如何比较两个日期，返回天数答案

【问题标题】：How can I compare two dates, return a number of days如何比较两个日期，返回天数
【发布时间】：2011-02-02 15:07:29
【问题描述】：

如何比较两个日期返回天数。例如：缺席 X 天的杯赛。看看我的代码。

  NSDateFormatter *df = [[NSDateFormatter alloc]init];  
  [df setDateFormat:@"d MMMM,yyyy"];  
  NSDate *date1 = [df dateFromString:@"11-05-2010"];  
  NSDate *date2 = [df dateFromString:@"11-06-2010"];  
  NSTimeInterval interval = [date2 timeIntervalSinceDate:date1];  
  //int days = (int)interval / 30;  
  //int months = (interval - (months/30)) / 30;  
  NSString *timeDiff = [NSString stringWithFormat:@"%dMissing%d days of the Cup",date1,date2, fabs(interval)];  

  label.text = timeDiff; // output (Missing X days of the Cup)

【问题讨论】：

你可以查看这个答案stackoverflow.com/questions/13236719/…它帮助解决了我的问题

标签： objective-c compare days

【解决方案1】：

试试这个类别：

@interface NSDate (DateUtils)

-(NSInteger)numberOfDaysUntilDay:(NSDate *)aDate; 

@end

@implementation NSDate (DateUtils)

-(NSInteger)numberOfDaysUntilDay:(NSDate *)aDate
{

    NSCalendar *calendar = [[NSCalendar alloc]
                             initWithCalendarIdentifier:NSCalendarIdentifierGregorian];

    NSDateComponents *components = [calendar components:NSCalendarUnitDay
                                                fromDate:self
                                                  toDate:aDate options:kNilOptions];

    return [components day];

}

@end

您可以通过添加导入来使用此类别：

#import "NSDate+DateUtils.h"

并从您的代码中调用它：

NSInteger days = [myDate numberOfDaysUntilDay:someOtherDate];

【讨论】：

【解决方案2】：

需要调用此方法并设置 2 个我们想要以不同方式计算的日期。

-(void) calculateSleepHours:(NSDate *)sleepDate :(NSDate *)wakeStr 
{

   if (sleepDate !=nil && wakeStr!=nil) {`enter code here`

    NSDateFormatter *dateFormatter1 = [[NSDateFormatter alloc] init];
    [dateFormatter1 setDateFormat:@"yyyy-MM-dd HH:mm:ssZ"];
    NSDate *date1 = [ApplicationManager getInstance].sleepTime;;

    NSDate *date2 = [ApplicationManager getInstance].wakeupTime;

    NSCalendar *gregorian = [[NSCalendar alloc]
                             initWithCalendarIdentifier:NSGregorianCalendar];

    NSUInteger unitFlags = NSMonthCalendarUnit | NSDayCalendarUnit|NSHourCalendarUnit|NSMinuteCalendarUnit|NSSecondCalendarUnit;

    NSDateComponents *components = [gregorian components:unitFlags
                                                fromDate:date1
                                                  toDate:date2 options:0];

    NSInteger months = [components month];
    NSInteger days = [components day];
    NSInteger hours = [components hour];
    NSInteger minute=[components minute];
    NSInteger second=[components second];
    DLog(@"Month %ld day %ld hour is %ld min %ld sec %ld  ",(long)months,(long)days,(long)hours,(long)minute,(long)second);

    sleepHours.text=[NSString stringWithFormat:@"Hour %ld Min %ld Sec %ld",(long)hours,(long)minute,(long)second];
    }
}

【讨论】：

【解决方案3】：

您可以使用下一个类别：

@interface NSDate (Additions)

-(NSInteger)numberOfDaysUntilDay:(NSDate *)aDate; 
-(NSInteger)numberOfHoursUntilDay:(NSDate *)aDate;

@end

@implementation NSDate (Additions)
const NSInteger secondPerMunite = 60;       
const NSInteger munitePerHour = 60;
const NSInteger hourPerDay = 24;

-(NSInteger)numberOfDaysUntilDay:(NSDate *)aDate 
{
    NSInteger selfTimeInterval = [aDate timeIntervalSinceDate:self];   
    return abs(selfTimeInterval / (secondPerMunite * munitePerHour * hourPerDay));    
}

-(NSInteger)numberOfHoursUntilDay:(NSDate *)aDate 
{
    NSInteger selfTimeInterval = [aDate timeIntervalSinceDate:self];
    return abs(selfTimeInterval / (secondPerMunite * munitePerHour));
}
@end

【讨论】：

这是一个非常错误的方法。请改用 NSCalendar 方法。

【解决方案4】：

来自Apple's example，基本上使用NSCalendar：

NSDate * date1 = <however you initialize this>;
NSDate * date2 = <...>;

NSCalendar *gregorian = [[NSCalendar alloc]
                 initWithCalendarIdentifier:NSGregorianCalendar];

NSUInteger unitFlags = NSMonthCalendarUnit | NSDayCalendarUnit;

NSDateComponents *components = [gregorian components:unitFlags
                                          fromDate:date1
                                          toDate:date2 options:0];

NSInteger months = [components month];
NSInteger days = [components day];

【讨论】：

我第一次错过了。这可能就是他没有得到他想要的东西的原因。