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I have 4 calendars, startCal, endCal, reminderCal and today. today simply gets a Calendar.getInstance() for the current date/time, whereas the 3 others go through the same method for selecting date&time using Androids date/time pickers.
startCal and endCal are working just fine
if(startCal.after(endCal)){ // handle error }
however, reminderCal.before(today) doesn't return true, even when I purposely set the reminderCal before the current date.
Also, when printing all the times, the reminderCal doesn't have any time (Time=?) and areFieldsSet=false, but if I submit a second time the time gets updated, although the before() method still doesn't work!
Everything seems to work except for the the else if (reminderCal.before(today))
public boolean validInput(){
if(startCal.after(endCal)){
//THIS WORKS
timeError.setText(getString(R.string.error_event_end_early));
isOk = false;
Log.e(TAG, "validInput: Event ends before it starts");
}
if(hasReminder.isChecked()){
if(reminderDate.getText().toString().matches("")) {
// THIS WORKS
reminderError.setText(R.string.error_no_reminder);
isOk = false;
Log.e(TAG, "validInput: No reminder set");
} else if (reminderCal.before(today)){
// THIS DOESN'T WORK. Why?
reminderError.setText(R.string.error_reminder_early);
isOk = false;
Log.e(TAG, "validInput: Reminder too early " + reminderCal.toString());
} else if(reminderCal.after(startCal)){
//THIS WORKS
reminderError.setText(R.string.error_reminder_late);
isOk = false;
Log.e(TAG, "validInput: Reminder too late");
}
return isOk;
}
Log.e(TAG, "Debugging: \n" +
"strCalandar: " + startCal.toString() + "\n" +
"endCalandar: " + endCal.toString() + "\n" +
"remCalandar: " + reminderCal.toString() + "\n" +
"todCalandar: " + today.toString() + "\n");
}
today = Calander.getInstance(); with no further adjustments. The other calendars get the date/time from these methods.
public void showDatePickerDialog(final EditText text, final Calendar cal){
Log.d(TAG, "showDatePickerDialog: Open");
DialogFragment datePicker = new DatePickerFragment();
((DatePickerFragment) datePicker).setOnDateChosenListener(new DatePickerFragment.OnDateChosenListener() {
#Override
public void onDateChosen(int year, int month, int day) {
text.setText(String.format("%02d/%02d/%04d", day, month, year));
cal.set(year, month, day);
}
});
datePicker.show(getSupportFragmentManager(), "DatePicker");
}
public void showTimePickerDialog(final EditText text, final Calendar cal){
Log.d(TAG, "showTimePickerDialog: Open");
DialogFragment timePicker = new TimePickerFragment();
((TimePickerFragment) timePicker).setOnTimeChosenListener(new TimePickerFragment.OnTimeChosenListener() {
#Override
public void onTimeChosen(int hour, int min) {
text.setText(String.format("%02d:%02d", hour, min));
cal.set(Calendar.HOUR_OF_DAY, hour);
cal.set(Calendar.MINUTE, min);
}
});
timePicker.show(getSupportFragmentManager(), "TimePicker");
}
Output in Logcat:
