排序类别（列），因为它们存储在 Parse 后端

Question

我正在尝试使用列 "Category" 数据填充来自 Parse 的餐馆数据作为项目列表的部分标题。但是，项目的部分标题会随机显示。我希望它们在存储在后端时显示出来。我试着做 [query orderByAscending:@"Category"];它按字母顺序对类别进行排序并且结果没有变化。下面是我当前的实现...

-(void) listAllItems {

    PFQuery *query  = [PFQuery queryWithClassName:[NSString stringWithString:self.restaurantName]];


    [query whereKey:@"DinnerLunch" containsString:self.lunchDinnerPreference];

    [query findObjectsInBackgroundWithBlock:^(NSArray *objects, NSError *error) {
        if (!error) {

            for (PFObject *obj in objects) {

                self.curatedItemDictionary = [[NSMutableDictionary alloc]init];

                [_curatedItemDictionary setValue:[obj objectForKey:@"ItemName"] forKey:@"ItemName"];
                [_curatedItemDictionary setValue:[obj objectForKey:@"Price"] forKey:@"Price"];
                [_curatedItemDictionary setValue:[obj objectForKey:@"Category"] forKey:@"Category"];

                [_curatedItemDictionary setValue:@"" forKey:@"ModifiableItems"];
                _sectionsArray = [_sectionsDictionary objectForKey: [obj objectForKey:@"Category"]];

                if(nil == _sectionsArray){
                    self.sectionsArray = [[NSMutableArray alloc]init];
                }

                [_sectionsArray addObject:_curatedItemDictionary];
                [_sectionsDictionary setObject: _sectionsArray forKey: [obj objectForKey:@"Category"]];

                NSLog(@"categories keys are %@", [self.sectionsDictionary allKeys]);
            }            

            [self.tableView reloadData];
            } else {
                // Log details of the failure
                NSLog(@"Error: %@ %@", error, [error userInfo]);
            }
        }];
    }

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView{
    return [_sectionsDictionary count];
}

- (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section{
    NSArray *keys = [self.sectionsDictionary allKeys];

    return [keys objectAtIndex:section];
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    NSArray *keys = [self.sectionsDictionary allKeys];
    id aKey = [keys objectAtIndex:section];
    NSMutableArray *arr = [self.sectionsDictionary objectForKey:aKey];
    return (arr) ? arr.count : 0;
}

Answer 1

我通过创建一个新的 NSMutableArray 修复了它。实际上我是从这个 post How can i get Original order of NSDictionary/NSMutableDictionary?

读到的

我在遍历 PFObjects [_categoryMutableArray addObject:[obj objectForKey:@"Category"]]; 时添加了这一行，然后我在 titleForHeaderInSection 和 numberOfRowsInSection

中使用了以下几行

- (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section{        
    return [_categoryMutableArray objectAtIndex:section];
}


- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
//    NSArray *keys = [self.sectionsDictionary allKeys];
    id aKey = [_categoryMutableArray objectAtIndex:section];
    NSMutableArray *arr = [self.sectionsDictionary objectForKey:aKey];
    return (arr) ? arr.count : 0;
}

排序类别（列），因为它们存储在 Parse 后端

Order the Categories (column) as they are stored in Parse backend

objective-c

nsmutabledictionary

ios

parse-platform

pfquery