Android 获取某月所有的日期和星期

有时候需要获取一个月的信息去展示数据，提供一些方法获取

private static List getWeekDay() {
    Calendar calendar = Calendar.getInstance();
    // 获取本周的第一天
    int firstDayOfWeek = calendar.getFirstDayOfWeek();
    List list = new ArrayList<>();
    for (int i = 0; i < 7; i++) {
        //Calendar.ERA          表示纪元
        //Calendar.MONTH        表示月
        //Calendar.DAY_OF_WEEK  表示星期几
        //Calendar.AM_PM        上午还是下午
        calendar.set(Calendar.DAY_OF_WEEK, firstDayOfWeek + i);
        WeekDay weekDay = new WeekDay();
        // 获取星期的显示名称，例如：周一、星期一、Monday等等
        //Calendar.SHORT得到的是诸如“周日”的名称，Calendar.LONG得到的是诸如“星期日”的名称
        //Locale.CHINA(中文)、Locale.ENGLISH(英文)等等。也可以使用Locale.getDefault()获取默认语言环境
        weekDay.week = calendar.getDisplayName(Calendar.DAY_OF_WEEK, Calendar.SHORT, Locale.ENGLISH);
        weekDay.month = new SimpleDateFormat("MM").format(calendar.getTime());
        weekDay.day = new SimpleDateFormat("dd").format(calendar.getTime());
        list.add(weekDay);
    }
    return list;
}

private static List getMonthDay() {
    Calendar calendar = Calendar.getInstance();
    //设置某一年
    calendar.set(Calendar.YEAR, 2023);
    //设置为某一个月
    calendar.set(Calendar.MONTH, getMonth() - 1);
    //本月第一天
    int firstDayOfMonth = calendar.getActualMinimum(Calendar.DAY_OF_MONTH);
    //本月最后一天
    int lastDayOfMonth = calendar.getActualMaximum(Calendar.DAY_OF_MONTH);
    List list = new ArrayList<>();
    for (int i = 0; i < lastDayOfMonth; i++) {
        calendar.set(Calendar.DAY_OF_MONTH, firstDayOfMonth + i);
        WeekDay weekDay = new WeekDay();
        // 获取星期的显示名称，例如：周一、星期一、Monday等等
        weekDay.week = calendar.getDisplayName(Calendar.DAY_OF_WEEK, Calendar.SHORT, Locale.getDefault());
        weekDay.month = new SimpleDateFormat("MM").format(calendar.getTime());
        weekDay.day = new SimpleDateFormat("dd").format(calendar.getTime());
        list.add(weekDay);
    }
    return list;
}

//获取当前月
public static int getMonth() {
    Calendar cd = Calendar.getInstance();
    //显示当前月份需要+1，因为是从0 开始计算的，使用时需要 -1 ，不然就是下个月份的日期了
    return cd.get(Calendar.MONTH) + 1;
}

private static class WeekDay {
    //星期的显示名称
    public String week;
    //对应的日期
    public String month;
    public String day;

    @Override
    public String toString() {
        return "WeekDay{" +
                "week='" + week + ''' +
                ", month='" + month + ''' +
                ", day='" + day + ''' +
                '}';
    }

}

打印一下：

List list = getMonthDay();
for (WeekDay weekday : list) {
    Log.e("--------------->", weekday.toString());
}