago";
return [NSString stringWithFormat:@"%d minutes ago", diff];
} else if (time < 86400) {
int diff = round(time / 60 / 60);
if (diff == 1)
return @"1 hour ago";
return [NSString stringWithFormat:@"%d hours ago", diff];
} else if (time < 604800) {
int diff = round(time / 60 / 60 / 24);
if (diff == 1)
return @"yesterday";
if (diff == 7)
return @"a week ago";
return[NSString stringWithFormat:@"%d days ago", diff];
} else {
int diff = round(time / 60 / 60 / 24 / 7);
if (diff == 1)
return @"a week ago";
return [NSString stringWithFormat:@"%d weeks ago", diff];
}
}
@end
在Swift中
用法:
let time = NSDate(timeIntervalSince1970: timestamp).timeIntervalSinceNow
let relativeTimeString = NSDate.relativeTimeInString(time)
println(relativeTimeString)
扩展:
extension NSDate {
class func relativeTimeInString(value: NSTimeInterval) -> String {
func getTimeData(value: NSTimeInterval) -> (count: Int, suffix: String) {
let count = Int(floor(value))
let suffix = count != 1 ? "s" : ""
return (count: count, suffix: suffix)
}
let value = -value
switch value {
case 0...15: return "just now"
case 0..<60:
let timeData = getTimeData(value)
return "\(timeData.count) second\(timeData.suffix) ago"
case 0..<3600:
let timeData = getTimeData(value/60)
return "\(timeData.count) minute\(timeData.suffix) ago"
case 0..<86400:
let timeData = getTimeData(value/3600)
return "\(timeData.count) hour\(timeData.suffix) ago"
case 0..<604800:
let timeData = getTimeData(value/86400)
return "\(timeData.count) day\(timeData.suffix) ago"
default:
let timeData = getTimeData(value/604800)
return "\(timeData.count) week\(timeData.suffix) ago"
}
}
}
NSDate(timeIntervalSince1970: timestamp).timeIntervalSinceNow * -1
不应该被添加到主函数 relativeTimeInString
中吗?因为现在你总是需要在那之前进行这个计算。 - AntoinetimeIntervalSinceDate
返回时间间隔(秒)。
快速练习,使用Objective-C实现:
然后实现这个伪代码:
if (x < 60) // x seconds ago
else if( x/60 < 60) // floor(x/60) minutes ago
else if (x/(60*60) < 24) // floor(x/(60*60) hours ago
else if (x/(24*60*60) < 7) // floor(x(24*60*60) days ago
等等...
然后你需要决定一个月是30天、31天还是28天。保持简单 - 选择30天。
可能有更好的方法,但现在已经是凌晨2点了,这是我想到的第一件事...
我的解决方案:
- (NSString *) dateToName:(NSDate*)dt withSec:(BOOL)sec {
NSLocale *locale = [NSLocale currentLocale];
NSTimeInterval tI = [[NSDate date] timeIntervalSinceDate:dt];
if (tI < 60) {
if (sec == NO) {
return NSLocalizedString(@"Just Now", @"");
}
return [NSString stringWithFormat:
NSLocalizedString(@"%d seconds ago", @""),(int)tI];
}
if (tI < 3600) {
return [NSString stringWithFormat:
NSLocalizedString(@"%d minutes ago", @""),(int)(tI/60)];
}
if (tI < 86400) {
return [NSString stringWithFormat:
NSLocalizedString(@"%d hours ago", @""),(int)tI/3600];
}
NSDateFormatter *relativeDateFormatter = [[NSDateFormatter alloc] init];
[relativeDateFormatter setTimeStyle:NSDateFormatterNoStyle];
[relativeDateFormatter setDateStyle:NSDateFormatterMediumStyle];
[relativeDateFormatter setDoesRelativeDateFormatting:YES];
[relativeDateFormatter setLocale:locale];
NSString * relativeFormattedString =
[relativeDateFormatter stringForObjectValue:dt];
return relativeFormattedString;
}
不确定为什么这不在cocoa-touch中,一个好的标准方法会很棒。
设置一些类型来保持数据,如果您需要更多本地化,则会使其更容易。(如果需要更多时间段,请扩展)
typedef struct DayHours {
int Days;
double Hours;
} DayHours;
+ (DayHours) getHourBasedTimeInterval:(double) hourBased withHoursPerDay:(double) hpd
{
int NumberOfDays = (int)(fabs(hourBased) / hpd);
float hoursegment = fabs(hourBased) - (NumberOfDays * hpd);
DayHours dh;
dh.Days = NumberOfDays;
dh.Hours = hoursegment;
return dh;
}