IOS-時間戳轉化時間

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

    [formatter setDateStyle:NSDateFormatterMediumStyle];

    [formatter setTimeStyle:NSDateFormatterShortStyle];

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

    

    NSDate *date = [formatter dateFromString:_dataArray.publishertime];

    NSTimeInterval late = [date timeIntervalSince1970]*1;

    

    NSString *timeString = nil;

    NSDate *dates = [NSDate date];

    NSTimeInterval now = [dates timeIntervalSince1970]*1;

    NSTimeInterval cha = now - late;

    if (cha/3600<1) {  //一小時3600秒

        timeString = [NSString stringWithFormat:@"%f",cha/60];

        timeString = [timeString substringToIndex:timeString.length-7];  //外國和中國時差7小時

        timeString = [NSString stringWithFormat:@"%@分鐘前",timeString];

        _releaseTimeLabel.text = [NSString stringWithFormat:@"%@",timeString];

    }

    

    if (cha/3600 >1 && cha/86400 <1) {

        timeString = [NSString stringWithFormat:@"%f",cha/3600];

        timeString = [timeString substringToIndex:timeString.length-7];

        timeString = [NSString stringWithFormat:@"%@小時前",timeString];

       _releaseTimeLabel.text = [NSString stringWithFormat:@"%@",timeString];

    }

    if (cha/86400 >1) {

        timeString = [NSString stringWithFormat:@"%f",cha/86400];

        timeString = [timeString substringToIndex:timeString.length-7];

        int num = [timeString intValue];

        if (num <2) {

            timeString = [NSString stringWithFormat:@"昨天"];

            

            _releaseTimeLabel.text = [NSString stringWithFormat:@"%@",timeString];

        }else if (num ==2 ){

            timeString = [NSString stringWithFormat:@"前天"];

            

            _releaseTimeLabel.text = [NSString stringWithFormat:@"%@",timeString];

        }else if (num >2 ){

            timeString = [NSString stringWithFormat:@"%@天前",timeString];

            

            _releaseTimeLabel.text = [NSString stringWithFormat:@"%@",timeString];

        }

    }