获取当前小时的前几个小时(类别)

获取当前小时的前几个小时(类别)

+ (NSDate *)df_currentHourWithBeforeHours:(NSInteger)dHours
{
    NSTimeInterval aTimeInterval = [[NSDate date] timeIntervalSinceReferenceDate] - 3600 * dHours;
    NSDate *newDate = [NSDate dateWithTimeIntervalSinceReferenceDate:aTimeInterval];
    return newDate;
}