Question

我有以下代码：

NSString *startDate = @"2014-09-29 05:46:34 +000";

// Format the string
NSRange range = NSMakeRange(0, 19);
startDate = [startDate substringWithRange:range];

NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:@"yyyy-MM-dd HH:mm:ss"];
NSDate *dateFromString = [[NSDate alloc] init];
dateFromString = [dateFormatter dateFromString:startDate];

NSDate *trendDate = [dateFromString dateByAddingTimeInterval:-3600*12];

NSString *dateString = [NSString stringWithFormat:@"%@", trendDate];

我的日期字符串最终结束为：

@"2014-09-29 00:46:34 +000";

为什么它只用了5个小时而不是12个小时？

Answer 1

不要从startDate字符串中获取子字符串，而是尝试以下日期格式：

dateFormatter.dateFormat = @"yyyy-MM-dd HH:mm:ss ZZZ"

然后

dateFromString = [dateFormatter dateFromString:startDate];

NSDate *trendDate = [dateFromString dateByAddingTimeInterval:-3600*12];

NSString *dateString = [dateFormatter stringFromDate:trendDate];

Answer 2

因为您要从日期字符串中删除时区错误日期

而不是从日期字符串中删除+000，只需替换日期格式。

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

用

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

删除代码

NSRange range = NSMakeRange(0, 19);
startDate = [startDate substringWithRange:range];

最终代码

NSString *startDate = @"2014-09-29 05:46:34 +000";

NSDateFormatter *dateFormatter = [[NSDateFormatter alloc] init];
[dateFormatter setDateFormat:@"yyyy-MM-dd HH:mm:ss ZZZ"];
NSDate *dateFromString = [[NSDate alloc] init];
dateFromString = [dateFormatter dateFromString:startDate];

NSDate *trendDate = [dateFromString dateByAddingTimeInterval:-(3600*12)];

减去并转换NSString和NSDate

2 个答案: