设置星期几的第一天到星期一，在android中使用日历时，获取星期一的日期不正确

Question

我试着让星期一的日期使用下面的代码（今天是2016/5/6）

Calendar calendar1 = Calendar.getInstance();
calendar1.setFirstDayOfWeek(Calendar.MONDAY);
calendar1.set(Calendar.DAY_OF_WEEK, Calendar.MONDAY);
calendar1.getTime();

但结果是2016/4/25 ，结果应该是2016/5/2 ，而且似乎在5月错了

它在下面工作正确

Calendar calendar1 = Calendar.getInstance();
calendar1.setFirstDayOfWeek(Calendar.MONDAY);
calendar1.setTime(new Date());
calendar1.set(Calendar.DAY_OF_WEEK, Calendar.MONDAY);
calendar1.getTime();

但是当我尝试下面

  public static Calendar createCalendar(Date date, int firstDayOfWeek) {
    Calendar calendar = Calendar.getInstance();
    if (date == null) return calendar;
    calendar.setFirstDayOfWeek(firstDayOfWeek);
    calendar.setTime(date);
    return calendar;
  }

  public static Calendar[] getWeekStartEnd(Date date) {
    Calendar[] calendars = new Calendar[2];
    Calendar calendar = createCalendar(date, Calendar.MONDAY);
    Calendar tempCalendar1 = createCalendar(date, Calendar.MONDAY);

    calendar.set(Calendar.DAY_OF_WEEK, Calendar.MONDAY);
    tempCalendar1.set(Calendar.DAY_OF_WEEK, Calendar.MONDAY);

    calendars[0] = calendar;
    calendars[1] = tempCalendar1;
    return calendars;
  }

它仍然无法正常工作我想知道原因

Answer 1

您可能需要当前周的第一天（假设当前日期==> 2016/5/5，因此您可能需要第一天==> 2016/5/2，即周一）

Calendar calendar = Calendar.getInstance();
// get device day
SimpleDateFormat formatter = new SimpleDateFormat("EEE");
String devicedaystring = formatter.format(calendar.getTime());
//get Device date
SimpleDateFormat f = new SimpleDateFormat("yyyy-MM-dd");
String devicedatestring = f.format(calendar.getTime());

String current_date = checkday(devicedatestring, devicedaystring);
// To Convert String date to Date object
SimpleDateFormat f1 = new SimpleDateFormat("yyyy-MM-dd");
Date date = f1.parse( current_date);

private String checkDay(String date, String day)
    {
        if(day.equalsIgnoreCase("MON"))
        {
            return date;
        }
        else
        {
            SimpleDateFormat f = new SimpleDateFormat("yyyy-MM-dd");
            String[] ss=date.split("-");
            int yy = Integer.parseInt(ss[0]);
            int MM = Integer.parseInt(ss[1]);
            int dd = Integer.parseInt(ss[2]);
            Calendar calendar = Calendar.getInstance();
            calendar.set(yy,MM-1,dd);
            calendar.set(Calendar.DAY_OF_WEEK, Calendar.MONDAY);
            date =  f.format(calendar.getTime());
            Logger.showVerboesLog("~~~", "First Day of Week ===  " +date);
            return date;
        }
    }

Answer 2

尝试这个：

 Calendar calendar1 = Calendar.getInstance();
                calendar1.setFirstDayOfWeek(Calendar.MONDAY);
                calendar1.set(Calendar.DAY_OF_WEEK, Calendar.MONDAY);
                calendar1.setTime(new Date());
                calendar1.set(Calendar.DAY_OF_WEEK, Calendar.MONDAY);
                calendar1.getTime();