same day of last month ios

Question

Is there any way using NSCalender you can get same day of last month?

I am using a calender which shows user 1 month like the iPad calender when they click on the button I want to move to previous month but should select the same day as before.

I want to just do

[components setMonth:([components month] - 1)];

but this will create problems when I are moving from a month with 31 days to month with 30 days and selected day is 31st.

I was able to find examples for android but not iOS.

android example

Any help would be appreciated

This will occur with leap years also.... So what you want one day less or one day more? Facebook shows 28th as birthday for 29th Feb born on non-leap years!!! — Anoop Vaidya, Jan 25 '13 at 20:01
what is your requirement if its 31st December on subtracting 1 month what it should be? — Zaheer Ahmed, Jan 25 '13 at 20:38

score 3 · Accepted Answer · edited May 23 '17 at 12:18

3

Check out this link.

It's about adding one month, but you could probably do the same with subtracting.

Change

[dateComponents setMonth:1];

into

[dateComponents setMonth:-1];

edited May 23 '17 at 12:18

Community

1
1

answered Jan 25 '13 at 20:19

Chris Loonam

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This might lead to an invalid date. (Dec 31st -> Nov 31st) – Thorsten Jan 25 '13 at 20:57
This answer is correct (it won't result in Nov 31st). If you see an incorrect date when you log it, it's probably because `NSDate`'s `description` method formats it as GMT. Make sure that you show both dates with the same time zone. – omz Jan 25 '13 at 21:40

score 1 · Answer 2 · edited May 23 '17 at 10:30

Seems there is no obvious "right" answer and no "built-in" answer.

As Chris's "simple" idea may lead to invalid dates, you may have to handle the edge-cases.

Pseudocode to deal with day-month-year:

if month = December start with day-1-(year-1), else day-(month-1)-year [using dateComponents]
check if this a valid date (using NSDateFormatter like in this question
repeat subtracting one day until you reach a valid date

Another idea:

prevMonthDate = startDate;
Repeat
    prevMonthDate = prevMonthDate - 1 day
Until (Month(prevMonthDate) < Month(startDate) Or Year(prevMonthDate) < Year(startDate))
    And (Day(prevMonthDate) <= Day(startDate))

This requires working with NSDate and NSDateComponents, check out the Date and Time Programming Guide.

same day of last month ios

2 Answers2