比较NSDate和[NSDate date] [英] Comparing an NSDate to [NSDate date]

问题描述

我想强制用户使用日期选择器选择日期。我明显使用compare：方法，但是，当我做以下代码，即使它是与[NSDate日期]相同的日期，它告诉执行if语句。这是我的代码：

  if（[datePicker.date compare：[NSDate date]] == NSOrderedAscending）// If the挑选的日期早于今天
 {
 UIAlertView * alert = [[UIAlertView alloc] initWithTitle：@嗯，这个日期早于今天
 message：@选择的时间早于今天的日期，请选择另一个
 delegate：nil 
 cancelButtonTitle：@好的，我会选择另一个
 otherButtonTitles：nil。 
 //显示提醒
 [alert show]; 
 
 //发布警报
 [alert release]; 
} 
  

解决方案

只要使用 UIDatePicker 的 minimumDate 属性，就可以解决问题，这甚至是一个更清洁的方法。

I am trying to force a user to select a date in the future with a date picker. I obviously used the compare: method, however, when I do the following code, even if it's the same date as [NSDate date], it tells the executes the if statement. Here is my code:

    if ([datePicker.date compare:[NSDate date]] == NSOrderedAscending) // If the picked date is earlier than today
{
    UIAlertView *alert = [[UIAlertView alloc] initWithTitle:@"Hmm, this date is earlier than today" 
                                                    message:@"The date you've selected is earlier than today's date, please pick another" 
                                                   delegate:nil  
                                          cancelButtonTitle:@"Okay, I'll pick another" 
                                          otherButtonTitles:nil];
    // Show the alert
    [alert show];

    // Release the alert
    [alert release];
}

解决方案

I don't know the answer to your problem, but how you could circumvent it.

Just use the minimumDate property of the UIDatePicker, that's even a much cleaner approach.

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