NSDate 的时间/日期显示就像 iOS 中的消息和邮件应用程序一样

Question

我正在构建一个应用程序，如果对象是在 24 小时之前创建的，则需要我显示时间和日期，例如星期日等。就像 iOS 中的消息和邮件应用程序会显示 24 小时的时间，而不是将其更改为显示日期'星期一，星期二..'。我正在寻找是否可以找到任何与此完全相同的框架，还是我必须为此编写代码？

Answer 1

以下是使用 Swift 4 和 5 本地完成所有操作的方法：

extension Date {

    func formatRelativeString() -> String {
        let dateFormatter = DateFormatter()
        let calendar = Calendar(identifier: .gregorian)
        dateFormatter.doesRelativeDateFormatting = true

        if calendar.isDateInToday(self) {
            dateFormatter.timeStyle = .short
            dateFormatter.dateStyle = .none
        } else if calendar.isDateInYesterday(self){
            dateFormatter.timeStyle = .none
            dateFormatter.dateStyle = .medium
        } else if calendar.compare(Date(), to: self, toGranularity: .weekOfYear) == .orderedSame {
            let weekday = calendar.dateComponents([.weekday], from: self).weekday ?? 0
            return dateFormatter.weekdaySymbols[weekday-1]
        } else {
            dateFormatter.timeStyle = .none
            dateFormatter.dateStyle = .short
        }

        return dateFormatter.string(from: self)
    }
}

Answer 2

我也需要这个，所以我写了以下 NSDate 扩展：

extension NSDate {

    func formattedRelativeString() -> String {
        let dateFormatter = NSDateFormatter()
        dateFormatter.doesRelativeDateFormatting = true

        if isToday() {
            dateFormatter.timeStyle = .ShortStyle
            dateFormatter.dateStyle = .NoStyle
        } else if isYesterday() {
            dateFormatter.timeStyle = .NoStyle
            dateFormatter.dateStyle = .MediumStyle
        } else if daysAgo() < 6 {
            return dateFormatter.weekdaySymbols[weekday()-1]
        } else {
            dateFormatter.timeStyle = .NoStyle
            dateFormatter.dateStyle = .ShortStyle
        }

        return dateFormatter.stringFromDate(self)
    }
}

这需要 Matthew York 出色的 DateTools 才能发挥作用。

Answer 3

Swift 3 版本的@avf 回复：

extension NSDate {
    func formattedRelativeString() -> String 
    {
        let dateFormatter = DateFormatter()
        dateFormatter.doesRelativeDateFormatting = true

        if isToday() {
            dateFormatter.timeStyle = .short
            dateFormatter.dateStyle = .none
        } else if isYesterday() {
            dateFormatter.timeStyle = .none
            dateFormatter.dateStyle = .medium
        } else if daysAgo() < 6 {
            return dateFormatter.weekdaySymbols[weekday()-1]
        } else {
            dateFormatter.timeStyle = .none
            dateFormatter.dateStyle = .short
        }

        return dateFormatter.string(from: self as Date)
    }
}

Answer 4

为 swift 4 更新：

 extension NSDate {

    func formattedRelativeString() -> String 
    {
        let dateFormatter = DateFormatter()

        if isInToday || isInYesterday {
            /// today and yesterday
            /// Today, 3:57 PM
            dateFormatter.doesRelativeDateFormatting = true
            dateFormatter.timeStyle = .short
            dateFormatter.dateStyle = .short
        } else if isLessThanAweekAgo {

            /// less than a week ago
            /// Friday, 4:03 PM
            dateFormatter.dateFormat = "EEEE, h:mm a"
         } else if isInThisYear {

            // more than a week ago
            // Fri, 4 Aug, 3:55
            dateFormatter.dateFormat = "E, d MMM, h:mm a"
         } else {
            // more than a year ago
            // Aug 10, 2016, 3:56
            dateFormatter.dateFormat = "MMM d, yyyy, h:mm a"
         }

        return dateFormatter.string(from: self)
    }

}

您可以使用这些示例日期在操场上对其进行测试：

let now = Date()
let yesterday = Date(timeInterval: -24*60*60, since: Date())
let weekAgo = Date(timeInterval: -7*24*60*60, since: Date())
let yearAgo = Date(timeInterval: -366*24*60*60, since: Date())

Answer 5

NSString *dateString = [NSDateFormatter localizedStringFromDate:[NSDate date]
                                                              dateStyle:NSDateFormatterShortStyle
                                                              timeStyle:NSDateFormatterFullStyle];
        NSLog(@"%@",dateString);

试试这个代码，根据你的要求修改它。

Answer 6

Objective C 格式化日期和时间。

使用 Matthew York 出色的 DateTools 方法。

NSDate 扩展：

-(NSString *)formatDateTimeToString{
    NSDateFormatter* dateFormatter = [[NSDateFormatter alloc]init];
    [dateFormatter setLocale: [[NSLocale alloc] initWithLocaleIdentifier: [[NSLocale currentLocale] localeIdentifier]]];

    if ([[NSCalendar currentCalendar] isDateInToday:self])
    {
        [dateFormatter setTimeStyle:NSDateFormatterShortStyle];
        [dateFormatter setDateStyle:NSDateFormatterNoStyle];
    }
    else if ([[NSCalendar currentCalendar] isDateInYesterday:self])
    {
        [dateFormatter setDoesRelativeDateFormatting:YES];
        [dateFormatter setTimeStyle:NSDateFormatterNoStyle];
        [dateFormatter setDateStyle:NSDateFormatterMediumStyle];
    }
    else if ([self daysAgo]<6)
    {
        [dateFormatter setDateFormat:@"EEEE"];
    }
    else
    {
        [dateFormatter setTimeStyle:NSDateFormatterNoStyle];
        [dateFormatter setDateStyle:NSDateFormatterShortStyle];
    }
    return  [dateFormatter stringFromDate:self];
}


-(NSInteger)daysAgo{
    return [self daysEarlierThan:[NSDate date]];
}

-(NSInteger)daysEarlierThan:(NSDate *)date{
    return ABS(MIN([self daysFrom:date], 0));
}
-(NSInteger)daysFrom:(NSDate *)date{
    return [self daysFrom:date calendar:nil];
}
-(NSInteger)daysFrom:(NSDate *)date calendar:(NSCalendar *)calendar{
    NSDate *earliest = [self earlierDate:date];
    NSDate *latest = (earliest == self) ? date : self;
    NSInteger multiplier = (earliest == self) ? -1 : 1;
    NSDateComponents *components = [[NSCalendar currentCalendar] components:NSCalendarUnitDay fromDate:earliest toDate:latest options:0];
    return multiplier*components.day;
}

Answer 7

使用 NSDateFormatter 并将其 doesRelativeDateFormatting 属性设置为 YES。