how to get the time from current time to x time later in miliseconds in java - android?

Question

I'm trying to get the time between current time to the target time (later) in milliseconds format.

For example I want to get the time between today that is 29/01/2022 to 10/02/2022 in milliseconds format.

How to do this in Java?

In fact I'm trying to do something after x time and this code I'm using :

SimpleDateFormat hour = new SimpleDateFormat("HH");
SimpleDateFormat minute = new SimpleDateFormat("mm");

Date date = new Date();

Calendar calnow = Calendar.getInstance();

calnow.set(Calendar.HOUR_OF_DAY, Integer.parseInt(hour.format(date)));

calnow.set(Calendar.MINUTE,Integer.parseInt(minute.format(date)));

alarmManager.set(AlarmManager.RTC_WAKEUP,   calnow.getTimeInMillis() + 10000, this.pendingIntent);

Answer 1

I finally found an easy to use solution, I will share it maybe someone need that

This is the full class :

And I accept any other suggestions, or edit.

import android.content.Intent;
import android.widget.Toast;

import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.Locale;
import java.util.concurrent.TimeUnit;

public class Time {



    public static int getMilisecondsBetween(String date1, String date2){
      //long daysNumber = 0;
       long diffInMillies = 0;
       try {
           SimpleDateFormat sdf = new SimpleDateFormat("dd/MM/yyyy", Locale.ENGLISH);
           Date firstDate = sdf.parse(date1);
           Date secondDate = sdf.parse(date2);
           diffInMillies = Math.abs(secondDate.getTime() - firstDate.getTime());
          // daysNumber = TimeUnit.DAYS.convert(diffInMillies, TimeUnit.MILLISECONDS);
       } catch (Exception e){
           System.out.println(e);
       }
       return (int) diffInMillies;
    }

    public static int getDaysNumberBetween(String date1, String date2){
        long daysNumber = 0;
        long diffInMillies = 0;
        try {
            SimpleDateFormat sdf = new SimpleDateFormat("dd/MM/yyyy", Locale.ENGLISH);
            Date firstDate = sdf.parse(date1);
            Date secondDate = sdf.parse(date2);
            diffInMillies = Math.abs(secondDate.getTime() - firstDate.getTime());
           daysNumber = TimeUnit.DAYS.convert(diffInMillies, TimeUnit.MILLISECONDS);
        } catch (Exception e){
            System.out.println(e);
        }
        return (int) daysNumber;
    }

    public static int daysFromNowTo(String date){
        long daysNumber = 0;
        long diffInMillies = 0;
        try {
            SimpleDateFormat sdf = new SimpleDateFormat("dd/MM/yyyy", Locale.getDefault());

            Date c = Calendar.getInstance().getTime();
            String currentDate = sdf.format(c);

            Date firstDate = sdf.parse(currentDate);
            Date secondDate = sdf.parse(date);
            diffInMillies = Math.abs(secondDate.getTime() - firstDate.getTime());
            daysNumber = TimeUnit.DAYS.convert(diffInMillies, TimeUnit.MILLISECONDS);
        } catch (Exception e){
            System.out.println(e);
        }
        return (int) daysNumber;
    }

    public static int milisFromNowTo(String date){
        long diffInMillies = 0;
        try {
            SimpleDateFormat sdf = new SimpleDateFormat("dd/MM/yyyy", Locale.getDefault());

            Date currentDate = Calendar.getInstance().getTime();
            Date secondDate = sdf.parse(date);
            diffInMillies = Math.abs(secondDate.getTime() - currentDate.getTime());
        } catch (Exception e){
            System.out.println(e);
        }
        return (int) diffInMillies;
    }

    public static int convertToMilis(int time, String cmd){
        long milis = 0;
        try {
            switch (cmd){

                case "w" :
                    milis = time * 604800000;
                    break;
                case "d" :
                    milis = time * 86400000;
                    break;
                case "h" :
                    milis = time * 3600000;
                    break;
                case "m" :
                    milis = time * 60000;
                    break;
                case "s" :
                    milis = time * 1000;
                    break;
            }

        } catch (Exception e){
            System.out.println(e);
        }
        return (int) milis;
    }
}

to use it is very easy, example :

to get all milliseconds between two specific dates :

int milis = Time.getMilisecondsBetween("04/02/2022", "10/02/2022");

to get days number between two specific dates :

int daysNumber = Time.getDaysNumberBetween("04/02/2022", "10/02/2022");

to get days number from current date to specific date :

int daysFromToday = Time.daysFromNowTo("10/02/2022");

to get milliseconds count from today to specific date :

int millis =  Time.milisFromNowTo("10/02/2022");

convert any time, periode, ...ect to milliseconds :

. w = weeks

. d = days

. h = hours

. m = minutes

. s = seconds

// here 3 days to milliseconds as example

int millis = Time.convertToMilis(3, "d");

Answer 2

tl;dr

Duration
.between( 
    LocalDate
    .of( 2022 , Month.JANUARY , 29 )
    .atStartOfDay( 
        ZoneId.of( "Asia/Tokyo" ) 
    ) 
    , 
    LocalDate
    .of( 2022 , 2 , 10 )
    .atStartOfDay( 
        ZoneId.of( "Asia/Tokyo" ) 
    )  
)
.toMillis()

See this code run live at IdeOne.com.

1036800000

Details

Avoid legacy date-time classes

Never use the terrible legacy date-time classes such as Date and Calendar. Use only java.time classes.

Android 26+ includes an implementation of java.time. For earlier Android, the latest tooling makes most of the functionality available via “API desugaring”.

java.time

Define your start and end dates.

LocalDate startDate = LocalDate.of( 2022 , Month.JANUARY , 29 ) ;
LocalDate endDate = LocalDate.of( 2022 , 2 , 10 ) ;

Determine the first moment of the day for each date. This requires a time zone. The day starts at an earlier moment in the east than in the west.

ZoneId z = ZoneId.of( "America/Edmonton" ) ;
ZonedDateTime start = startDate.atStartOfDay( z ) ;
ZonedDateTime end = endDate.atStartOfDay( z ) ;

Calculate elapsed time. Use Duration class.

Duration d = Duration.between( start , end ) ;

Extract a count of milliseconds. Beware of potential data loss, as Duration may contain microseconds and nanoseconds.

long millis = d.toMillis() ;

All of this has been covered many times on Stack Overflow. So search to learn more.