Question

假设我在服务器@“2014-03-08T16：59 + 0000”中有这样的字符串。

NSCalendar *calendar = [NSCalendar currentCalendar];
NSDate *date = [self dateFromJSONString:@"2014-03-08T16:59+0000"];
NSDateComponents *dateComponents = [calendar components:(NSTimeZoneCalendarUnit) fromDate:date];

NSLog(@"TimeZone is %@", [[dateComponents timeZone] abbreviation]);

但TimeZone并非基于字符串，而是基于设备的currentTimeZone。

是否可以从字符串中提取timeZone？

Answer 1

您必须自己从字符串中解析GMT的偏移量。

这样的事情，但你必须调整你的略有不同的格式：

/**
 This is assuming format yyyy-MM-dd'T'HH:mm:ssZZZZZ . ie the last 5 chars are timezone offset from gtm in the form (+|-)##:##
 */
-(NSTimeZone*)timezoneFromDateString:(NSString*)dateString {
    NSTimeZone *timezone = nil;
    NSString *timezoneComponent = [dateString substringFromIndex:19];
    if(timezoneComponent.length == 6) {
        NSArray *components = [[timezoneComponent substringFromIndex:1] componentsSeparatedByString:@":"];
        NSInteger offset = [[timezoneComponent substringToIndex:1] isEqualToString:@"-"] ? -1 : 1;
        if(components.count == 2) {
            offset *= [components[0] integerValue] * 60*60 + [components[1] integerValue] *60;
            timezone =  [NSTimeZone timeZoneForSecondsFromGMT:offset];
        }
    }
    return timezone;
}

Answer 2

如果您确定需要解析的字符串始终以这种方式格式化，那么正则表达式提供了一种简单的方法：

NSString *str = @"2014-03-08T16:59+0000";

NSString *pattern = @"^.*T\\d{2}:\\d{2}";

NSString *timezone = [str stringByReplacingOccurrencesOfString: pattern
                                                    withString: @""
                                                       options: NSRegularExpressionSearch
                                                         range: NSMakeRange(0, str.length)];

Answer 3

-(NSArray*)convertToLocalDate:(NSString*)dateStr{
    NSArray *convert;

    NSString *time=@"";

    NSDateFormatter *dateFormatter1 = [[NSDateFormatter alloc] init];
    [dateFormatter1 setDateFormat:@"MM/dd/yyyy hh:mm:ss a"];
    NSDate *date = [dateFormatter1 dateFromString:dateStr];
    //NSLog(@"date : %@",date);

    NSTimeZone *currentTimeZone = [NSTimeZone localTimeZone];
    NSTimeZone *utcTimeZone = [NSTimeZone timeZoneWithAbbreviation:@"UTC"];

    NSInteger currentGMTOffset = [currentTimeZone secondsFromGMTForDate:date];
    NSInteger gmtOffset = [utcTimeZone secondsFromGMTForDate:date];
    NSTimeInterval gmtInterval = currentGMTOffset - gmtOffset;

    NSDate *destinationDate = [[NSDate alloc] initWithTimeInterval:gmtInterval sinceDate:date] ;

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


    [dateFormatters setDateFormat:@"dd.MM.yyyy"];

    [dateFormatters setTimeZone:[NSTimeZone systemTimeZone]];
    dateStr = [dateFormatters stringFromDate: destinationDate];

    NSDateFormatter *dateFormatters1 = [[NSDateFormatter alloc] init];
    [dateFormatters1 setDateFormat:@"hh:mm a"];


    [dateFormatters1 setTimeZone:[NSTimeZone systemTimeZone]];
    time = [dateFormatters1 stringFromDate: destinationDate];


    convert = [[NSArray alloc ]initWithObjects:dateStr,time,nil];
    return convert;
}

如何从字符串中获取NSTimeZone？

3 个答案: