Wrong data return from calender

Wrong data return from calender - android

I am trying to retrieve the number of week in a month.. actually today is the second week in november but I am getting it as 3
The code I am using is
Log.e("dfhkdjfk", Calendar.getInstance().get(Calendar.WEEK_OF_MONTH)+"");
please help me to figure it out.
Reference Time:
3:45 AM
Monday, November 9, 2015
Coordinated Universal Time (UTC)

Wrong.
For some country like France where Monday is the first day of the week, today is really the first day of the third week of November, as the first of november was a Sunday ( so the first week of november had one day... ).
You might use DAY_OF_WEEK_IN_MONTH which give you the number of time a day already happened starting from the beginning of the current month.
Otherwise check which day is considered as the first of the week and implement some logic to adapt it to your need.

You need to try below code with TimeZone which give correct Calendar.WEEK_OF_MONTH
Calendar calUs = Calendar.getInstance(TimeZone.getTimeZone("US/Eastern"), Locale.US);
int weekOfMonthUs = calUs.get(Calendar.WEEK_OF_MONTH);
System.out.println("Week of month is " + weekOfMonthUs);
O/P

Week of month is the week within the current month starting from Sunday to how many weeks have there been.
WEEK_OF_MONTH depends on the first day of the week. Not all calendars have Sunday has beginning of the week. For ex: France has Monday as first day of the week. So Before getting into this check the locale of the phone.

Related

android calendar change with device language

I'm stuck with one interesting problem.
I have a Calendar object with European style(? don't know how to call it right) i.e. week starts on Monday and ends on Sunday.
My issue appears when I change device language to English(U.S.). Calendar object changes its style to American i.e. week starts on Sunday and ends on Saturday.
Unfortunately I need week to start on Monday and end on Sunday but I can't understand how to do that.
I tried
calendar.setFirstDayOfWeek(Calendar.MONDAY);
calendar = Calendar.getInstance(Locale.FRANCE);
but it doesn't work.
Thanks in advance!

Days difference between local date objects

LocalDate today=LocalDate.now();
And the event date is:
eventDate=LocalDate.of(year, monthOfYear,dayOfMonth); (from the date picker dialog)
I'm trying to calculate the days difference between them... The shortest thing I have found is this:
int DaysDifference = Period.between(eventToDisplay.getEventDate(),today).getDays();
While the first object is "today", and the second one is "eventToDisplay.getEventDate()." It didn't work for me, it showed the wrong number of days.
I have also tried to do it like this:
eventToDisplay.getEventDate().compareTo(today)
Also didn't work...
I have also tried to do it without joda-time, because I had troubles with it, because of what I'm trying to do with date and time...
The other things I have found are long and complicated, and I thought maybe there is a better way, without the joda-time.
EDIT:
I have just tried this:
Calendar now = Calendar.getInstance();
Calendar chosenDate=Calendar.getInstance();
chosenDate.set(eventToDisplay.getEventDate().getYear(),eventToDisplay.getEventDate().getMonth().getValue(),eventToDisplay.getEventDate().getDayOfMonth());
long def= chosenDate.getTimeInMillis() - now.getTimeInMillis();
long DaysDifference =TimeUnit.MILLISECONDS.toDays(def);
Didn't work for me
EDIT:
This has worked for me:
LocalDate today=LocalDate.now();
Calendar now = Calendar.getInstance();
now.set(today.getYear(),today.getMonthValue(),today.getDayOfMonth());
Calendar chosenDate=Calendar.getInstance();
chosenDate.set(eventToDisplay.getEventDate().getYear(),eventToDisplay.getEventDate().getMonthValue(),eventToDisplay.getEventDate().getDayOfMonth());
long def= chosenDate.getTimeInMillis() - now.getTimeInMillis();
long daysDifference =TimeUnit.MILLISECONDS.toDays(def);

you can use something like this:
Calendar now = Calendar.getInstance();
Calendar end=Calendar.getInstance();
end.set(<year>, <month>, <day>);
long def= end.getTimeInMillis() - now.getTimeInMillis();
long days =TimeUnit.MILLISECONDS.toDays(def);

