I'm trying to set up constraints for a Material Date Range Picker Dialog. The idea is to limit the range of the selectable dates from the current day to the same day one month later.
I have a method to build the constraints:
public CalendarConstraints.Builder setCalendarConstraints() {
CalendarConstraints.Builder constraints = new CalendarConstraints.Builder();
long min = setMinDate();
long max = setMaxDate();
constraints.setStart(min);
constraints.setEnd(max);
return constraints;
}
And the two following methods are used to get the minimum and maximum dates:
// Maximum date for the date picker is the current date + 1 month
public long setMaxDate() {
LocalDate now = LocalDate.now();
LocalDate max;
if (now.getMonthValue() == 12) {
max = LocalDate.of(now.getYear(), 1, now.getDayOfMonth());
max.plusYears(1);
} else {
max = LocalDate.of(now.getYear(), now.getMonth().plus(1), now.getDayOfMonth());
}
return max.atStartOfDay(ZoneOffset.UTC).toInstant().toEpochMilli();
}
Everything was working when I was testing my app two weeks ago, so I think the problem comes from that we are now in December. I tried to add a year to the current year when we are in December, when it looks like it doesn't work as I have the following error:
java.lang.IllegalArgumentException: current Month cannot be after end Month
The java.time classes use immutable objects.
The method LocalDate::plusYears() doesn't work on the LocalDate itself. As the Javadoc says, it returns a new object, a copy of the original LocalDate Object but with with one year added.
So you'll need to write:
max = max.plusYears(1);
By the way, you don't need to check for December.
LocalDate max = LocalDate.now().plusMonths(1)
does the trick whether you're in December or not.
try
LocalDate.now().plusMonths( 1 );
for max
Related
I would like to reach date that is -1month +1day, which should be 0month difference from start date.
Using joda-time 2.10:
int day = 29;
LocalDate date1 = new LocalDate(new GregorianCalendar(2019, Calendar.JUNE, day).getTime());
LocalDate date2 = date1.plusMonths(-1).plusDays(1);
Months.monthsBetween(date1,date2).getMonths(); // returns 0 <- it's OK
but the same code with input int day = 30; returns -1 which is bad.
That looks like an inconsequence in Joda library.
That's a case: shift by -1month change date by shift month number and keep day number no greater than in input, but month-difference between dates are depend on day of month.
Do you know any alternative and working solution?
I have found JSR-310 with ChronoUnit - that solves the problem, BUT it needs Java8. I would like to stay on Java7.
The signature of ChronoUnit.DAYS.between method is:
public long between(Temporal temporal1Inclusive,
Temporal temporal2Exclusive)
So the last date is not included as it relates the example:
LocalDate from = LocalDate.now();
LocalDate to = from.plusDays(1);
ChronoUnit.DAYS.between(from, to); // Result is 1
Is there another function to get 2 days in that expression?
Otherwise I only see that I could do that as the following:
LocalDate from = LocalDate.now();
LocalDate to = from.plusDays(1);
ChronoUnit.DAYS.between(from, to.plusDays(1)); // Result is 2
Actually NO, but you can use the following code:
ChronoUnit.DAYS.between(from, to) + 1;
+1 adds 1 day to the difference between those two local dates so we can say that the last date is included.
I have a date and a number and want to check if this date and this number occurs in a list of other dates within:
+-20 date intervall with the same number
so for example 1, 1.1.2013 and 1,3.1.2013 should reuturn false.
I tried to implement the method something like that:
private List<EventDate> dayIntervall(List<EventDate> eventList) throws Exception {
List<EventDate> resultList = new ArrayList<EventDate>();
for (int i = 0; i < eventList.size(); i++) {
String string = eventList.get(i).getDate();
Date equalDate = new SimpleDateFormat("dd.MM.yyyy", Locale.GERMAN).parse(string);
for (int j = 0; j < eventList.size(); j++) {
String string1 = eventList.get(i).getDate();
Date otherDate = new SimpleDateFormat("dd.MM.yyyy", Locale.GERMAN).parse(string1);
if (check number of i with number of j && check Date) {
//do magic
}
}
}
return resultList;
}
The construction of the iteration method is not that hard. What is hard for me is the date intervall checking part. I tried it like that:
boolean isWithinRange(Date testDate, Date days) {
return !(testDate.before(days) || testDate.after(days));
}
However that does not work because days are not takes as days. Any suggestions on how to fix that?
