IOS 获取某月的第一天和最后一天

//获取某月的第一天字符串

-(NSString *)getMonthFirstDayWithDate:(NSDate *)date format:(NSString *)aformat{

    NSDate * newDate = date;

    double interval = 0;

    NSDate * firstDate = nil;

    NSCalendar * calendar = [NSCalendar currentCalendar];

    BOOL bl = [calendar rangeOfUnit:NSCalendarUnitMonth startDate:&firstDate interval:&interval forDate:newDate];

    if(bl) {

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

        [myDateFormatter setDateFormat:aformat];

        NSString * firstString = [myDateFormatter stringFromDate: firstDate];

        return firstString;

    }

    return @"";

}

//获取某月的最后一天字符串

-(NSString *)getMonthLastDayWithDate:(NSDate *)date format:(NSString *)aformat{

    NSDate * newDate = date;

    double interval = 0;

    NSDate * firstDate = nil;

    NSDate * lastDate = nil;

    NSCalendar * calendar = [NSCalendar currentCalendar];

    BOOL bl = [calendar rangeOfUnit:NSCalendarUnitMonth startDate:&firstDate interval:&interval forDate:newDate];

    if(bl) {

        lastDate = [firstDate dateByAddingTimeInterval:interval -1];

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

        [myDateFormatter setDateFormat:aformat];

        NSString * lastString = [myDateFormatter stringFromDate:lastDate];

        return lastString;

    }

    return @"";

}

//调用某月第一天方法

[self getMonthFirstDayWithDate:[NSDate date] format:@"yyyy-MM-dd"];

//调用某月最后一天方法

[self getMonthLastDayWithDate:[NSDate date] format:@"yyyy-MM-dd"];