strCalandar: java.util.GregorianCalendar[time=1566152201478,areFieldsSet=true,areAllFieldsSet=true,lenient=true,zone=libcore.util.ZoneInfo[id="Europe/London",mRawOffset=0,mEarliestRawOffset=0,mUseDst=true,mDstSavings=3600000,transitions=242],firstDayOfWeek=2,minimalDaysInFirstWeek=4,ERA=1,YEAR=2019,MONTH=7,WEEK_OF_YEAR=33,WEEK_OF_MONTH=3,DAY_OF_MONTH=18,DAY_OF_YEAR=230,DAY_OF_WEEK=1,DAY_OF_WEEK_IN_MONTH=3,AM_PM=1,HOUR=7,HOUR_OF_DAY=19,MINUTE=16,SECOND=41,MILLISECOND=478,ZONE_OFFSET=0,DST_OFFSET=3600000]
endCalandar: java.util.GregorianCalendar[time=1566152201478,areFieldsSet=true,areAllFieldsSet=true,lenient=true,zone=libcore.util.ZoneInfo[id="Europe/London",mRawOffset=0,mEarliestRawOffset=0,mUseDst=true,mDstSavings=3600000,transitions=242],firstDayOfWeek=2,minimalDaysInFirstWeek=4,ERA=1,YEAR=2019,MONTH=7,WEEK_OF_YEAR=33,WEEK_OF_MONTH=3,DAY_OF_MONTH=18,DAY_OF_YEAR=230,DAY_OF_WEEK=1,DAY_OF_WEEK_IN_MONTH=3,AM_PM=1,HOUR=7,HOUR_OF_DAY=19,MINUTE=16,SECOND=41,MILLISECOND=478,ZONE_OFFSET=0,DST_OFFSET=3600000]
remCalandar: java.util.GregorianCalendar[time=?,areFieldsSet=false,areAllFieldsSet=false,lenient=true,zone=libcore.util.ZoneInfo[id="Europe/London",mRawOffset=0,mEarliestRawOffset=0,mUseDst=true,mDstSavings=3600000,transitions=242],firstDayOfWeek=2,minimalDaysInFirstWeek=4,ERA=1,YEAR=2019,MONTH=7,WEEK_OF_YEAR=31,WEEK_OF_MONTH=1,DAY_OF_MONTH=2,DAY_OF_YEAR=214,DAY_OF_WEEK=6,DAY_OF_WEEK_IN_MONTH=1,AM_PM=1,HOUR=5,HOUR_OF_DAY=17,MINUTE=18,SECOND=41,MILLISECOND=478,ZONE_OFFSET=0,DST_OFFSET=3600000]
todCalandar: java.util.GregorianCalendar[time=1562775401478,areFieldsSet=true,areAllFieldsSet=true,lenient=true,zone=libcore.util.ZoneInfo[id="Europe/London",mRawOffset=0,mEarliestRawOffset=0,mUseDst=true,mDstSavings=3600000,transitions=242],firstDayOfWeek=2,minimalDaysInFirstWeek=4,ERA=1,YEAR=2019,MONTH=6,WEEK_OF_YEAR=28,WEEK_OF_MONTH=2,DAY_OF_MONTH=10,DAY_OF_YEAR=191,DAY_OF_WEEK=4,DAY_OF_WEEK_IN_MONTH=2,AM_PM=1,HOUR=5,HOUR_OF_DAY=17,MINUTE=16,SECOND=41,MILLISECOND=478,ZONE_OFFSET=0,DST_OFFSET=3600000]
reminderCal.before(today) should return true if reminder date is set before current date
They have tried to explain it in this part of the docs:
set(f, value) changes calendar field f to value. In addition, it sets an internal member variable to indicate that
calendar field f has been changed. Although calendar field f is
changed immediately, the calendar's time value in milliseconds is not
recomputed until the next call to get(), getTime(),
getTimeInMillis(), add(), or roll() is made. Thus, multiple
calls to set() do not trigger multiple, unnecessary computations. As
a result of changing a calendar field using set(), other calendar
fields may also change, depending on the calendar field, the calendar
field value, and the calendar system. In addition, get(f) will not
necessarily return value set by the call to the set method after the
calendar fields have been recomputed. The specifics are determined by
the concrete calendar class.
Example: Consider a GregorianCalendar originally set to August 31, 1999. Calling set(Calendar.MONTH, Calendar.SEPTEMBER) sets the date to September 31, 1999. This is a temporary internal representation that
resolves to October 1, 1999 if getTime()is then called. However, a
call to set(Calendar.DAY_OF_MONTH, 30) before the call to getTime()
sets the date to September 30, 1999, since no recomputation occurs
after set() itself.
