iOS 获取某年有几周，获取某年某周的日期范围-蒲公英云

iOS 获取某年有几周，获取某年某周的日期范围

//NSString转NSDate
+(NSDate *)dateFromString:(NSString *)dateString DateFormat:(NSString *)DateFormat{
    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
    [dateFormatter setDateFormat:DateFormat];
    NSDate *destDate= [dateFormatter dateFromString:dateString];
    return destDate;
}
//获取年月日对象
+(NSDateComponents *)getDateComponents:(NSDate *)date {
    NSCalendar *calendar = [NSCalendar currentCalendar];
//    [calendar setFirstWeekday:2]; //设置每周的开始是星期一
//    [calendar setMinimumDaysInFirstWeek:7]; //设置一周至少需要几天
    return [calendar components:
            NSYearCalendarUnit|
            NSMonthCalendarUnit|
            NSDayCalendarUnit|
            NSWeekOfYearCalendarUnit|
            NSQuarterCalendarUnit fromDate:date];
}
//获得某年的周数
+(NSInteger)getWeek_AccordingToYear:(NSInteger)year {
    NSDateComponents *comps = [DataTimeTool getDateComponents:[DataTimeTool dateFromString:[NSString stringWithFormat:@"%ld-12-31",year] DateFormat:@"yyyy-MM-dd"]];
    NSInteger week = [comps weekOfYear];
    if (week == 1) {
        return 52;
    }else {
        return week;
    }
}
/**
 *  获取某年某周的范围日期
 *
 *  @param year       年份
 *  @param weekofYear year里某个周
 *
 *  @return 时间范围字符串
 */
+(NSString*)getWeekRangeDate_Year:(NSInteger)year WeakOfYear:(NSInteger)weekofYear
{
    NSString *weekDate = @"";
    NSString *timeAxis = [NSString stringWithFormat:@"%ld-06-01 12:00:00",(long)year];
    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
    [dateFormatter setDateFormat:@"yyyy-MM-dd HH:mm:ss"];
    NSDate *date = [dateFormatter dateFromString:timeAxis];
    NSCalendar *calendar = [NSCalendar currentCalendar];
    /**这两个参数的设置影响着周次的个数和划分*****************/
    [calendar setFirstWeekday:2]; //设置每周的开始是星期一
//    [calendar setMinimumDaysInFirstWeek:7]; //设置一周至少需要几天
    NSDateComponents *comps = [calendar components:(NSCalendarUnitWeekOfYear | NSCalendarUnitWeekday | NSCalendarUnitWeekdayOrdinal | NSCalendarUnitYear | NSCalendarUnitMonth | NSCalendarUnitDay)
                                          fromDate:date];
    //时间轴是当前年的第几周
    NSInteger todayIsWeek = [comps weekOfYear];
    if ([DataTimeTool getWeek_AccordingToYear:year] == 53) {
        todayIsWeek += 1;
    }
    //获取时间轴是星期几 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 todayIsWeekDay = [comps weekday];
    // 计算当前日期和这周的星期一和星期天差的天数
    //firstDiff 星期一相差天数 、 lastDiff 星期天相差天数
    long firstDiff,lastDiff;
    if (todayIsWeekDay == 1) {
        firstDiff = -6;
        lastDiff = 0;
    }else
    {
        firstDiff = [calendar firstWeekday] - todayIsWeekDay;
        lastDiff = 8 - todayIsWeekDay;
    }
    NSDate *firstDayOfWeek= [NSDate dateWithTimeInterval:24*60*60*firstDiff sinceDate:date];
    NSDate *lastDayOfWeek= [NSDate dateWithTimeInterval:24*60*60*lastDiff sinceDate:date];
    long weekdifference = weekofYear - todayIsWeek;
    firstDayOfWeek= [NSDate dateWithTimeInterval:24*60*60*7*weekdifference sinceDate:firstDayOfWeek];
    lastDayOfWeek= [NSDate dateWithTimeInterval:24*60*60*7*weekdifference sinceDate:lastDayOfWeek];
    weekDate = [NSString stringWithFormat:@"(%@～%@)",[DataTimeTool stringFromDate:firstDayOfWeek DateFormat:@"y年M月d日"],[DataTimeTool stringFromDate:lastDayOfWeek DateFormat:@"y年M月d日"]];
    //weekDate = [NSString stringWithFormat:@"第%ld周(%@-%@)",weekofYear,[DataTimeTool stringFromDate:firstDayOfWeek DateFormat:@"yyyy年M月d号"],[DataTimeTool stringFromDate:lastDayOfWeek DateFormat:@"yyyy年M月d号"]];
    return weekDate;
}