How to Get the number of hours between two or more months?

Question

Am implementing a default range picker and I would like the user to specify the default duration range

So in my ranges I have

1 day = 24 hours
3 days = 24 * 3 hours
1 week = 24 * 7 hours
1 month

My logic is using the total hours in a day and multiply by total days

But now the problem comes in when the range becomes more than 2 months, since some months have 31 day, 28 days and even 30days

SO how do I go about determining example the last two months from now the number of hours, so that in my calendar I can simply

 Calendar cal = Calendar.getInstance();
 cal.add(Calendar.HOUR, cal.get(Calendar.HOUR) - hours) //stuck here

SO in simple terms example

today being april 2, how do I get the number of hours from january 2 to april 2.

SO in my own logic it for more than one month it should look like:

 Date today = Date.now();    
 LocalDate userday = LocalDate.of(less number of months); 
 Period diff = Period.between(userday, today);

in that case, how come `1 day = 24 hours` and `3 days = 36 hours`, I think it should be `3 days = 72 hours` — Lucifer, Apr 02 '18 at 08:31

Ashish Pardhiye · Answer 1 · 2018-04-02T10:41:05.800

2

Try this

Calendar calendar = Calendar.getInstance();
calendar.set(2018,Calendar.JANUARY, 2);
Long min = calendar.getTimeInMillis();
calendar.set(2018,Calendar.APRIL, 2);
Long max = calendar.getTimeInMillis();
Long range = (max - min) / (60*60*1000); //no_of_hours

Updated Answer:

Calendar calendar = Calendar.getInstance();
    Long max = calendar.getTimeInMillis();
    int currMonth = calendar.get(Calendar.MONTH);
    int currYear = calendar.get(Calendar.YEAR);
    int currDate = calendar.get(Calendar.DAY_OF_MONTH);
    int expMonth = currMonth + 3/*no_of_month*/;
    int expYear = currDate;
    int expDate = calendar.get(Calendar.DAY_OF_MONTH);
    while (expMonth > 11) {
        expMonth = expMonth - 12;
        expYear = expYear + 1; // will increment year as next month falls in next year 
    }
    calendar.set(expYear, expMonth, expDate);
    Long min = calendar.getTimeInMillis();
    Long range = (max - min) / (60 * 60 * 1000); //no_of_hours

edited Apr 02 '18 at 10:41

answered Apr 02 '18 at 08:33

Ashish Pardhiye

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January was just an example the range is dynamic that is , Jnuary, feb augusut ... etc not a must it be january – Geoff Apr 02 '18 at 08:38
You can set it as required or as selected by user – Ashish Pardhiye Apr 02 '18 at 08:39
the user is specifying a range eg 3 months so am trying to get from the code which are the three months from the current date, the user is not selecting the months – Geoff Apr 02 '18 at 08:45

Lucifer · Accepted Answer · 2018-04-02T08:56:16.153

2

You can substract month like below,

Date referenceDate = new Date();
Calendar c = Calendar.getInstance(); 
c.setTime(currentDate); 
c.add(Calendar.MONTH, -3);
return c.getTime();

Then get hours from following code.

long diff = currentDate.getTime() - previousDate.getTime();
long hours = minutes / (1000 * 60 * 60);

edited Apr 02 '18 at 08:56

answered Apr 02 '18 at 08:49

Lucifer

29,392
25
90
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now how do i get the previous date, Since as in the question the user is specifying the duration eg 3 months which mean its 3 months from today, so how will i get the previous date 3 months back from today. – Geoff Apr 02 '18 at 08:51
@GEOFFREYMWANGI, any progress ? – Lucifer Apr 02 '18 at 10:17

score 0 · Answer 3 · answered Apr 02 '18 at 08:31

You need the number of days within a month.

Its easy once you determine which month it is:

Take a look at this: Number of days in particular month of particular year?

Once you have the month just calculate number of hours for it and keep adding until you satisfy your range.

How to Get the number of hours between two or more months?

3 Answers3