ios - 从日期字符串开始的 24 小时时间

Question

我正在尝试从以下字符串中以 24 小时格式获取时间和时间:

2015 年 7 月 2 日下午 2:30:00

这是我试过的:

-(NSString*)returnDate:(NSString*)dateString
{

    NSDateFormatter *dateFormatter1 = [[NSDateFormatter alloc] init];
    [dateFormatter1 setDateFormat:@"MM/dd/yyyy hh:mm:ss aaa"];
    NSDate *date = [dateFormatter1 dateFromString:dateString];

   dateString = [date descriptionWithLocale:[NSLocale systemLocale]];



    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:@"HH:mm a"];
    [dateFormatters setDateStyle:NSDateFormatterShortStyle];
    [dateFormatters setTimeStyle:NSDateFormatterShortStyle];
    [dateFormatters setDoesRelativeDateFormatting:YES];
    [dateFormatters setTimeZone:[NSTimeZone systemTimeZone]];
    dateString = [dateFormatters stringFromDate: destinationDate];

    return dateString;
}

输出:4:30

这是返回正确的时间，但采用 12 小时格式。我想要 24 小时格式的时间。

期望的输出:16:30

Answer 1

问题中有很多代码，试试这个:

NSString *dateString = @"7/2/2015 4:30:00 PM";

NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setTimeZone:[NSTimeZone systemTimeZone]];

[dateFormatter setDateFormat:@"MM/dd/yyyy hh:mm:ss aaa"];
NSDate *date = [dateFormatter dateFromString:dateString];

[dateFormatter setDateFormat:@"HH:mm"];
dateString = [dateFormatter stringFromDate: date];

NSLog(@"dateString: %@", dateString);

输出:

dateString: 16:30