NSDate 根据今天的日期,推算出本周及本月是从几号到几号

一言不合,直接上代码:

1.根据当天的日期,推算出本周是从几号到几号

// 本天

            NSDate *date = [NSDate date];

            NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];

            [dateFormatter setDateFormat:@"YYYY-MM-dd"];

            NSString *Today = [dateFormatter stringFromDate:date];

// 本周的起止日期

    NSDate *now = [NSDate date];

            NSCalendar *calendar = [NSCalendar currentCalendar];

            NSDateComponents *comp = [calendar components:NSYearCalendarUnit|NSMonthCalendarUnit|NSDayCalendarUnit|NSWeekdayCalendarUnit|NSDayCalendarUnit

                                                 fromDate:now];

            

            // 得到星期几

            // 1(星期天) 2(星期一) 3(星期二) 4(星期三) 5(星期四) 6(星期五) 7(星期六)

            NSInteger weekDay = [comp weekday];

            // 得到几号

            NSInteger day = [comp day];

            

            DRNSLog(@"weekDay:%ld   day:%ld",weekDay,day);

            

            // 计算当前日期和这周的星期一和星期天差的天数

            long firstDiff,lastDiff;

            if (weekDay == 1) {

                firstDiff = 1;

                lastDiff = 0;

            }else{

                DRNSLog(@"%ld",[calendar firstWeekday]);

                firstDiff = [calendar firstWeekday] - weekDay + 1;

                lastDiff = 9 - weekDay - 1;

            }

            

            DRNSLog(@"firstDiff:%ld   lastDiff:%ld",firstDiff,lastDiff);

            

            // 在当前日期(去掉了时分秒)基础上加上差的天数

            NSDateComponents *firstDayComp = [calendar components:NSYearCalendarUnit|NSMonthCalendarUnit|NSDayCalendarUnit fromDate:now];

            [firstDayComp setDay:day + firstDiff];

            NSDate *firstDayOfWeek= [calendar dateFromComponents:firstDayComp];

            

            NSDateComponents *lastDayComp = [calendar components:NSYearCalendarUnit|NSMonthCalendarUnit|NSDayCalendarUnit fromDate:now];

            [lastDayComp setDay:day + lastDiff];

            NSDate *lastDayOfWeek= [calendar dateFromComponents:lastDayComp];

            

            NSDateFormatter *formater = [[NSDateFormatter alloc] init];

//            [formater setDateFormat:@"yyyy-MM-dd HH:mm:ss"];

            [formater setDateFormat:@"yyyy-MM-dd"];

            DRNSLog(@"星期一开始 %@",[formater stringFromDate:firstDayOfWeek]);

            DRNSLog(@"当前 %@",[formater stringFromDate:now]);

            DRNSLog(@"星期天结束 %@",[formater stringFromDate:lastDayOfWeek]);

// 

2.推算出本月的起止日期

            NSDate *now = [NSDate date];

            NSCalendar *calendar = [NSCalendar currentCalendar];

            NSDateComponents *comp = [calendar components:NSYearCalendarUnit|NSMonthCalendarUnit|NSDayCalendarUnit|NSWeekdayCalendarUnit|NSDayCalendarUnit

                                                 fromDate:now];

            // 得到星期几

            // 1(星期天) 2(星期一) 3(星期二) 4(星期三) 5(星期四) 6(星期五) 7(星期六)

//            NSInteger weekDay = [comp weekday];

            // 得到几号

            NSInteger day = [comp day];

            

            NSInteger month = [comp month];

            DRNSLog(@"month:%ld   day:%ld",month,day);

            

            NSDateComponents *firstDayComp = [calendar components:NSYearCalendarUnit|NSMonthCalendarUnit|NSDayCalendarUnit fromDate:now];

            [firstDayComp setDay:1];

            NSDate *firstDayOfWeek= [calendar dateFromComponents:firstDayComp];

            

            NSRange range = [calendar rangeOfUnit:NSDayCalendarUnit inUnit:NSMonthCalendarUnit forDate:now];

            NSDateComponents *lastDayComp = [calendar components:NSYearCalendarUnit|NSMonthCalendarUnit|NSDayCalendarUnit fromDate:now];

            [lastDayComp setDay:range.length];

            NSDate *lastDayOfWeek= [calendar dateFromComponents:lastDayComp];

            

            NSDateFormatter *formater = [[NSDateFormatter alloc] init];

            //            [formater setDateFormat:@"yyyy-MM-dd HH:mm:ss"];

            [formater setDateFormat:@"yyyy-MM-dd"];

            

            startdate = [formater stringFromDate:firstDayOfWeek];

            enddate = [formater stringFromDate:lastDayOfWeek];

            [self loadData1];