So since you call cal.set(Calendar.HOUR_OF_DAY, hour); and cal.set(Calendar.MINUTE, min);, the time gets temporarily undefined, which is why the question mark is printed from toString.
I have not been able to reproduce the reported behaviour of before and after, but it seems reasonable to assume that they also don’t work correctly until get or one of the mentioned getXxx methods is called.
This is only one of the very confusing aspects of the design of the Calendar class. The good solution is to switch to using java.time, the modern Java date and time API.
This question already has answers here:
Java - Check if array contains 3 consecutive dates
(4 answers)
Closed 5 years ago.
I have an array of unique dates from each time the user completes a task. I want to check if the dates within the array are consecutive from and including todays date.
If the array contains dates: "2017/6/2, 2017/6/3, 2017/6/4, 2017/6/5" then based on today's date being 2017/6/5 the function would return 4 as there are 4 consecutive dates from and including today.
If the array contains dates "2017/6/2, 2017/6/3, 2017/6/4" then it would return 0 as the array does not include today's date. Otherwise the count would be broken upon a non consecutive date.
List<Date> dateList = new ArrayList<Date>();
int count = 0;
Date todayDate = new Date();
for (int i=0; i<dateList.size(); i++){
// Check if dates within the array are consecutive from todayDate, if so then increment count by 1.
}
If you're using Java 8, consider using the new java.time API. It's easier, less bugged and less error-prone than the old APIs.
If you're using Java <= 7, you can use the ThreeTen Backport, a great backport for Java 8's new date/time classes. And for Android, there's the ThreeTenABP (more on how to use it here).
Although you can also use JodaTime, it's being discontinued and replaced by the new APIs, do I don't recommend start a new project with joda. Even in joda's website it says: "Note that Joda-Time is considered to be a largely “finished” project. No major enhancements are planned. If using Java SE 8, please migrate to java.time (JSR-310).".
As you want to compare just the date (day/month/year), and not the time (hour/minute/second), the best choice is to use the LocalDate class. For java 8, this class is in java.time package, and in ThreeTen Backport, the package is org.threeten.bp. But the classes and methods names are the same.
The code would be like this:
public int count(List<LocalDate> dateList, LocalDate today) {
if (!dateList.contains(today)) { // today is not in the list, return 0
return 0;
}
int count = 0;
LocalDate prev = dateList.get(0); // get first date from list
for (int i = 1; i < dateList.size(); i++) {
LocalDate next = dateList.get(i);
if (prev.plusDays(1).equals(next)) {
// difference between dates is one day
count++;
} else {
// difference between dates is not 1
// Do what? return 0? throw exception?
}
prev = next;
}
return count + 1; // didn't count the first element, adding 1
}
Testing this method:
List<LocalDate> dateList = new ArrayList<>();
dateList.add(LocalDate.of(2017, 6, 2));
dateList.add(LocalDate.of(2017, 6, 3));
dateList.add(LocalDate.of(2017, 6, 4));
dateList.add(LocalDate.of(2017, 6, 5));
LocalDate today = LocalDate.now();
System.out.println(count(dateList, today)); // 4
Another test (when today is not in the list)
List<LocalDate> dateList = new ArrayList<>();
dateList.add(LocalDate.of(2017, 6, 2));
dateList.add(LocalDate.of(2017, 6, 3));
dateList.add(LocalDate.of(2017, 6, 4));
LocalDate today = LocalDate.now();
System.out.println(count(dateList, today)); // 0
Notes:
As it wasn't specified what to do when the days are not consecutive (return 0 or throw exception), I left this part commented. But it should be straightforward to add this to the code
If you want to convert java.util.Date to LocalDate, you can do as follows (using the code of this answer, full explanation is in this link in case you have any questions):
public LocalDate convert(Date date) {
return date.toInstant().atZone(ZoneId.systemDefault()).toLocalDate();
}
// if your Date has no toInstant method, try this:
public LocalDate convert(Date date) {
return Instant.ofEpochMilli(date.getTime()).atZone(ZoneId.systemDefault()).toLocalDate();
}
I understood that you want to check for consecutive days (so, a 1-day difference between the dates). But if you want to check if the previous date is before the next (no matter how many days), you can change the if (prev.plusDays(1).equals(next)) to if (prev.isBefore(next))
