如何将Kotlin日期的字符串或时间戳格式设置为我喜欢的格式？

Question

我从天气API获得两个版本的日期数据。第一个字符串是这样的：2019-08-07 :09:00，如下所示：1565209665。如何将其更改为一天或一天或一个月的名称？例如，星期一，八月。

我在几个配置中尝试过这样的方法，但它只在完整版本中工作。如果我猫什么东西，它就会抛出一个错误：

    var date = list.get(position).dt_txt
    val formatter = DateTimeFormatterBuilder()
        .appendPattern("yyyy-MM-dd HH:mm:ss").toFormatter()
    formatter.parse(date)

Answer 1

第一API格式：

val firstApiFormat = DateTimeFormatter.ofPattern("yyyy-MM-dd HH:mm:ss")
val date = LocalDate.parse("2019-08-07 09:00:00" , firstApiFormat)

Log.d("parseTesting", date.dayOfWeek.toString()) // prints Wednesday
Log.d("parseTesting", date.month.toString()) // prints August

第二个API格式：

val secondApiFormat = DateTimeFormatter.ofPattern("yyyy-MM-dd'T'HH:mm:ss'Z'")
val timestamp = 1565209665.toLong() // timestamp in Long


val timestampAsDateString = java.time.format.DateTimeFormatter.ISO_INSTANT
            .format(java.time.Instant.ofEpochSecond(timestamp))

Log.d("parseTesting", timestampAsDateString) // prints 2019-08-07T20:27:45Z


val date = LocalDate.parse(timestampAsDateString, secondApiFormat)

Log.d("parseTesting", date.dayOfWeek.toString()) // prints Wednesday
Log.d("parseTesting", date.month.toString()) // prints August

Answer 2

这真的很简单

val dateFormated = SimpleDateFormat("dd/MM/yyyy").format(trans.created_date.toDate())

我希望这对每个人都有用，多亏了https://www.datetimeformatter.com/how-to-format-date-time-in-kotlin/

Answer 3

尝试使用以下代码获取dayOfWeek和月份名称

码

到字符串日期

方法

fun getAbbreviatedFromDateTime(dateTime: String, dateFormat: String, field: String): String? {
    val input = SimpleDateFormat(dateFormat)
    val output = SimpleDateFormat(field)
    try {
        val getAbbreviate = input.parse(dateTime)    // parse input
        return output.format(getAbbreviate)    // format output
    } catch (e: ParseException) {
        e.printStackTrace()
    }

    return null
}

*如何使用

val monthName=getAbbreviatedFromDateTime("2019-08-07 09:00:00","yyyy-MM-dd HH:mm:ss","MMMM")
    println("monthName--"+monthName)

    val dayOfWeek=getAbbreviatedFromDateTime("2019-08-07 09:00:00","yyyy-MM-dd HH:mm:ss","EEEE")
    println("dayOfWeek--"+dayOfWeek)

To Timemillis

方法

 fun convertStringToCalendar( timeMillis: Long) {
    //get calendar instance
    val calendarDate = Calendar.getInstance()
    calendarDate.timeInMillis = timeMillis
    val month=getAbbreviatedFromDateTime(calendarDate,"MMMM");
    val day=getAbbreviatedFromDateTime(calendarDate,"EEEE");
    Log.d("parseTesting", month)// prints August
    Log.d("parseTesting",day)// prints Wednesday
}


fun getAbbreviatedFromDateTime(dateTime: Calendar, field: String): String? {
    val output = SimpleDateFormat(field)
    try {
        return output.format(dateTime.time)    // format output
    } catch (e: Exception) {
        e.printStackTrace()
    }

    return null
}

使用

 val timestamp = "1565209665".toLong()

    convertStringToCalendar(timestamp)