Android计算两个日期之间的天数

I have written the following code to find days between two dates

我写了以下代码来查找两个日期之间的天数

    startDateValue = new Date(startDate);
    endDateValue = new Date(endDate);
    long diff = endDateValue.getTime() - startDateValue.getTime();
    long seconds = diff / 1000;
    long minutes = seconds / 60;
    long hours = minutes / 60;
    long days = (hours / 24) + 1;
    Log.d("days", "" + days);

When start and end date are 2/3/2017 and 3/3/2017 respectively the number of days showing is 29.Though when they are of the same day it is showing 1.(The number of days one takes a leave.So if one takes a single day leave,he has to select same start and end date.So in this case he has taken two days leave).

当开始和结束日期分别是2017年2月3日和2017年3月3日时，显示的天数是29.虽然它们在同一天显示为1.（一天休假的天数。所以如果一个人休一天假，他必须选择相同的开始和结束日期。所以在这种情况下，他已经休了两天假。）

What am I doing wrong? Thank you for your time.

我究竟做错了什么？感谢您的时间。

7 个解决方案

#1

Your code for generating date object:

您生成日期对象的代码：

Date date = new Date("2/3/2017"); //deprecated

You are getting 28 days as answer because according to Date(String) constructor it is thinking day = 3,month = 2 and year = 2017

你得到28天作为答案，因为根据Date（String）构造函数，它认为day = 3，month = 2和year = 2017

You can convert String to Date as follows:

您可以将String转换为Date，如下所示：

String dateStr = "2/3/2017";
SimpleDateFormat sdf = new SimpleDateFormat("dd/MM/yyyy");
Date date = sdf.parse(dateStr);

Use above template to make your Date object. Then use below code for calculating days in between two dates. Hope this clear the thing.

使用上面的模板来制作Date对象。然后使用下面的代码计算两个日期之间的天数。希望这清楚这件事。

It can de done as follows:

它可以如下完成：

long diff = endDateValue.getTime() - startDateValue.getTime();
System.out.println ("Days: " + TimeUnit.DAYS.convert(diff, TimeUnit.MILLISECONDS));

Please check link

请检查链接

If you use Joda Time it is much more simple:

如果你使用Joda Time，它会更加简单：

int days = Days.daysBetween(date1, date2).getDays();

Please check JodaTime

请检查JodaTime

How to use JodaTime in Java Project

如何在Java Project中使用JodaTime

#2

What date format do you use? Is it d/M/yyyy or M/d/yyyy?

你使用什么日期格式？是d / M / yyyy还是M / d / yyyy？

d = day, M = month, yyyy = year

d =天，M =月，yyyy =年

(see: https://developer.android.com/reference/java/text/SimpleDateFormat.html)

（参见：https：//developer.android.com/reference/java/text/SimpleDateFormat.html）

Then the codes:

那么代码：

public static final String DATE_FORMAT = "d/M/yyyy";  //or use "M/d/yyyy"   

public static long getDaysBetweenDates(String start, String end) {
    SimpleDateFormat dateFormat = new SimpleDateFormat(DATE_FORMAT, Locale.ENGLISH);
    Date startDate, endDate;
    long numberOfDays = 0;
    try {
        startDate = dateFormat.parse(start);
        endDate = dateFormat.parse(end);
        numberOfDays = getUnitBetweenDates(startDate, endDate, TimeUnit.DAYS);
    } catch (ParseException e) {
        e.printStackTrace();
    }
    return numberOfDays;
}

And for getUnitBetweenDates method:

对于getUnitBetweenDates方法：

private static long getUnitBetweenDates(Date startDate, Date endDate, TimeUnit unit) {
    long timeDiff = endDate.getTime() - startDate.getTime();
    return unit.convert(timeDiff, TimeUnit.MILLISECONDS);
}

#3

public static int getDaysDifference(Date fromDate,Date toDate)
{
if(fromDate==null||toDate==null)
return 0;

return (int)( (toDate.getTime() - fromDate.getTime()) / (1000 * 60 * 60 * 24));
}

#4

Have look at this code , this is helpful for me ,hope it will help you.