I'm not sure if that's the case, but if you want, you can also parse a String directly to a LocalDate (so you don't need to create lots of Date objects), using a DateTimeFormatter:
DateTimeFormatter formatter = DateTimeFormatter.ofPattern("yyyy/M/d");
LocalDate d = LocalDate.parse("2017/6/2", formatter); // 2017-06-02
There are a lot of ways to write it more clear:
Use new Date API;
Use libraries;
But, in such case, with usage of old Date classes, I would do that in such a way:
public static void main(String[] args) {
long millisInDay = TimeUnit.DAYS.toMillis(1);
List<Date> dates = Arrays.asList(new Date("2017/6/2"), new Date("2017/6/3"), new Date("2017/6/4"), new Date("2017/6/5"));
System.out.println(getSequentialNumber(millisInDay, dates));
}
private static int getSequentialNumber(long millisInDay, List<Date> dates) {
int count = 0;
Date now = setMidnight(Calendar.getInstance().getTime());
for (int i = dates.size() - 1; i >= 0; i--) {
Date date = setMidnight(dates.get(i));
if (date.getTime() == now.getTime()) {
count++;
}
now.setTime(now.getTime() - millisInDay);
}
return count;
}
private static Date setMidnight(Date date) {
Calendar calendar = Calendar.getInstance();
calendar.setTime(date);
calendar.set(Calendar.MINUTE, 0);
calendar.set(Calendar.MILLISECOND, 0);
calendar.set(Calendar.HOUR, 0);
calendar.set(Calendar.SECOND, 0);
calendar.set(Calendar.HOUR_OF_DAY, 0);
return calendar.getTime();
}
If I understand the requirement correctly, you have an array of Date objects, ordered by date, and guaranteed not to have two Date objects for the same day, but possibly with gaps between the days. Your goal is to return the length of the maximum sub-array that contains only consecutive days and also includes the current day, or to return 0 if there is no such sub-array. The current day may fall anywhere inside that sub-array, not necessarily at the beginning or end.
It's not clear if you need to support crossing year boundaries, but I'll assume so. I also assume that all the Date objects in the list are for the same time zone which is also the time zone for the device on which you are running. If that's not the case, you should refer to this answer for more information on testing whether two Date objects refer to the same day.
It's fairly simple to do this if you work with Calendar objects instead of Date objects. You don't need any third-party libraries, as both Date and Calendar are parts of the standard Android API. I suggest doing this in two phases: first search for the current date in the array and then scan in both directions for either a gap in the dates or an array boundary. Then just count how far you could go in each direction.
public int getDateSpanCount(List<Date> dateList) {
final int n = dateList.size();
final Calendar today = Calendar.getInstance();
final Calendar other = Calendar.getInstance();
int count = 0;
// First search for today in the date array
int posToday = -1;
for (int i=0; i<n; i++) {
other.setTime(dateList.get(i));
if (areSameDay(today, other)) {
posToday = i;
break;
}
}
// If today is in the list, count the size of the sub-array containing today
if (posToday >= 0) {
count++; // count today, at least
final Calendar probe = Calendar.getInstance();
// scan backwards from position of today's date
for (int prevPos = posToday - 1; prevPos >= 0; prevPos--) {
final Date prev = dateList.get(prevPos);
probe.setTime(prev);
other.add(Calendar.DAY_OF_YEAR, -1);
if (areSameDay(probe, other)) {
count++;
other.setTime(prev);
} else {
break;
}
}
// reset the other time
other.setTime(today.getTime());
// scan forward from position of today's date
for (int nextPos = posToday + 1; nextPos < n; nextPos++) {
final Date next = dateList.get(nextPos);
probe.setTime(next);
other.add(Calendar.DAY_OF_YEAR, 1);
if (areSameDay(probe, other)) {
count++;
other.setTime(next);
} else {
break;
}
}
}
return count;
}
/** Test whether two Calendar objects are set to the same day */
private static boolean areSameDay(Calendar c1, Calendar c2) {
// see discussion above if dates may not all be for the local time zone
return c1.get(Calendar.YEAR) == c2.get(Calendar.YEAR) &&
c1.get(Calendar.DAY_OF_YEAR) == c2.get(Calendar.DAY_OF_YEAR);
}
I'm create a java webapp and I have to create a consecutive number that should starts every month. The idea is to have something like this:
01-0414 / 02-0414 /03-0414 / 04-0414
where the first two digits should be the consecutive number, and the last four digits are the month and year.
