Objective-C 如何将日期字符串转换为另一种格式

Question

我有一个日期选择器，它只为那个日期添加日期我想添加时间字符串并将其转换为日期。

fromString = @"00:00:00";
NSString *fromDate = [fromdate.text stringByAppendingString:@" "];
fromDate = [fromDate fromString];
NSDate *currentDate = [self dateFromString:fromDate withFormat:@"dd/MM/yyyy HH:mm:ss"];
NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:@"dd/MM/yyyy HH:mm:ss"];
[dateFormatter setTimeZone:[NSTimeZone timeZoneWithName:@"GMT+5.30"]];
NSString *dateString = [dateFormatter stringFromDate: currentDate];
NSDateFormatter *formatter = [[NSDateFormatter alloc] init];
NSDate *date = [self dateFromString: dateString withFormat:@"dd/MM/yyyy HH:mm:ss"];
NSString *fromDate1 = [NSString stringWithFormat:@"/Date(%.0f000%@)/", [date timeIntervalSince1970],[formatter stringFromDate:date]];

我的问题是我在转换为字符串时获得了 5.30 的额外时间。

Answer 1

NSString *finalDate = ……

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

NSLocale *location = [NSLocale currentLocale];

NSString *country = [location localeIdentifier];

NSLocale *locale = [[NSLocale alloc] initWithLocaleIdentifier:country];

[dateFormatterTime setLocale:locale];

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

NSDate *timeZone = [dateFormatterTime dateFromString:finalDate];

[dateFormatterTime setDateFormat:@"yyyy-MM-dd hh:mm:ss a"];

NSTimeZone *currentTimeZone = [NSTimeZone localTimeZone];

NSTimeZone *utcTimeZone = [NSTimeZone timeZoneWithAbbreviation:@"EST"]; // set as you wish

NSInteger currentGMTOffset = [currentTimeZone secondsFromGMTForDate:timeZone];

NSInteger gmtOffset = [utcTimeZone secondsFromGMTForDate:timeZone];

NSTimeInterval gmtInterval = currentGMTOffset - gmtOffset;

// get final date in LocalTimeZone
NSDate *destinationDate = [[NSDate alloc] initWithTimeInterval:gmtInterval sinceDate:timeZone];

NSLog(@“你的 NSDate = %@”, destinationDate);

Answer 2

My Problem is that I'm getting 5.30 extra time when converting to string.

要从最初使用的字符串转换：

NSDate *CurrentDate = [self dateFromString:fROMDATE withFormat:@"dd/MM/yyyy HH:mm:ss"];

您没有提供 dateFromString 的代码，但猜测此例程使用 GMT/UTC 时区进行转换。

要转换回您首先执行的字符串：

[DATEFORMATER setTimeZone:[NSTimeZone timeZoneWithName:@"GMT+5.30"]];

因此，如果您的原始时间是从字符串转换为 GMT，您的 DATE_STRING 将显示 5.5 小时的时间 "later"（与 GMT 相同的时间点，只是显示在GMT+5.30 时区）。

HTH

Objective-C 如何将日期字符串转换为另一种格式

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