I really appreciate your answer!
You question is difficult to follow. But given its title, perhaps this will help…
Span Of Time In Joda-Time
The Joda-Time library provides a trio of classes to represent a span of time: Interval, Period, and Duration.
Interval
An Interval object has specific endpoints that lie on the timeline of the Universe. A handy contains method tells if a DateTime object occurs within those endpoints. The beginning endpoint in inclusive while the last endpoint is exclusive.
Time Zones
Note that time zones are important, for handling Daylight Saving Time and other anomalies, and for handling start-of-day. Keep in mind that while a java.util.Date seems like it has a time zone but does not, a DateTime truly does know its own time zone.
Sample Code
Some code off the top of my head (untested)…
DateTimeZone timeZone = DateTimeZone.forID( "Europe/Berlin" );
DateTime dateTime = new DateTime( yourDateGoesHere, timeZone );
Interval interval = new Interval( dateTime.minusDays( 20 ), dateTime.plusDays( 20 ) );
boolean didEventOccurDuringInterval = interval.contains( someOtherDateTime );
Whole Days
If you want whole days, call the withTimeAtStartOfDay method to get first moment of the day. In this case, you probably need to add 21 rather than 20 days for the ending point. As I said above, the end point is exclusive. So if you want whole days, you need the first moment after the time period you care about. You need the moment after the stroke of midnight. If this does not make sense, see my answers to other questions here and here.
Note that Joda-Time includes some "midnight"-related methods and classes. Those are no longer recommended by the Joda team. The "withTimeAtStartOfDay" method takes their place.
DateTime start = dateTime.minusDays( 20 ).withTimeAtStartOfDay();
DateTime stop = dateTime.plusDays( 21 ).withTimeAtStartOfDay(); // 21, not 20, for whole days.
Interval interval = new Interval( start, stop );
You should avoid java.util.Date if at all possible. Using the backport of ThreeTen (the long awaited replacement date/time API coming in JDK8), you can get the number of days between two dates like so:
int daysBetween(LocalDate start, LocalDate end) {
return Math.abs(start.periodUntil(end).getDays());
}
Does that help?
You can get the number of dates in between the 2 dates and compare with your days parameter. Using Joda-Time API it is relatively an easy task: How do I calculate the difference between two dates?.
Code:
SimpleDateFormat format = new SimpleDateFormat("dd.MM.yyyy", Locale.GERMAN);
Date startDate = format.parse("1.1.2013");
Date endDate = format.parse("3.1.2013");
Days d = Days.daysBetween(new DateTime(startDate), new DateTime(endDate));
System.out.println(d.getDays());
Gives,
2
This is possible using Calendar class as well:
Calendar cal = Calendar.getInstance();
cal.setTime(startDate);
System.out.println(cal.fieldDifference(endDate, Calendar.DAY_OF_YEAR));
Gives,
2
This 2 can now be compared to your actual value (20).
Is it possible to add weekdays to joda time?
For instance, if current date is Friday 01/03, date + 1 should return Monday 04/03, rather than 02/03.
As far as I know there is no built-in method to automatically do this for you in Joda Time. However, you could write your own method, that increments the date in a loop until you get to a weekday.
Note that, depending on what you need it for exactly, this could be (much) more complicated than you think. For example, should it skip holidays too? Which days are holidays depends on which country you're in. Also, in some countries (for example, Arabic countries) the weekend is on Thursday and Friday, not Saturday and Sunday.
LocalDate newDate = new LocalDate();
int i=0;
while(i<days)//days == as many days as u want too
{
newDate = newDate.plusDays(1);//here even sat and sun are added
//but at the end it goes to the correct week day.
