方式一 后臺給的格式為yyyy-MM-dd HH:mm:ss.SSS

• 上代碼

+ (NSString *) compareCurrentTime:(NSString *)str
{
    
    //把字符串轉為NSdate
    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
    [dateFormatter setDateFormat:@"yyyy-MM-dd HH:mm:ss.SSS"];
    NSDate *timeDate = [dateFormatter dateFromString:str];
    
    //得到與當前時間差
    NSTimeInterval  timeInterval = [timeDate timeIntervalSinceNow];
    timeInterval = -timeInterval;
    //標準時間和北京時間差8個小時
    timeInterval = timeInterval - 8*60*60;
    long temp = 0;
    NSString *result;
    if (timeInterval < 60) {
        result = [NSString stringWithFormat:@"剛剛"];
    }
    else if((temp = timeInterval/60) <60){
        result = [NSString stringWithFormat:@"%d分鐘前",temp];
    }
    
    else if((temp = temp/60) <24){
        result = [NSString stringWithFormat:@"%d小時前",temp];
    }
    
    else if((temp = temp/24) <30){
        result = [NSString stringWithFormat:@"%d天前",temp];
    }
    
    else if((temp = temp/30) <12){
        result = [NSString stringWithFormat:@"%d月前",temp];
    }
    else{
        temp = temp/12;
        result = [NSString stringWithFormat:@"%d年前",temp];
    }
    
    return  result;
}

方式二 后臺給的格式為 純數字1352170595000(13位)

• 上代碼

/** 通過行數, 返回更新時間 */
- (NSString *)updateTimeForRow:(NSInteger)row {
    // 獲取當前時時間戳 1466386762.345715 十位整數 6位小數
    NSTimeInterval currentTime = [[NSDate date] timeIntervalSince1970];
    // 創建歌曲時間戳(后臺返回的時間 一般是13位數字)
     NSTimeInterval createTime = self.model.tracks.list[row].createdAt/1000;
    // 時間差
    NSTimeInterval time = currentTime - createTime;
    
    // 秒轉小時
    NSInteger hours = time/3600;
    if (hours<24) {
        return [NSString stringWithFormat:@"%ld小時前",hours];
    }
    //秒轉天數
    NSInteger days = time/3600/24;
    if (days < 30) {
        return [NSString stringWithFormat:@"%ld天前",days];
    }
    //秒轉月
    NSInteger months = time/3600/24/30;
    if (months < 12) {
        return [NSString stringWithFormat:@"%ld月前",months];
    }
    //秒轉年
    NSInteger years = time/3600/24/30/12;
    return [NSString stringWithFormat:@"%ld年前",years];
}