iOS 显示时间（几分钟前，几小时前，几天前）

+ (NSString *) compareCurrentTime:(NSString *)str

{

//把字符串转为NSdate

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

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

NSDate *timeDate = [dateFormatter dateFromString:str];

NSDate *currentDate = [NSDate date];

NSTimeInterval timeInterval = [currentDate timeIntervalSinceDate:timeDate];

long temp = 0;

NSString *result;

if (timeInterval/60 < 1) {

result = [NSString stringWithFormat:@"刚刚"];

}

else if((temp = timeInterval/60) <60){

result = [NSString stringWithFormat:@"%ld分钟前",temp];

}

else if((temp = temp/60) <24){

result = [NSString stringWithFormat:@"%ld小时前",temp];

}

else if((temp = temp/24) <30){

result = [NSString stringWithFormat:@"%ld天前",temp];

}

else if((temp = temp/30) <12){

result = [NSString stringWithFormat:@"%ld月前",temp];

}

else{

temp = temp/12;

result = [NSString stringWithFormat:@"%ld年前",temp];

}

return  result;

}