//because i is only increased if it is week day
if(newDate.getDayOfWeek()<=5)
{
i++;
}
}
System.out.println("new date"+newDate);
Be aware that iterating through adding N days one at a time can be relatively expensive. For small values of N and/or non performance sensitive code, this is probably not an issue. Where it is, I'd recommend minimizing the add operations by working out how many weeks and days you need to adjust by:
/**
* Returns the date that is {#code n} weekdays after the specified date.
* <p>
* Weekdays are Monday through Friday.
* <p>
* If {#code date} is a weekend, 1 weekday after is Monday.
*/
public static LocalDate weekdaysAfter(int n, LocalDate date) {
if (n == 0)
return date;
if (n < 0)
return weekdaysBefore(-n, date);
LocalDate newDate = date;
int dow = date.getDayOfWeek();
if (dow >= DateTimeConstants.SATURDAY) {
newDate = date.plusDays(8 - dow);
n--;
}
int nWeeks = n / 5;
int nDays = n % 5;
newDate = newDate.plusWeeks(nWeeks);
return ( (newDate.getDayOfWeek() + nDays) > DateTimeConstants.FRIDAY)
? newDate.plusDays(nDays + 2)
: newDate.plusDays(nDays);
public LocalDate getBusinessDaysAddedDate(LocalDate localDate, int businessDays){
LocalDate result;
if(localDate.getDayOfWeek().getValue() + businessDays > 5) {
result = localDate.plusDays(2);
}
result = localDate.plusDays(businessDays);
return result;
}
In order to work with Date instead of LocalDate, refer https://stackoverflow.com/a/47719540/12794444 for the conversions.
Class YearMonthDay is deprecated and you shouldn't use it. If you change to simple DateTime you can obtain the week day by calling:
dateTime.getDayOfWeek();
For Friday it will be 5.
One of the approaches can be making a custom addDays method which should look something like that:
addDays(DateTime dateTime, int days) {
for(int i=0;i<days;i++){
dateTime.plusDays(1);
if(dateTime.getDayOfWeek()==6) dateTime.plusDays(2); // if Saturday add 2 more days }
}
In my app I´m saving when I last updated some data from my server.
Therefore I used:
long time = Calendar.getInstance().getTimeInMillis();
Now I want that the data is updated twice a year at 03.03 and 08.08.
How can I check wheater one of these two date boarders were crossed since last update?
Change them to time in mseconds and compare:
Calendar c = Calendar.getInstance();
c.set(Calendar.MONTH, Calendar.MARCH);
c.set(Calendar.DAY_OF_MONTH, 3);
long time2= c.getTimeInMillis();
c.set(Calendar.MONTH, Calendar.AUGUST);
c.set(Calendar.DAY_OF_MONTH, 8);
long time3= c.getTimeInMillis();
if(time>time2){
//Logic
if(time>time3){
//Logic
}
}
There is something very important which took me a while to figure it out and can be very helpful to people out there, if you are looking for an answer to any of the following questions this is for you:
Why is my date not showing correctly?
Why even when I set the time manually it is not showing right?
Why is the month and the year showing one day less than the one that I set?
For some reason Java sorts the months values like an array, what I mean is that for Java January is 0 and DECEMBER is 11. Same happens for the year, if you set December as month 12 and year as 2012, and then try to do a "system.out.println" of the month and the year, it will show my month as January and the year as 2013!!
so what should you do?
Calendar cal = new GregorianCalendar();
cal.set(2012, 11, 26); // the date I want to input is 26/12/2012 (for Java, 11 is December!)
NOW WHAT IS THE CORRECT WAY TO GET THAT DATE TO SEE IT ON THE SCREEN?
if you try to "system.out.println of yourCalendar.DATE, yourCalendar.MONTH and yourCalendar.YEAR," THAT WILL NOT SHOW YOU THE RIGHT DATE!!!!
