NsDate格式化程序从String给出错误的日期

Question

我有以下代码,它采用NSString并返回NSDate.我已经从一个完全正常运行的项目中复制了这个代码 - 但是有些如何给出错误的输出

- (NSDate *)dateFromString:(NSString *)date
{
    static NSDateFormatter *dateFormatter;
    if (!dateFormatter)
    {
        dateFormatter = [[NSDateFormatter alloc] init];
        [dateFormatter setDateFormat:@"dd-MM-yyyy"];
    }

    NSLog(@"Date: %@ Formatted: %@",date,[dateFormatter dateFromString:date]);

    return [dateFormatter dateFromString:date];
}

输出来自日志:

Date: 07-01-2014 Formatted: 2014-01-06 18:30:00 +0000
Date: 24-01-2014 Formatted: 2014-01-23 18:30:00 +0000
Date: 06-01-2014 Formatted: 2014-01-05 18:30:00 +0000
Date: 15-01-2014 Formatted: 2014-01-14 18:30:00 +0000
Date: 22-01-2014 Formatted: 2014-01-21 18:30:00 +0000
Date: 31-01-2014 Formatted: 2014-01-30 18:30:00 +0000
Date: 14-01-2014 Formatted: 2014-01-13 18:30:00 +0000
Date: 30-01-2014 Formatted: 2014-01-29 18:30:00 +0000

奇怪的是,它也在改变日期.. !! 任何帮助...... !!!

Answer 1

结果是格林威治标准时间输出结果 - 即如果您距格林威治标准时间5:3小时.

如果希望在该时区中返回格式化日期,则需要指定时区:(这是+0000的含义)

- (NSDate *)dateFromString:(NSString *)date
{
    static NSDateFormatter *dateFormatter;
    if (!dateFormatter)
    {
        dateFormatter = [[NSDateFormatter alloc] init];
        [dateFormatter setLocale:[[NSLocale alloc] initWithLocaleIdentifier:@"en_US_POSIX"]];
        [dateFormatter setTimeZone:[NSTimeZone timeZoneForSecondsFromGMT:0]];
        [dateFormatter setDateFormat:@"dd-MM-yyyy"];
    }

    NSLog(@"Date: %@ Formatted: %@",date,[dateFormatter dateFromString:date]);

    return [dateFormatter dateFromString:date];
}