寫一個方法如下：

public String getOurSelWeek(int sel) {        Date date = null;        String[] weekDaysName = {"周日", "周一", "周二", "周三", "周四", "周五", "周六"};        SimpleDateFormat df = new SimpleDateFormat("yyy-MM-dd HH:mm:ss");        Calendar calendar = Calendar.getInstance();        calendar.roll(Calendar.DAY_OF_YEAR, sel);        String str = df.format(calendar.getTime());        try {            date = df.parse(str);        } catch (ParseException e) {            e.PRintStackTrace();        }        calendar.setTime(date);        int intWeek = calendar.get(Calendar.DAY_OF_WEEK) - 1;        return weekDaysName[intWeek];    }
然后在需要展示的布局處 調用該方法
tv_week.setText(xxxActivity.this.getOurSelWeek(1));
設置成功之后即能顯示