How to format in Kotlin date in string or timestamp to my preferred format?

Question

I'm getting date data from weather API in two versions. The first one is just string like this: 2019-08-07 09:00:00 and like this: 1565209665 . How do I change it to just the name of the day or day and month? For example Monday, August.

I tried something like this in few configurations but it works only in full version. If I cat something then it throws an error:

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

Answer 1

First API format:

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

Second API format:

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

Try this code to get dayOfWeek and month name

Code

To String Date

Method

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
}

*How to use

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

Methods

 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
}

Use

 val timestamp = "1565209665".toLong()

    convertStringToCalendar(timestamp)

Answer 3

Try this

val stringDate="2019-08-07 09:00:00"

val dateFormat_yyyyMMddHHmmss = SimpleDateFormat(
    "yyyy-MM-dd HH:mm:ss", Locale.ENGLISH
)
val date = dateFormat_yyyyMMddHHmmss.parse(stringDate)
val calendar = Calendar.getInstance()
calendar.setTime(date)

val dayOfWeekString = calendar.getDisplayName(Calendar.DAY_OF_WEEK, Calendar.LONG, Locale.ENGLISH)

Output:

dayOfWeekString : wednesday

val timeInMillis = 1565242471228
val calendar = Calendar.getInstance()
calendar.setTimeInMillis(timeInMillis)

val dayOfWeekString = calendar.getDisplayName(Calendar.DAY_OF_WEEK, Calendar.LONG, Locale.ENGLISH)

Answer 4

val parsedDate: String? = if(monthOfYear < 10 && dayOfMonth > 10){
                            "${dayOfMonth}/0${monthOfYear + 1}/${year}"

                        } else if(dayOfMonth < 10 && monthOfYear > 10) {
                            "0${dayOfMonth}/${monthOfYear + 1}/${year}"

                        } else if(dayOfMonth < 10 && monthOfYear < 10){
                            "0${dayOfMonth}/0${monthOfYear + 1}/${year}"
                        }else{
                            "0${dayOfMonth}/${monthOfYear + 1}/${year}"

                        }

                        date?.text = parsedDate

I tried different things but in Date picker this works for me in kotlin

Answer 5

This is really simple

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

I hope this works for everybody, thanks to https://www.datetimeformatter.com/how-to-format-date-time-in-kotlin/