iOS获取周一至周末对应日期

firstWeekday 值为1，可以自己设置
weekDay 为 1 时对应的是周日

- (NSString *)getWeekTime
{
    NSDate *nowDate = [NSDate date];
    NSCalendar *calendar = [NSCalendar currentCalendar];
    NSDateComponents *comp = [calendar components:NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay | NSCalendarUnitWeekday  fromDate:nowDate];
    // 获取今天是周几
    NSInteger weekDay = [comp weekday];
    // 获取几天是几号
    NSInteger day = [comp day];
    NSLog(@"%ld----%ld",(long)weekDay,(long)day);

    // 计算当前日期和本周的星期一和星期天相差天数
    long firstDiff,lastDiff;
    //    weekDay = 1; weekDay == 1 == 周日
    if (weekDay == 1)
    {
        firstDiff = -6;
        lastDiff = 0;
    }
    else
    {
        firstDiff = [calendar firstWeekday] - weekDay + 1;
        lastDiff = 8 - weekDay;
    }
    NSLog(@"firstDiff: %ld   lastDiff: %ld",firstDiff,lastDiff);
    
    // 在当前日期(去掉时分秒)基础上加上差的天数
    NSDateComponents *baseDayComp = [calendar components:NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay  fromDate:nowDate];

    //获取周一日期
    [baseDayComp setDay:day + firstDiff];
    NSDate *firstDayOfWeek = [calendar dateFromComponents:baseDayComp];
    
    //获取周末日期
    [baseDayComp setDay:day + lastDiff];
    NSDate *lastDayOfWeek = [calendar dateFromComponents:baseDayComp];
    
    NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
    [formatter setDateFormat:@"YYYY年MM月dd日"];
    NSString *firstDay = [formatter stringFromDate:firstDayOfWeek];
    NSString *lastDay = [formatter stringFromDate:lastDayOfWeek];
    NSLog(@"%@=======%@",firstDay,lastDay);
    
    NSString *dateStr = [NSString stringWithFormat:@"%@-%@",firstDay,lastDay];
    
    return dateStr;
    
}