java.time
Since you can use LocalDate from java.time, the modern Java date and time API, I warmly recommend that you stick to java.time. Calculating the difference is simple and straightforward when you know how:
LocalDate today = LocalDate.now(ZoneId.systemDefault());
LocalDate eventDate = LocalDate.of(2021, 5, 5);
long differenceDays = ChronoUnit.DAYS.between(today, eventDate);
System.out.println("Difference is " + differenceDays + " days.");
Output when I ran today (APril 18 in my tme zone):
Difference is 17 days.
If your date picker uses 0-based months (some date pickers insanely use 0 for January through 11 for December), remember to add 1 to the month number before passing it to LocalDate.
What went wrong in all your attempts?
int DaysDifference = Period.between(eventToDisplay.getEventDate(),today).getDays();
The Period class represents a period of years, months and days. Since months have different lengths, a Period does not correspond to any exact number of days, so it’s not the right class to use here. You tried to use its getDays method, which gives you the days component of the period, not the months or the years. So if the two days are less than a month apart, you will get the correct result, otherwise not. If for example the two dates are 1 month 3 days apart, you will only get the 3 days.
The Calendar class used in more than one of your attempts is poorly designed and long outdated. Counting days correctly with it would be truly cumbersome, so no wonder that your attempts gave the wrong results.
Both of your attempts are wrong for at least two reasons:
A Calendar has a date and a time of day. So by finding the difference in milliseconds and dividing by the number of milliseconds that you think are in a day, you will get different results depending on the time of day that happens to be in each of your Calendar objects. Your code calls Calendar.getInstance() twice. In an extreme situation your code may run across midnight so the time in the first Calendar will be close to 23:59:59 and in the second close to 00:00, which will almost certainly give you an error of 1 day.
A day is not always 24 hours. Summer time (DST) is the most frequent but not the only reason why a date is sometimes 23 hours, 25 hours or some other length. If for example you try to count days across the spring forward where a day is only 23 hours or 23 hours 30 minutes, your code will count 1 day too few.
Furthermore this line from the snippet that you say that works is definitely wrong:
now.set(today.getYear(),today.getMonthValue(),today.getDayOfMonth());
You are using the 1-based month number from LocalDate, for example 4 for April, as a 0-based month number in Calendar, for example 4 would mean May. So your Calendar is off by 1 month. Since I haven’t got your complete code, is may in some cases balance out by another error that causes the other Calendar to be 1 month off too, I cannot know. Since months have different lengths, you will still get an error of up to 3 days sometimes.

Notification with every end of month

This is what i want add to my app. Notification with every end of month.
Example: Tomorrow is 1st day of next month. I want to show notification end day of month 28 or 29 for FEB, 30 or 31 for other months.
How can i do this?
help.
Thanks

You can do this using AlarmManager but problem with only February month.
you can use like this for setAlarm for every month unfortunately don't know how can handle for February. I think you can set Condition for February particularly .
alarmStartTime.add(Calendar.DAY_OF_MONTH, 30);

calendarview highlights wrong week

I have a CalendarView in my app, when the user selects a date by touching that date in the monthview, the correct date is selected (verified by adding debug statements in the code), but the week before is highlighted, so it looks as if the wrong date is selected.
I have found a work-around: if I set 'firstDayInWeek' to 1 the problem is solved, but by default the firstDayInweek is 2 (monday), and then this problem occurs.
Thank you very much!
Samsung S4 with API 21

I have had the same issue as you, using a Samsung S5 running API 21.
There are two workarounds that I have found, none of them is a good experience for our users :(
Force first day of the week to Sunday
calendarView.setFirstDayOfTheWeek(Calendar.SUNDAY);
Set a minimum and a maximum date for the calendar (be careful because not all of the dates work here). I was able to make it work properly setting a minimum date 2 months before the current date and maximum date 2 years after the current date. You can play with these values and find a good compromise between the limits and your user experience.
Calendar calendar = Calendar.getInstance();
calendar.set(Calendar.MONTH, calendar.get(Calendar.MONTH) - 2);
calendarView.setMinDate(calendar.getTimeInMillis());
calendar.set(Calendar.YEAR, calendar.get(Calendar.YEAR) + 2);
calendarView.setMaxDate(calendar.getTimeInMillis());
Unfortunately, this is the only way I could fix this issue, I hope it is useful for you.

Android how to map every next monday and thursday, 6 pm for the next four weeks to actual dates?

My app's user enters a few days from the week, and a few times a day when they need to get notified about something.
So in the SQLite DB I have the following information:
days of the week the alarm should go off
hours and minutes of the day the alarm should go off (might be a few times a day)
number of weeks
Now, how do I get this information and map it to a list of real dates, like June 2nd, 2014 15:30 for example?
Also, for the current week, all the reminders that are already passed, should be moved to the end of the queue.

Then you have to calculate date by yourself.
Assume 7 day a week.
For example : Tuesday in next 3 weeks
--> target day should be 7 x 2 + 2
Use Calendar object, they have method called add(field , value)
Prototype code for above sample:
Calendar c = Calendar.getInstance();
c.add(Calendar.DAY, 7x2 + 2);
Date date = c.getTime();
then your need object is date
Save this in miliseconds to db and use it later. Done :)

Develop Reference

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