iphone - 如何按距离升序对 NSmutablearray 进行排序？

Question

我有一个 nsmutable 数组的 friend 列表。每个人都有他们的纬度和经度。我想用他们与 autor 的距离的升序对该数组进行排序。我发现了与 autor 的 friend 的距离值，现在我想要按照距离的升序对该数组进行排序。我就是这样做的，`

for(int i=0;i<[searchfriendarray count];i++)
        {
            NSDictionary *payload =[searchfriendarray objectAtIndex:i];
            NSLog(@"%@",payload);
             NSString *memberid = [payload objectForKey:@"userID"];
             CLLocation *locationofauthor;
            CLLocation *locationoffriends;
           if([memberid isEqualToString:uidstr])
            {

               NSString *latofauthor = [payload objectForKey:@"latitude"]; 
               NSString *longofauthor=[payload objectForKey:@"longitude"];
              double latofauthordouble = [latofauthor doubleValue];
             double longofauthordouble=[longofauthor doubleValue];;
            locationofauthor = [[CLLocation alloc] initWithLatitude:latofauthordouble  longitude:longofauthordouble];

            }
            else
            {
             NSString *latoffriends = [payload objectForKey:@"latitude"]; 
             NSString *longoffriends=[payload objectForKey:@"longitude"];
               double latoffriendsdouble = [latoffriends doubleValue];
                double longoffriendsdouble=[longoffriends doubleValue];;
               locationoffriends = [[CLLocation alloc] initWithLatitude:latoffriendsdouble  longitude:longoffriendsdouble];

              }
             CLLocationDistance distance = [locationofauthor distanceFromLocation:locationoffriends];

}

`任何人都可以帮助我按照距离的升序对我的数组进行排序吗？

Answer 1

您可以提供两个对象之间的比较代码块。然后 NSArray 将根据需要多次调用您的 block 来对数组进行排序。

NSArray sortedArray = [yourUnsortedArray sortedArrayUsingComparator:^NSComparisonResult(id         obj1, id obj2) {
       /*some code to compare obj1 to obj2. 
       for instance, compare the distances of obj1 to obj2.
       Then return an  NSComparisonResult 
       (NSOrderedAscending, NSOrderedSame, NSOrderedDescending);*/
    }];

附注要再次获取可变数组，只需对返回的对象调用 mutableCopy。