Android convert date and time to milliseconds

Question

I have one date and time format as below:

Tue Apr 23 16:08:28 GMT+05:30 2013

I want to convert into milliseconds, but I actually dont know

Answer 1

Android 26 and higher

Conversation from epoch to UTC date time and Device date time

public class TimeConversionUtil {

public static long getCurrentEpochUTC() {
    return Instant.now(Clock.systemUTC()).toEpochMilli();
}

public static String deviceDateTimeString(long epochMilliUtc) {
    Instant instant = Instant.ofEpochMilli(epochMilliUtc);
    DateTimeFormatter formatter = DateTimeFormatter.ofPattern("MMM dd, yyyy, hh:mm:ss a", Locale.US).withZone(ZoneId.systemDefault());
    return formatter.format(instant);
}

public static String uTCDateTimeString(long epochMilliUtc) {
    Instant instant = Instant.ofEpochMilli(epochMilliUtc);
    DateTimeFormatter formatter = DateTimeFormatter.ofPattern("MMM dd, yyyy, hh:mm:ss a", Locale.US).withZone(ZoneId.of("UTC"));
    return formatter.format(instant);

}

public static long convertDateStringToLongUTC(String stringUTCDate) {
    DateTimeFormatter formatter = DateTimeFormatter.ofPattern("MMM dd, yyyy, hh:mm:ss a", Locale.ENGLISH);
    LocalDateTime localDate = LocalDateTime.parse(stringUTCDate, formatter);
    long timeInMilliseconds = localDate.atOffset(ZoneOffset.UTC).toInstant().toEpochMilli();
    return timeInMilliseconds;
}

}

@Test
public void timeConversionTest() {
    long currentTimeUtc = Instant.now(Clock.systemUTC()).toEpochMilli();
    String utc = TimeConversionUtil.uTCDateTimeString(currentTimeUtc);
    Long utcLongTime = TimeConversionUtil.convertDateStringToLongUTC(utc);
    String utc1 = TimeConversionUtil.uTCDateTimeString(utcLongTime);
    assertTrue(utc.equalsIgnoreCase(utc1));
}