Question

我有一个CalendarView，允许用户选择日期并输入活动。

每当更改所选日期时，我都会调用一个方法：

private void selectedDateChanged(CalendarView view, int year, int month, int dayOfMonth){
        //note: _Calendar is set to the view when activity loads hence the
        //the reason for not using view.getDate();
        Long timeSinceEpoch = _Calendar.getDate();

        GregorianCalendar calendar = new GregorianCalendar();
        calendar.setTimeInMillis(timeSinceEpoch);

        System.out.println(String.format("With gregorian calendar \n Day: %s \n Month: %s \n Year: %s",
                calendar.DAY_OF_MONTH, calendar.MONTH, calendar.YEAR));

    }

每次选择的日期发生变化时都会调用该方法，问题是每次调用该方法时GregorianCalendar都不会更新。每当我选择新的一天时，

I/System.out: With gregorian calendar 
I/System.out:  Day: 5 
I/System.out:  Month: 2 
I/System.out:  Year: 1

打印出

，并且在选择新日期时不会更新。

我无法弄清楚如何强制GregorianCalendar更新，CalendarView的javadoc说getDate（）应该返回当前选择的日期（以毫秒为单位），因为unix epoch

Answer 1

System.out.println(String.format("With gregorian calendar \n Day: %s \n Month: %s \n Year: %s",
            dayOfMonth, month, year));

Answer 2

事实证明Calendar.DAY_OF_MONTH，Calendar.MONTH和CALENDAR.YEAR不是包含该信息的字段，而是表示您在调用Calendar.get();时要查找的内容的整数

所以解决这个问题非常简单，我了解到，正确的代码是：

private void selectedDateChanged(CalendarView view, int year, int month, int dayOfMonth){
        //note: _Calendar is set to the view when activity loads hence the
        //the reason for not using view.getDate();
        Long timeSinceEpoch = _Calendar.getDate();

        GregorianCalendar calendar = new GregorianCalendar();
        calendar.setTimeInMillis(timeSinceEpoch);

        //Notice instead of calling cal.DAY_OF_MONTH directly
        //I now call calendar.get(Calendar.DAY_OF_MONTH)
        System.out.println(String.format("With gregorian calendar \n Day: %s \n Month: %s \n Year: %s",
                calendar.get(Calendar.DAY_OF_MONTH), calendar.get(Calendar.MONTH), calendar.get(Calendar.YEAR)));

    }

Java Android CalendarView selectedDateChanged没有更新

2 个答案: