CODEWITHSUNDEEP
javadatecalendar
Marc Rasmussen
Marc Rasmussen

Reputation: 20565

Working with Date and Calendar

I have a datepicker where the user selects a date and then a checkbox on what type of period he wants to get the date from. For example:

User selects the 1. of November and selects the checkbox "Month" in this case the end date will be increased by 1 and even if this sound simple enough its slowly starting to annoy me alot!

The problem is that Java doesnt have a great date object that works for this kind of thing so i thought that i would use Calendar but it isnt easy to increment a calendar date take for instance the following example:

endDate.set(startDate.YEAR, startDate.MONTH+1, startDate.DATE);

in theory this would increment the month by one being one larger than the start date. This works in about 90 % of the months EXECPT from December if you increase the month by 1 in December then the integer month return 13 same thing happens for startDate.DATE; and startDate.Year;

My question is isnt there an easier way to do this? i could make a ton of If sentences but i really think that it is kinda redundant.

Upvotes: 0

Views: 117

Answers (3)

Brian Agnew
Brian Agnew

Reputation: 272407

The standard recomendation here is to look at Joda-Time (see here for more info). It's a much more consistent/capable API with none of the threading issues that plague the standard Java date/formatting APIs and as such is widely used and accepted.

In terms of what you want above, I would suggest something like:

LocalDate d = ...
LocalDate nd = d.plusMonths(1);

The above will correctly handle month/year rollovers.

Upvotes: 1

Aleksandr M
Aleksandr M

Reputation: 24406

Use add method of java.util.Calendar.

endDate.set(startDate.YEAR, startDate.MONTH, startDate.DATE);
if(some_condition) {
   endDate.add(Calendar.MONTH, 1);
}

Upvotes: 2

Uwe Plonus
Uwe Plonus

Reputation: 9974

You can use Calendar.add() to add values to the calendar value, e.g. Calendar.add(Calendar.MONTH, 1) this adds one month and takes into account that January is after December.

Upvotes: 1

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