NSDate 完整风格但没有年份

Question

我正在使用适用于 iPhone 的 Objective C 并且有一个我想以完整样式显示但没有年份的 NSDate。现在我正在使用下面的代码，但它也显示年份，我不希望这样。由于我想以正确的区域格式显示日期，因此我不能只删除最后的年份，因为在某些国家/地区，年份不会在最后，而是在中间或开始。

NSDate *testdate = [NSDate date];
NSDateFormatter *dateFormattertest = [[NSDateFormatter alloc] init];
[dateFormattertest setDateStyle:NSDateFormatterFullStyle];
[dateFormattertest setTimeStyle:NSDateFormatterNoStyle];
NSString *formattedDateString = [dateFormattertest stringFromDate:testdate];
NSLog(formattedDateString);

In US this give me:
Thursday, January 14, 2010

In Sweden this give me:
torsdag, 2010 januari 14

解决办法是什么？还有一个问题，我在哪里可以找到有关如何使用 NSDateFormatter 的 setDateFormat 的信息？我找不到有关 API 中不同字母代表什么的信息。

Answer 1

斯威夫特 5

来自@Joss 的回复：

extension Date {
    
    func output(_ components: String = "EEEEMMMMd") -> String{
        
        let currentLocale: Locale = Locale.current

        // Set the date components you want
        let dateComponents: String = components

        // The components will be reordered according to the locale
        let dateFormat = DateFormatter.dateFormat(fromTemplate: dateComponents, options: 0, locale: currentLocale)

        let formatter =  DateFormatter()
        
        formatter.dateFormat = dateFormat

        return formatter.string(from: self)
    }
}

Answer 2

斯威夫特 4

extension Date {
    public func formattedFromComponents(styleAttitude: DateFormatter.Style, year: Bool = false, month: Bool = false, day: Bool = false, hour: Bool = false, minute: Bool = false, second: Bool = false, locale: Locale = Locale.current) -> String {
        let long = styleAttitude == .long || styleAttitude == .full
        let short = styleAttitude == .short
        var comps = ""

        if year { comps += long ? "yyyy" : "yy" }
        if month { comps += long ? "MMMM" : (short ? "MM" : "MMM") }
        if day { comps += long ? "dd" : "d" }

        if hour { comps += long ? "HH" : "H" }
        if minute { comps += long ? "mm" : "m" }
        if second { comps += long ? "ss" : "s" }
        let format = DateFormatter.dateFormat(fromTemplate: comps, options: 0, locale: locale)
        let formatter = DateFormatter()
        formatter.dateFormat = format
        return formatter.string(from: self)
    }
}

Answer 3

@Joss 对 Swift 扩展做出了很好的回答：

extension NSDate {
    func formattedFromCompenents(styleAttitude: NSDateFormatterStyle, year: Bool = true, month: Bool = true, day: Bool = true, hour: Bool = true, minute: Bool = true, second: Bool = true) -> String {
        let long = styleAttitude == .LongStyle || styleAttitude == .FullStyle
        var comps = ""

        if year { comps += long ? "yyyy" : "yy" }
        if month { comps += long ? "MMMM" : "MMM" }
        if day { comps += long ? "dd" : "d" }

        if hour { comps += long ? "HH" : "H" }
        if minute { comps += long ? "mm" : "m" }
        if second { comps += long ? "ss" : "s" }

        let format = NSDateFormatter.dateFormatFromTemplate(comps, options: 0, locale: NSLocale.currentLocale())
        let formatter = NSDateFormatter()
        formatter.dateFormat = format
        return formatter.string(from: self)
    }
}

Answer 4

斯威夫特 3

    let template = "EEEEdMMM"

    let format = DateFormatter.dateFormat(fromTemplate: template, options: 0, locale: NSLocale.current)
    let formatter = DateFormatter()
    formatter.dateFormat = format

    let now = Date()
    let whatYouWant = formatter.string(from: now) // ex: Sunday, Mar 5

使用template 来满足您的需求。

文档和示例here 可帮助您确定所需的模式。

Answer 5

这是一个在标签上仅显示月份日期的快捷选项：

let todaysDate: NSDate = NSDate()
let formatter = NSDateFormatter()
formatter.dateFormat = "MMMM dd"
self.todayLabel.text = formatter.stringFromDate(todaysDate)

Answer 6

我知道这是一个相当老的问题，但这是我在 SO 上找到的唯一一个与我遇到的相同问题的问题。

这里使用的关键方法是：dateFormatFromTemplate

您想设置格式，而不是设置样式：

NSDate *testdate = [NSDate date];

NSLocale *currentLocale = [NSLocale currentLocale];

// Set the date components you want
NSString *dateComponents = @"EEEEMMMMd";

// The components will be reordered according to the locale
NSString *dateFormat = [NSDateFormatter dateFormatFromTemplate:dateComponents options:0 locale:currentLocale];
NSLog(@"Date format for %@: %@", [currentLocale displayNameForKey:NSLocaleIdentifier value:[currentLocale localeIdentifier]], dateFormat);

NSDateFormatter *dateFormatter =[[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:dateFormat];

NSString *formattedDateString = [dateFormatter stringFromDate:testdate];
NSLog(formattedDateString);

特别感谢：http://oleb.net/blog/2011/11/working-with-date-and-time-in-cocoa-part-2/