ios - 如何在 IOS 中将日期格式化为字符串，如 "One Days Ago","Minutes Ago"？

Question

我创建了一个包含 JSON 解析数据的应用程序，这里是我的 JSON 解析数据，其中包含类似“2014-12-02 08:00:42”的日期，然后我将此日期转换为以下格式“2014 年 2 月 12 日”，如下所示

NSDateFormatter * dateFormatter = [[NSDateFormatter alloc]init];
[dateFormatter setDateFormat:@"yyyy-MM-dd hh:mm:ss"];
NSString *date=[dict valueForKey:@"post_date"];
NSDate * dateNotFormatted = [dateFormatter dateFromString:date];
[dateFormatter setDateFormat:@"d MMM YYYY"];
NSString * dateFormatted = [dateFormatter stringFromDate:dateNotFormatted];
cell.timeLabel.text=[dateFormatted uppercaseString];

它工作正常，但现在我想将此 dateFormatted 字符串转换为“一天前”、“分钟前”。我知道这个问题以前被问过很多次。

Answer 1

从 iOS 8 开始，您可以通过使用 NSDateComponentsFormatter 获得很多帮助(包括本地化)。注意:如果您想返回类似“2 天、3 小时、5 分钟前”的字符串，您可以通过更改组件格式化程序上的 allowedUnits 轻松更改字符串显示的粒度。

swift 4:

func timeAgoStringFromDate(date: Date) -> String? {
    let formatter = DateComponentsFormatter()
    formatter.unitsStyle = .full

    let now = Date()

    let calendar = NSCalendar.current
    let components1: Set<Calendar.Component> = [.year, .month, .weekOfMonth, .day, .hour, .minute, .second]
    let components = calendar.dateComponents(components1, from: date, to: now)

    if components.year ?? 0 > 0 {
        formatter.allowedUnits = .year
    } else if components.month ?? 0 > 0 {
        formatter.allowedUnits = .month
    } else if components.weekOfMonth ?? 0 > 0 {
        formatter.allowedUnits = .weekOfMonth
    } else if components.day ?? 0 > 0 {
        formatter.allowedUnits = .day
    } else if components.hour ?? 0 > 0 {
        formatter.allowedUnits = [.hour]
    } else if components.minute ?? 0 > 0 {
        formatter.allowedUnits = .minute
    } else {
        formatter.allowedUnits = .second
    }

    let formatString = NSLocalizedString("%@ left", comment: "Used to say how much time has passed. e.g. '2 hours ago'")

    guard let timeString = formatter.string(for: components) else {
        return nil
    }
    return String(format: formatString, timeString)
}

let str = timeAgoStringFromDate(date: Date().addingTimeInterval(-11000))
// Result: "3 hours, 3 minutes left"

swift :

class func timeAgoStringFromDate(date: NSDate) -> NSString? {
    let formatter = NSDateComponentsFormatter()
    formatter.unitsStyle = .Full

    let now = NSDate()

    let calendar = NSCalendar.currentCalendar()
    let components = calendar.components([NSCalendarUnit.Year, .Month, .WeekOfMonth, .Day, .Hour, .Minute, .Second],
        fromDate: date,
        toDate: now,
        options:NSCalendarOptions(rawValue: 0))

    if components.year > 0 {
        formatter.allowedUnits = .Year
    } else if components.month > 0 {
        formatter.allowedUnits = .Month
    } else if components.weekOfMonth > 0 {
        formatter.allowedUnits = .WeekOfMonth
    } else if components.day > 0 {
        formatter.allowedUnits = .Day
    } else if components.hour > 0 {
        formatter.allowedUnits = .Hour
    } else if components.minute > 0 {
        formatter.allowedUnits = .Minute
    } else {
        formatter.allowedUnits = .Second
    }

    let formatString = NSLocalizedString("%@ ago", comment: "Used to say how much time has passed. e.g. '2 hours ago'")

    guard let timeString = formatter.stringFromDateComponents(components) else {
        return nil
    }
    return String(format: formatString, timeString)
}

objective-C :

+ (NSString *)timeAgoStringFromDate:(NSDate *)date {
    NSDateComponentsFormatter *formatter = [[NSDateComponentsFormatter alloc] init];
    formatter.unitsStyle = NSDateComponentsFormatterUnitsStyleFull;

    NSDate *now = [NSDate date];

    NSCalendar *calendar = [NSCalendar currentCalendar];
    NSDateComponents *components = [calendar components:(NSCalendarUnitYear|NSCalendarUnitMonth|NSCalendarUnitWeekOfMonth|NSCalendarUnitDay|NSCalendarUnitHour|NSCalendarUnitMinute|NSCalendarUnitSecond)
                                               fromDate:date
                                                 toDate:now
                                                options:0];

    if (components.year > 0) {
        formatter.allowedUnits = NSCalendarUnitYear;
    } else if (components.month > 0) {
        formatter.allowedUnits = NSCalendarUnitMonth;
    } else if (components.weekOfMonth > 0) {
        formatter.allowedUnits = NSCalendarUnitWeekOfMonth;
    } else if (components.day > 0) {
        formatter.allowedUnits = NSCalendarUnitDay;
    } else if (components.hour > 0) {
        formatter.allowedUnits = NSCalendarUnitHour;
    } else if (components.minute > 0) {
        formatter.allowedUnits = NSCalendarUnitMinute;
    } else {
        formatter.allowedUnits = NSCalendarUnitSecond;
    }

    NSString *formatString = NSLocalizedString(@"%@ ago", @"Used to say how much time has passed. e.g. '2 hours ago'");

    return [NSString stringWithFormat:formatString, [formatter stringFromDateComponents:components]];
}