返回与现在日期最近的数组内的对象

Question

我有一个包含对象的数组，每个对象都有一个名为“日期”的属性，我想通过该数组找到与当前日期最接近的对象。

#import <Foundation/Foundation.h>

@interface FixturesObject : NSObject
@property (nonatomic, strong) NSString *homeGoals;
@property (nonatomic, strong) NSString *awayGoals;
@property (nonatomic, strong) NSString *homeName;
@property (nonatomic, strong) NSString *awayName;
@property (nonatomic, strong) NSString *round;
@property (strong, nonatomic) UIImage *homeLogo;
@property (strong, nonatomic) UIImage *awayLogo;
@property (nonatomic, strong) NSString *date;
@property (nonatomic, strong) NSDate *date2;
@property (nonatomic, strong) NSNumber *epoch;


+(FixturesObject *)fixtureFromXMLDictionary: (NSDictionary *)dict;

@end

#import "FixturesObject.h"

@implementation FixturesObject
@synthesize homeGoals, awayGoals, homeLogo, awayLogo, homeName, awayName, round, date, epoch, date2;


+(FixturesObject *)fixtureFromXMLDictionary:(NSDictionary *)dict{

    FixturesObject *object =[[FixturesObject alloc]init];

    object.homeGoals = dict[@"HomeGoals"];
    object.awayGoals = dict[@"AwayGoals"];
    object.homeName = dict[@"HomeTeam"];
    object.awayName = dict[@"AwayTeam"];
    object.homeLogo = [UIImage imageNamed:dict[@"HomeTeam_Id"]];;
    object.awayLogo = [UIImage imageNamed:dict[@"AwayTeam_Id"]];
    object.round = dict[@"Round"];
    object.date = dict[@"Date"];

    NSString * dateString = [NSString stringWithFormat: @"%@",object.date];
    NSDateFormatter* dateFormatter = [[NSDateFormatter alloc] init];
    [dateFormatter setDateFormat:@"yyyy-MM-dd'T'HH:mm:ssZ"];
    NSDate* myDate = [dateFormatter dateFromString:dateString];

    object.date2 = myDate;
    return object;

}

@end

mainview.m

FixturesObject *closestObject;
NSTimeInterval closestInterval = DBL_MAX;

for (FixturesObject *myObject in newFixtureObjectArray) {
    NSTimeInterval interval = ABS([myObject.date2 timeIntervalSinceDate:[NSDate date]]);
    if (interval < closestInterval) {
        closestInterval = interval;
        closestObject = myObject;
                NSLog(@"My closest date: %@", myObject);
    }
}

已按要求更新，非常感谢大家的帮助！

Answer 1

您需要确保 myObject.date 是 NSDate 类的对象。如果它是其他类型的对象，它将不起作用。如果 myObject.date 为 nil，它也不会正常工作。

您报告的新错误 ([NSNull date2]: unrecognized selector sent to instance 0x102f20b50) 对于您报告它的行没有意义。一定有别的事情发生了。

你能用你的新代码更新你原来的问题，并显示你的myObject类的标题吗？

Answer 2

我认为您最好使用sortedArrayUsingComparator 对数组进行排序。

    NSDate *currentDate = [NSDate date];

    NSArray *sortedFixtureObjectArray = [newFixtureObjectArray sortedArrayUsingComparator:^NSComparisonResult(id obj1, id obj2) {

        if (![obj1 isKindOfClass:[FixturesObject class]])
             return NSOrderedDescending;
        else if (![obj2 isKindOfClass:[FixturesObject class]])
            return NSOrderedAscending;

        FixturesObject *one = (FixturesObject *)obj1;
        FixturesObject *two = (FixturesObject *)obj2;

        double firstInterval = [one.date2 timeIntervalSinceDate:currentDate];
        double secondInterval = [two.date2 timeIntervalSinceDate:currentDate];

        firstInterval = (firstInterval < 0 ? -1 * firstInterval : firstInterval);
        secondInterval = (secondInterval < 0 ? -1 * secondInterval: secondInterval);

        if (firstInterval < secondInterval)
            return NSOrderedAscending;
        else if (firstInterval > secondInterval)
            return NSOrderedDescending;

        return NSOrderedSame;

    }];

这将生成一个排序数组，其中第 0 项是与当前日期最接近的时间间隔。

你会注意到我在块外声明了currentDate。这样您就可以将所有日期与同一日期进行比较，而不是每次都使用新日期。