Calculate age from BirthDate

Question

I have DatePicker Dialog, When I select date at that time I want to calculate age it\'s working but when I select date of current year at that time it showing the -1 age instead

Answer 1

public static int getPerfectAgeInYears(int year, int month, int date) {

    Calendar dobCalendar = Calendar.getInstance();
    
    dobCalendar.set(Calendar.YEAR, year);
    dobCalendar.set(Calendar.MONTH, month);
    dobCalendar.set(Calendar.DATE, date);

    int ageInteger = 0;

    Calendar today = Calendar.getInstance();

    ageInteger = today.get(Calendar.YEAR) - dobCalendar.get(Calendar.YEAR);

    if (today.get(Calendar.MONTH) == dobCalendar.get(Calendar.MONTH)) {

        if (today.get(Calendar.DAY_OF_MONTH) < dobCalendar.get(Calendar.DAY_OF_MONTH)) {

            ageInteger = ageInteger - 1;
        }

    } else if (today.get(Calendar.MONTH) < dobCalendar.get(Calendar.MONTH)) {

        ageInteger = ageInteger - 1;

    }

    return ageInteger;
}

Consider Today's Date - 30th August 2020

If Birthdate - 29th July 1993, the output - 27

If Birthdate - 29th August 1993, the output - 27

If Birthdate - 30th August 1993, the output - 27

If Birthdate - 31st August 1993, the output - 26

If Birthdate - 31st September 1993, the output - 26

Answer 2

public String getAge(int year, int month, int day) {
        Calendar dob = Calendar.getInstance();
        Calendar today = Calendar.getInstance();

        dob.set(year, month-1, day);

        int age = today.get(Calendar.YEAR) - dob.get(Calendar.YEAR);

        if (today.get(Calendar.DAY_OF_YEAR) < dob.get(Calendar.DAY_OF_YEAR)) {
            age--;
        }

        Integer ageInt = new Integer(age);
        String ageS = ageInt.toString();

        return ageS;
    }

Answer 3

public int getAge(int year, int month, int day) {
    final Calendar birthDay = Calendar.getInstance();
    birthDay.set(year, month, day);
    final Calendar current = Calendar.getInstance();
    if (current.getTimeInMillis() < birthDay.getTimeInMillis())
        throw new IllegalArgumentException("age < 0");
    int age = current.get(Calendar.YEAR) - birthDay.get(Calendar.YEAR);
    if (birthDay.get(Calendar.MONTH) > current.get(Calendar.MONTH) ||
            (birthDay.get(Calendar.MONTH) == current.get(Calendar.MONTH) &&
                    birthDay.get(Calendar.DATE) > current.get(Calendar.DATE)))
        age--;
    return age;
}

Answer 4

static int calculateAge(int birthdayDay, int birthdayMonth, int birthdayYear)
{
    DateTime date = DateTime(birthdayYear, birthdayMonth, birthdayDay).toLocal();
    DateTime now = DateTime.now().toLocal();

    return now.difference(date).inDays ~/ 365.2425;
}

Answer 5

      private void calculateAge() {
    age.calcualteYear();
    age.calcualteMonth();
    age.calcualteDay();
    age.calculateMonths();
    age.calTotalWeeks();
    age.calTotalHours();
    age.calTotalMins();
    age.calTotalSecs();
    age.calTotalMilsecs();
    // Toast.makeText(getContext(), "click the resulted button"+age.getResult() , Toast.LENGTH_SHORT).show();
    result.setText("AGE (DD/MM/YY) :" + age.getResult());
}

after that create one class

 public class AgeCalculation {
private int startYear;
private int startMonth;
private int startDay;
private int endYear;
private int endMonth;
private int endDay;
private int resYear;
private int resMonth;
private int resDay;
private Calendar start;
private Calendar end;
public String getCurrentDate()
{
      end=Calendar.getInstance();
      endYear=end.get(Calendar.YEAR);
      endMonth=end.get(Calendar.MONTH);
      endMonth++;
      endDay=end.get(Calendar.DAY_OF_MONTH);
      return endDay+":"+endMonth+":"+endYear;
}
public void setDateOfBirth(int sYear, int sMonth, int sDay)
{
 startYear=sYear;
 startMonth=sMonth;
 startDay=sDay;

}
public void calcualteYear()
{
    resYear=endYear-startYear/(365);

}

public void calcualteMonth()
{
    if(endMonth>=startMonth)
    {
         resMonth= endMonth-startMonth;
    }
    else
    {
        resMonth=endMonth-startMonth;
        resMonth=12+resMonth;
        resYear--;
    }

}
public void  calcualteDay()
{

    if(endDay>=startDay)
    {
         resDay= endDay-startDay;
    }
    else
    {
        resDay=endDay-startDay;
        resDay=30+resDay;
        if(resMonth==0)
        {
            resMonth=11;
            resYear--;
        }
        else
        {
            resMonth--;
        }

    }
}

public String getResult()
{
    return resDay+":"+resMonth+":"+resYear;
}