Question

我声明了2个NSMutableArrays。一个填充了名称，然后另一个填充了NSDate的字符串值。

我想根据第二个日期中的日期对它们进行排序。例如，如果日期数组中的元素3变为元素0，我希望名称数组发生相同的事情。

最简单的方法是什么？我知道如何排序日期数组只是不对应的名称数组！（Objective-C Please！）

Answer 1

对2个数组进行排序并使它们保持同步是一件痛苦的事。你基本上必须手工排序。

最简单的方法可能是创建一个字典数组，其中每个字典都包含数据和名称。

然后按日期对字典数组进行排序。

编辑：

以下是创建包含名称和日期的自定义对象的代码。有按日期排序的代码以及按名称排序的代码：

/**
 The thing class has a property date and a property name. 
 It is purely for creating sorted arrays of objects
 */
@interface Thing : NSObject

@property (nonatomic, strong) NSDate *date;
@property (nonatomic, strong) NSString *name;

@end

@implementation Thing

/**
 This is a dummy init method that creates a Thing ojbect with a random name and date
 */
- (instancetype) init {
  self = [super init];
  if (!self) return nil;

  NSString *letters = @"ABCDEFGHIJKLMNOPQRSTUVWXYZ";
  NSMutableString *temp = [NSMutableString new];
  for (int x = 0; x < 10; x++) {
    unichar aChar = [letters characterAtIndex:arc4random_uniform(26)];
    [temp appendFormat: @"%C", aChar];
  }
  self.name = [temp copy];

  //Create a random date
  uint32 halfMax = 2000000000;
  uint32 max = halfMax * 2;
  int32_t value = arc4random_uniform(max) - halfMax;
  NSTimeInterval now = [[NSDate date] timeIntervalSinceReferenceDate];
  self.date = [NSDate dateWithTimeIntervalSinceReferenceDate: now + value];
  return self;
}

- (NSString *) description {
  return [NSString stringWithFormat: @"Name: %@  Date: %@", self.name, self.date];
}

@end




int main(int argc, const char * argv[]) {
  @autoreleasepool {
    //Create an array of Thing objects
    const int count = 50;
    NSMutableArray *thingArray = [NSMutableArray arrayWithCapacity: count];
    for (int x = 0; x < count; x++) {
      thingArray[x] = [[Thing alloc] init];
    }
    #if 1
      //Sort by date, ascending
      [thingArray sortUsingComparator:^NSComparisonResult(Thing  *obj1,
                                                          Thing  *obj2) {
        NSComparisonResult bigger =  
          [obj1.date timeIntervalSinceReferenceDate] < 
          [obj2.date timeIntervalSinceReferenceDate] ?  
            NSOrderedAscending : NSOrderedDescending;
        return bigger;
      }];
    #else
      //Sort by name
      [thingArray sortUsingComparator:^NSComparisonResult(Thing  *obj1,
                                                          Thing  *obj2) {
        return [obj1.name compare: obj2.name];
      }];
    #endif
    NSLog(@"%@", thingArray);
  }
    return 0;
}

按日期排序2个NSArrays

1 个答案:

编辑：