看看这段代码，这对我有帮助，希望对你有帮助。

public String get_count_of_days(String Created_date_String, String Expire_date_String) {
SimpleDateFormat dateFormat = new SimpleDateFormat("dd/MM/yyyy", Locale.getDefault());

Date Created_convertedDate = null, Expire_CovertedDate = null, todayWithZeroTime = null;
try {
    Created_convertedDate = dateFormat.parse(Created_date_String);
    Expire_CovertedDate = dateFormat.parse(Expire_date_String);

    Date today = new Date();

    todayWithZeroTime = dateFormat.parse(dateFormat.format(today));
} catch (ParseException e) {
    e.printStackTrace();
}

int c_year = 0, c_month = 0, c_day = 0;

if (Created_convertedDate.after(todayWithZeroTime)) {
    Calendar c_cal = Calendar.getInstance();
    c_cal.setTime(Created_convertedDate);
    c_year = c_cal.get(Calendar.YEAR);
    c_month = c_cal.get(Calendar.MONTH);
    c_day = c_cal.get(Calendar.DAY_OF_MONTH);

} else {
    Calendar c_cal = Calendar.getInstance();
    c_cal.setTime(todayWithZeroTime);
    c_year = c_cal.get(Calendar.YEAR);
    c_month = c_cal.get(Calendar.MONTH);
    c_day = c_cal.get(Calendar.DAY_OF_MONTH);
}


/*Calendar today_cal = Calendar.getInstance();
int today_year = today_cal.get(Calendar.YEAR);
int today = today_cal.get(Calendar.MONTH);
int today_day = today_cal.get(Calendar.DAY_OF_MONTH);
*/

Calendar e_cal = Calendar.getInstance();
e_cal.setTime(Expire_CovertedDate);

int e_year = e_cal.get(Calendar.YEAR);
int e_month = e_cal.get(Calendar.MONTH);
int e_day = e_cal.get(Calendar.DAY_OF_MONTH);

Calendar date1 = Calendar.getInstance();
Calendar date2 = Calendar.getInstance();

date1.clear();
date1.set(c_year, c_month, c_day);
date2.clear();
date2.set(e_year, e_month, e_day);

long diff = date2.getTimeInMillis() - date1.getTimeInMillis();

float dayCount = (float) diff / (24 * 60 * 60 * 1000);

return ("" + (int) dayCount + " Days");

}

}

#5

Does Android fully support java-8? If yes you can simple use ChronoUnit class

Android完全支持java-8吗？如果是，您可以简单地使用ChronoUnit类

LocalDate start = LocalDate.of(2017,2,3);
LocalDate end = LocalDate.of(2017,3,3);

System.out.println(ChronoUnit.DAYS.between(start, end)); // 28

or same thing using formatter

或者使用格式化程序

DateTimeFormatter formatter = DateTimeFormatter.ofPattern("M/d/yyyy");
LocalDate start = LocalDate.parse("2/3/2017",formatter);
LocalDate end = LocalDate.parse("3/3/2017",formatter);

System.out.println(ChronoUnit.DAYS.between(start, end)); // 28

#6

Very simple, just use Calendar, create two instances for the two dates, convert to milliseconds, subtract and convert to days (rounded up)... like this, basically:

很简单，只需使用Calendar，为两个日期创建两个实例，转换为毫秒，减去并转换为天数（向上舍入）......像这样，基本上：

Calendar startDate = Calendar.getInstance();
startDate.set(mStartYear, mStartMonth, mStartDay);
long startDateMillis = startDate.getTimeInMillis();

Calendar endDate = Calendar.getInstance();
endDate.set(mEndYear, mEndMonth, mEndDay);
long endDateMillis = endDate.getTimeInMillis();

long differenceMillis = endDateMillis - startDateMillis;
int daysDifference = (int) (differenceMillis / (1000 * 60 * 60 * 24));

#7

Be carefur if you'd like to use received integer e.g. to indicate specific day in custom calendar implementation. For example, I tried to go in m app from monthly calendar view to daily view and show daily content, by calculating dates from 1970-01-01 to selected one, and each 25-31th day of month shows me as one day earlier, because datesDifferenceInMillis / (24 * 60 * 60 * 1000); may return something like 17645,95833333333, and casting this to int you'll get value lower by 1. In this case correctly number of days you'll get by rounding received float by using NumberFormat class. Here's my code:

如果你想使用收到的整数，请小心指示自定义日历实现中的特定日期。例如，我尝试通过计算从1970-01-01到所选日期的日期，从每月日历视图到日常视图并显示每日内容，并且每月25-31天显示我为一天前，因为datesDifferenceInMillis /（24 * 60 * 60 * 1000）;可能返回类似于17645,95833333333的内容，并将其转换为int，您将得到的值降低1.在这种情况下，您可以通过使用NumberFormat类舍入收到的浮点数来获得正确的天数。这是我的代码：

NumberFormat numberFormat = NumberFormat.getInstance(Locale.getDefault());
numberFormat.setRoundingMode(RoundingMode.HALF_UP);
numberFormat.setMaximumFractionDigits(0);
numberFormat.setMinimumFractionDigits(0);
int days = numberFormat.parse(numberFormat.format(value)).intValue();

I hope it will be helpful.

我希望它会有所帮助。