If you want to display the dates you need to do the following:
System.out.println (calact.get (calact.DATE));
// displays day
System.out.println (calact.get (calact.MONTH)+1);
//add 1 remember it saves values from 0-11
System.out.println (calact.get (calact.YEAR));
// displays year
NOW IF YOU ARE HANDLING STRINGS THAT REPRESENT DATES, OR....
IF YOU NEED TO COMPARE DATES BETWEEN RANGES , LET'S SAY YOU NEED TO KNOW IF DATE "A" WILL TAKE PLACE WITHIN THE NEXT 10 DAYS....THIS....IS.....FOR....YOU!!
In my case I was working with a string that had format "15/07/2012", I needed to know if that date would take place within the next 10 days, therefore I had to do the following:
1 get that string date and transform it into a calendar ( StringTokenizer was used here )
this is very simple
StringTokenizer tokens=new StringTokenizer(myDateAsString, "/");
do nextToken and before returning the day, parse it as integer and return it.
Remember for month before returning substract 1.
I will post the code for the first you create the other two:
public int getMeD(String fecha){
int miDia = 0;
String tmd = "0";
StringTokenizer tokens=new StringTokenizer(fecha, "/");
tmd = tokens.nextToken();
miDia = Integer.parseInt(tmd);
return miDia;
}
2 THEN YOU CREATE THE CALENDAR
Calendar cal = new GregorianCalendar(); // calendar
String myDateAsString= "15/07/2012"; // my Date As String
int MYcald = getMeD(myDateAsString); // returns integer
int MYcalm = getMeM(myDateAsString); // returns integer
int MYcaly = getMeY(myDateAsString); // returns integer
cal.set(MYcaly, MYcalm, MYcald);
3 get my current date (TODAY)
Calendar curr = new GregorianCalendar(); // current cal
calact.setTimeInMillis(System.currentTimeMillis());
4 create temporal calendar to go into the future 10 days
Calendar caltemp = new GregorianCalendar(); // temp cal
caltemp.setTimeInMillis(System.currentTimeMillis());
caltemp.add(calact.DAY_OF_MONTH, 10); // we move into the future
5 compare among all 3 calendars
here basically you ask if the date that I was given is for sure taking place in the future AND (&&) IF the given date is also less than the future date which had 10 days more, then please show me "EVENT WILL TAKE PLACE FOR SURE WITHIN THE NEXT 10 DAYS!!" OTHERWISE SHOW ME:
"EVENT WILL NOT TAKE PLACE WITHIN THE NEXT 10 DAYS".
if((cal.getTimeInMillis() > curr.getTimeInMillis()) && (cal.getTimeInMillis()< curr.getTimeInMillis()))
{ System.out.println ("EVENT WILL TAKE PLACE FOR SURE WITHIN THE NEXT 10 DAYS!!");}
else
{ System.out.println ("EVENT WILL *NOT* TAKE PLACE WITHIN THE NEXT 10 DAYS");}
ALRIGHT GUYS AND GIRLS I HOPE THAT HELPS. A BIG HUG FOR YOU ALL AND GOOD LUCK WITH YOUR PROJECTS!
PEACE.
YOAV.
If the comparison should involve only the year, month and day then you can use this method for check if c1 is before c2. Ugly, but works.
public static boolean before(Calendar c1, Calendar c2){
int c1Year = c1.get(Calendar.YEAR);
int c1Month = c1.get(Calendar.MONTH);
int c1Day = c1.get(Calendar.DAY_OF_MONTH);
int c2Year = c2.get(Calendar.YEAR);
int c2Month = c2.get(Calendar.MONTH);
int c2Day = c2.get(Calendar.DAY_OF_MONTH);
if(c1Year<c2Year){
return true;
}else if (c1Year>c2Year){
return false;
}else{
if(c1Month>c2Month){
return false;
}else if(c1Month<c2Month){
return true;
}else{
return c1Day<c2Day;
}
}
}
used compareTo method ..and this returns integer value .if returns -ve the days before in current date else return +ve the days after come current date