How to check if the date belongs to current week or not?

Question

I have the date and time stored in preferences as Long:

// put
SharedPreferences settings =
    PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
settings.edit().putLong("pref_datetime", System.currentTimeMillis()).commit();
// get
Date date2 = new Date(settings.getLong("pref_datetime", 0));

Once date is extracted, how could I check if it belongs to the current week (starting on Monday) or not?

Si Kelly · Accepted Answer · 2016-01-15T21:04:19.130

5

You can use a Calendar instance to create this Monday and next Monday Date instances based on the current date then check that your date lies between them.

Calendar c = Calendar.getInstance();
c.setFirstDayOfWeek(Calendar.MONDAY);

c.set(Calendar.DAY_OF_WEEK, Calendar.MONDAY);
c.set(Calendar.HOUR_OF_DAY, 0);
c.set(Calendar.MINUTE, 0);
c.set(Calendar.SECOND, 0);
c.set(Calendar.MILLISECOND, 0);

Date monday = c.getTime();

Date nextMonday= new Date(monday.getTime()+7*24*60*60*1000);

boolean isThisWeek = date2.after(monday) && date2.before(nextMonday);

edited Jan 15 '16 at 21:04

answered May 29 '14 at 09:55

Si Kelly

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3
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shouldn't it be `c.set(Calendar.HOUR_OF_DAY, 0);` instead of `c.set(Calendar.HOUR, 0);`? – Rupesh Jan 15 '16 at 11:40
Thanks Rupesh, yes HOUR_OF_DAY is preferable – Si Kelly Jan 15 '16 at 21:11
Thanks!!! This worked for me :) – josher932 Apr 08 '16 at 22:25

Thilo · Answer 2 · 2014-05-29T10:08:40.043

2

~~You can construct a Calendar, and use getField(int) to get both the Calendar.YEAR and the Calendar.WEEK_OF_YEAR. When those are the same, the two Dates are from the same week.~~

When constructing the Calendar, also call setFirstDayOfWeek(Calendar.MONDAY) to make sure the weeks start on Monday (if you don't, it depends on the current locale).

After @SiKelly's objection that this won't work reliably in the end of December, beginning of January:

Compare WEEK_OF_YEAR.
If not equal, it is a different week.
If equal, it could be the wrong year, but that is hard to check. So just also check that the difference in getTime() is less than 8 * 24 * 60 * 60 * 1000 (eight days to be on the safe side).

(you could do step 3 first. then you avoid having to construct the calendar at all in many cases).

edited May 29 '14 at 10:08

answered May 29 '14 at 09:42

Thilo

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Thanks for pointing at `Calendar.YEAR` as well – Mehul Joisar May 29 '14 at 09:52
1

I have had trouble relying on week of year before as it is a somewhat slippery concept. The weeks at the beginning and end of the year straddle 2 years, and therefore you may get 52 or 1 depending on the implementation. – Si Kelly May 29 '14 at 09:59
@SiKelly: Good catch. That would be a problem. – Thilo May 29 '14 at 10:02
@SiKelly: just for gaining knowledge, I would like to know that, will my approach work in all situations? – Mehul Joisar May 29 '14 at 13:14
@MehulJoisar: I think not. You can have Dec 30th and Jan 1st in the same week (will be 52 or 1), but in different years. So checking for same year won't work. – Thilo May 29 '14 at 13:18
@Thilo: but I have added condition for checking year as well weeknumber both.won't it work fine in such situation? – Mehul Joisar May 29 '14 at 13:24
`if(current_year==year )` that will be false for Dec 30th and Jan 1st. – Thilo May 29 '14 at 13:25
@Thilo: I got your point. you're right.it won't work. – Mehul Joisar May 29 '14 at 13:26

score 1 · Answer 3 · answered May 29 '14 at 09:49

You can use Calendar to calculate week number for today and your date also,then simpy try to match it,

// put
SharedPreferences settings =
    PreferenceManager.getDefaultSharedPreferences(getApplicationContext());
settings.edit().putLong("pref_datetime", System.currentTimeMillis()).commit();
// get
Date date2 = new Date(settings.getLong("pref_datetime", 0));              

          Calendar calendar = Calendar.getInstance();
          calendar.setFirstDayOfWeek(Calendar.MONDAY);
          int current_year = calendar.get(Calendar.YEAR);
          int current_week_number = calendar.get(Calendar.WEEK_OF_YEAR);
          calendar.setTime(date2);
          int year = calendar.get(Calendar.YEAR);
          int week_number= calendar.get(Calendar.WEEK_OF_YEAR);
          if(current_year==year && current_week_number==week_number)
          {
              //same
          }
          else
          {
              //different
          }

score 0 · Answer 4 · answered May 29 '14 at 10:24

try this

private boolean  is_ThisWeek(Date date2){

        Date now =new Date(System.currentTimeMillis());
        int diffInDays = (int)( (now.getTime() - date2.getTime()) 
                 / (1000 * 60 * 60 * 24) );

        Calendar calendar = Calendar.getInstance();
        calendar.setTime(now);
        int reslut = calendar.get(Calendar.DAY_OF_WEEK);
        int days_before = get_days_before(reslut);

        if (diffInDays<days_before) {
            Toast.makeText(this, "this week", Toast.LENGTH_SHORT).show();
            return true;
        }else {
            Toast.makeText(this,"not this week", Toast.LENGTH_SHORT).show();
            return false;
        }
     }
    int get_days_before(int reslut){
        int days_before = 0;
        switch (reslut) {
        case Calendar.MONDAY:
            days_before=1;
            break;
        case Calendar.TUESDAY:
            days_before=2;
            break;
        case Calendar.WEDNESDAY:
            days_before=3;
            break;
        case Calendar.THURSDAY:
            days_before=4;
            break;
        case Calendar.FRIDAY:
            days_before=5;
            break;
        case Calendar.SATURDAY:
            days_before=6;
            break;
        case Calendar.SUNDAY:
            days_before=7;
            break;
        }
        return days_before;
    }

How to check if the date belongs to current week or not?

4 Answers4