-(NSString *)dateTimeDifferenceWithStartTime:(NSString *)startTime endTime:(NSString *)endTime{
NSDateFormatter *date = [[NSDateFormatter alloc]init];
[date setDateFormat:@"yyyy-MM-dd HH:mm:ss"];
NSDate *startD =[date dateFromString:startTime];
NSDate *endD = [date dateFromString:endTime];
NSTimeInterval start = [startD timeIntervalSince1970]*1;
NSTimeInterval end = [endD timeIntervalSince1970]*1;
NSTimeInterval value = end - start;
int second = (int)value %60;//秒
int minute = (int)value /60%60;
int house = (int)value % (24 * 3600)/3600;
int day = (int)value / (24 * 3600);
NSString *str;
if (day != 0) {
str = [NSString stringWithFormat:@"倒计时: %d天%d小时%d分",day,house,minute];
}else if (day==0 && house != 0) {
str = [NSString stringWithFormat:@"倒计时: %d天%d小时%d分",day,house,minute];
}else if (day== 0 && house== 0 && minute!=0) {
str = [NSString stringWithFormat:@"倒计时: %d天%d小时%d分",day,house,minute];
}else{
if (second == 0) {
NSString *time = [NSString stringWithFormat:@"倒计时：0天0小时0分"];
}
// str = [NSString stringWithFormat:@"耗时%d秒",second];
}
if(day<=0 && minute<=0 &&house<=0){
}
return str;
}
