objective-c - 如何在 Objective-C 中比较两个日期

Question

我有两个日期:2009-05-11 和当前日期。我想检查给定日期是否为当前日期。这怎么可能。

Answer 1

Cocoa has couple of methods for this :

在 NSDate 中

– isEqualToDate:  
– earlierDate:  
– laterDate:  
– compare:

当你使用 - (NSComparisonResult)compare:(NSDate *)anotherDate 时，你会得到其中之一:

The receiver and anotherDate are exactly equal to each other, NSOrderedSame
The receiver is later in time than anotherDate, NSOrderedDescending
The receiver is earlier in time than anotherDate, NSOrderedAscending.

例子:

NSDate * now = [NSDate date];
NSDate * mile = [[NSDate alloc] initWithString:@"2001-03-24 10:45:32 +0600"];
NSComparisonResult result = [now compare:mile];

NSLog(@"%@", now);
NSLog(@"%@", mile);

switch (result)
{
    case NSOrderedAscending: NSLog(@"%@ is in future from %@", mile, now); break;
    case NSOrderedDescending: NSLog(@"%@ is in past from %@", mile, now); break;
    case NSOrderedSame: NSLog(@"%@ is the same as %@", mile, now); break;
    default: NSLog(@"erorr dates %@, %@", mile, now); break;
}

[mile release];