ios - 弄错时差

Question

我不明白我在获取两个日期的正确差异时错在哪里，

-(void)updateTimeLabel{
    NSString *serverResponseTimeString = @"02-08-2014 05:26:32";
    NSString *systemDateString = @"02-08-2014 05:31:46";
    NSDate *serverTime = [self dateFromWebStringResponse:serverResponseTimeString];
    NSDate *systemDate = [self dateFromWebStringResponse:systemDateString];

    NSLog(@"serverResponseTime %@", serverResponseTimeString);
    NSLog(@"serverTime %@", serverTime);
    NSLog(@"systemDate %@", systemDate);
    NSLog(@"difference of time %d", [self differenceOfTimeInterval:systemDate toDate:serverTime]);
}

-(NSDate *)dateFromWebStringResponse:(NSString *)dateInString{
    NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
    [dateFormatter setDateFormat:@"mm-dd-yyyy hh:mm:ss"];
    NSDate *theDate = [dateFormatter dateFromString:dateInString];
    return theDate;
}


-(NSInteger)differenceOfTimeInterval:(NSDate *)fromDate toDate:(NSDate *)toDate{
    NSTimeInterval differenceOfIntervals = [toDate timeIntervalSinceDate: fromDate];
    NSInteger minutes = floor(differenceOfIntervals/60);
    return minutes;
}

输出:-

2014-02-08 17:58:57.185 iOSPractise[16770:907] serverResponseTime 02-08-2014 05:26:32
2014-02-08 17:58:57.186 iOSPractise[16770:907] serverTime 2014-01-07 23:56:32 +0000
2014-02-08 17:58:57.187 iOSPractise[16770:907] systemDate 2014-01-07 22:00:46 +0000
2014-02-08 17:58:57.188 iOSPractise[16770:907] difference of time 115 

我预计会有 5 分钟的差异。

Answer 1

您的日期格式有误。月份的格式是“MM”(不是“mm”，它是分钟)，24 小时格式是“HH”(“hh”代表 12 小时制的上午/下午):

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

此外，正如@Flexicoder 提到的，您应该指定一个独立于用户的区域设置:

[dateFormatter setLocale:[NSLocale localeWithLocaleIdentifier:@"en_US_POSIX"]];

(参见 http://www.flexicoder.com/blog/index.php/2013/10/ios-24-hour-date-format/ 或 What is the best way to deal with the NSDateFormatter locale "feechur"?。)