I'm using spring 3.2.2 and hibernate 4.2.6. I really appreciate any help about this.
thanks
Well, your question is not clear. But as far as I understand you need help to get the date. You can use Calendar() or Date(), use something like this Calendar.get(Calendar.MONTH)to get the month and year (or simply parse to string and substring where you want).
Regarding the number at the beginning, I will assume (again, since you are not clear) that it is passed as an input. So basically you concatenate that with the "-" and the output of the previous step; the date thingy.
I hope I helped!
If you want to encode your web app string using a sequence number that gets reset to 1 at the beginning of each month, you could use a singleton class instance to hold the month and sequence number state. The code string generator method checks whether the month has changed, and if so, it resets the internal current month to the new month, and resets the effective internal sequence number to 1.
Here is the generator class (see below for an example of how to use it):
public class MySequenceCodeStringGenerator {
private static final int generatorMonth;
private static final int generatorSequenceNumber;
// Create a singleton instance to hold month and sequence number state.
private static final MySequenceCodeStringGenerator INSTANCE = new MySequenceCodeStringGenerator();
private MySequenceCodeStringGenerator() {
generatorMonth = getCurrentMonth();
generatorSequenceNumber = 0;
}
/////////////////////////
// PUBLIC functions:
/////////////////////////
// Get the singleton instance:
public static MySequenceCodeStringGenerator getInstance() {
return INSTANCE;
}
// Get the formatted sequence code string:
public static int getSequenceCodeString {
int sequenceNumber = getSequenceNumber();
Calendar now = Calendar.getInstance();
int year = now.get(Calendar.YEAR);
int month = now.get(Calendar.MONTH);
String yearString = String.valueOf(year);
return String.format( "%02d-%02d%s", sequenceNumber, month+1, yearString.substring(2) );
}
// Get the current month:
private int getCurrentMonth() {
Calendar now = Calendar.getInstance();
return now.get(Calendar.MONTH);
}
// Get the singleton sequence number. Update if this is a new month.
private int getSequenceNumber() {
currentMonth = getCurrentMonth();
if ( currentMonth != generatorMonth ) {
generatorMonth = currentMonth;
generatorSequenceNumber = 0;
}
return ++generatorSequenceNumber;
}
}
Here's an example of how you use the generator class:
String myWebAppString = MySequenceCodeStringGenerator.getInstance().getSequenceCodeString();
Problem: I have a list containg hours, for example:
08:15:00
08:45:00
09:00:00
12:00:00
...
application is allowing user to make an appointment for a specific hour let'say: 8:15:00, each meeting takes half an hour.
