如何在Objective-C中增加NSDate对象 [英] How do I Increment an NSDate object in Objective-C

问题描述

我想输入当前日期作为第二天我使用的代码如下

I want to take the next day by giving the current date The code i used as follows

+(NSDate *)getForDays:(int)days fromDate:(NSDate *) date {
    NSTimeInterval secondsPerDay = 24 * 60 * 60 * days;
        return [date addTimeInterval:secondsPerDay];
} 

这可以正常工作，但是启用夏令时会导致错误.启用夏时制时，我该如何工作.

this works fine but when the daylight saving enabled this leads to errors. How can I make this work when daylight saving is enabled.

推荐答案

您已经发现，现在所拥有的内容很容易出错.它不仅会因夏令时变更而跳闸，而且如果您的用户使用非公历会怎样呢?然后，几天就不会24小时长了.

As you have found, what you have now is pretty error-prone. Not only can it trip up over a daylight savings change, but also what if your user has a non-gregorian calendar? Then, days are not 24 hours long.

相反，使用为此专门设计的 NSCalendar 和 NSDateComponents :

Instead, use NSCalendar and NSDateComponents which were exactly designed for this:

+ (NSDate *)getForDays:(int)days fromDate:(NSDate *)date
{
    NSDateComponents *components= [[NSDateComponents alloc] init];
    [components setDay:days];

    NSCalendar *calendar = [NSCalendar currentCalendar];
    return [calendar dateByAddingComponents:components toDate:date options:0];
}

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