好吧,我想这个问题已经被问过一千次了,但由于某种原因,答案并没有真正起作用或有其他问题,......
无论如何,这就是我的“工作”:
NSCalendar *calendar = [NSCalendar currentCalendar];
NSDate *currentDate = [NSDate date];
NSDateComponents *comps = [[NSDateComponents alloc] init];
// set tomorrow (0: today, -1: yesterday)
[comps setDay:0];
NSDate *dateToday = [calendar dateByAddingComponents:comps toDate:currentDate options:0];
[comps setDay:-1];
NSDate *dateYesterday = [calendar dateByAddingComponents:comps toDate:currentDate options:0];
[comps release];
NSString *todayString = [self.dateFormatter stringFromDate:dateToday] ;
NSString *yesterdayString = [self.dateFormatter stringFromDate:dateYesterday] ;
NSString *refDateString = [self.dateFormatter stringFromDate:info.date];
if ([refDateString isEqualToString:todayString])
{
cell.title.text = @"Today";
} else if ([refDateString isEqualToString:yesterdayString])
{
cell.title.text = @"Yesterday";
} else
{
cell.title.text = [self.dateFormatter stringFromDate:info.date];
}
现在解决问题:
这似乎只是日期比较的大量代码,有更简单的方法吗?
最重要的问题是所有对象的释放。正如您可能已经猜到的,我在 UITableViewController 中使用了它。我的代码中也有这些行:
//[calendar release];
//[currentDate release];
//[dateToday release];
//[dateYesterday release];
//[todayString release];
//[yesterdayString release];
//[refDateString release];
问题是,一旦我取消注释其中一行,我的应用程序就会崩溃,我不知道为什么?!希望有人能在这里启发我。
非常感谢。
最佳答案
最简单的方法就是比较日期的描述
:
// Your dates:
NSDate * today = [NSDate date];
NSDate * yesterday = [NSDate dateWithTimeIntervalSinceNow:-86400]; //86400 is the seconds in a day
NSDate * refDate; // your reference date
// 10 first characters of description is the calendar date:
NSString * todayString = [[today description] substringToIndex:10];
NSString * yesterdayString = [[yesterday description] substringToIndex:10];
NSString * refDateString = [[refDate description] substringToIndex:10];
if ([refDateString isEqualToString:todayString])
{
cell.title.text = @"Today";
} else if ([refDateString isEqualToString:yesterdayString])
{
cell.title.text = @"Yesterday";
} else
{
cell.title.text = refDateString;
}
如果您想更改日期字符串的格式,可以使用 descriptionWithLocale:
代替。
关于iphone - 比较今天或昨天的 NSDate,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/2893835/