Question: How to determine if there is a slot needed for appointment like this? I know that Calendar class have methods before() nad after(), but it doesn'solve my problem. I mean if there is appointment at 12:00 and another one at 12:00, how to prevent before making another one at 12:15?
edit:
I've tried using methods I mentioned before, like:
Calendar cal1 = Calendar.getInstance(); // for example 12:00:00
Calendar cal2 = Calendar.getInstance(); // for exmaple 12:30:00
Calendar userTime = Calendar.getInstance(); // time to test: 12:15:00
if(user.after(cal1)&& user.before(cal2)){
... // do sth
}
Check if the date to check is between the two provided:
SimpleDateFormat sdf = new SimpleDateFormat("dd/MM/yyyy hh:mm");
Date before = sdf.parse("07/05/2012 08:00");
Date after = sdf.parse("07/05/2012 08:30");
Date toCheck = sdf.parse("07/05/2012 08:15");
//is toCheck between the two?
boolean isAvailable = (before.getTime() < toCheck.getTime()) && after.getTime() > toCheck.getTime();
To book for a determinate hour, I would do a class with two dates and a method to check this:
public class Appointment{
private Date start;
private Date end;
public boolean isBetween(Date toCheck){....}
}
Then you can simply do an Schedule class extending ArrayList, adding a method isDateAvailable(Date toCheck), iterating the list of Appointments and checking that there is no one conflicting.
I'd have some kind of appointment class with either a start timestamp and a duration or a start time and an end time. Then when adding new appointments to the schedule, check that the appointment with the start time before the new appointment doesn't run over the start time of the proposed new appointment.
Well how you would do it specifically depends on how you are storing your data, format, etc., but generally what you would do is simply check if there is an appointment for any time between the requested time to the requested time + requested length.
// Example (using int time(1 = 1 minute), assuming that appointments can only be at 15min intervals)
boolean isHalfHourTimeSlotAvaliable(int time) {
for (int i = 0; i < appointments.size(); i++) {
if (appointments.get(i).time == time || appointments.get(i).time == time + 15) {
return false;
}
}
return true;
}
I've a code to get year, month and day for one of my application.
package com.cera.hyperionUtils;
import java.util.*;
public class HypDate {
public static int curdate(int field)
{
//1. Specify integer 1 for YEAR, 2 for MONTH, 5 DAY_OF_MONTH
Calendar c = new GregorianCalendar();
c.setLenient(true); //Allow overflow
//2. Extract and Return result
if (field == 2) {
field = c.get(Calendar.MONTH) + 1;
}
return c.get(field);
}
public static void main(String[] args)
{
System.out.println(HypDate.curdate(2));
}
}
But when i pass 2 it is giving 0 year and day prints correctly.....Also i was trying to make month as double digit. (like 01 for 1)
Can someone please help me....? (I''m very new to java coding)
Rather than returning these one by one, you may just want to use a SimpleDateFormat to format it.
Say I want a date as year-month-day:
// Necessary imports
import java.text.DateFormat;
import java.text.SimpleDateFormat;
// Declare class and stuff before this
public static String getFormattedDate() {
DateFormat df = new SimpleDateFormat("yyyy-MM-dd");
return df.format(new Date());
}
public static void main(String[] args) {
System.out.println(getFormattedDate());
}
Outputs 2010-10-29
Edit:
Since you just want the month, you can do this:
public static String getFormattedMonth() {
DateFormat df = new SimpleDateFormat("MM");
return df.format(new Date());
}
if (field == 2) {
field = c.get(Calendar.MONTH) + 1;
}
return c.get(field);
You retrieve the correct month as an index and then use that index to retrieve another field that will be unknown and related in how the constants are saved. Just return the value before, without using a second get.
Maybe you meant
if (field == 2) {
field = Calendar.MONTH;
}
return c.get(field) + 1;
but I don't get why you are redefining that constants instead that use the one already provided..
The problem comes from the fact that when you are getting the month information, you call c.get() twice, which you don't want to do. Instead, you should directly return after you get the first value
//1. Specify integer 1 for YEAR, 2 for MONTH, 5 DAY_OF_MONTH
Calendar c = new GregorianCalendar();
c.setLenient(true); //Allow overflow
//2. Extract and Return result
if (field == Calendar.MONTH) {
return c.get(field) + 1; //because Java months are 0-based
} else {
return c.get(field);
}