Question

我需要你的帮助，这个问题让我疯了！我试图让我的UITableView行按字母顺序排序，但我得到的是，每一行都有它自己的部分，两者都是相同的。

我该如何解决这个问题？

这是我的代码：

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
    return [[self.fetchedResultsController sections] count];
}

- (NSArray *)sectionIndexTitlesForTableView:(UITableView *)tableView {
    return [self.fetchedResultsController sectionIndexTitles];
}

- (NSInteger)tableView:(UITableView *)tableView sectionForSectionIndexTitle:(NSString *)title atIndex:(NSInteger)index {
    return [self.fetchedResultsController sectionForSectionIndexTitle:title atIndex:index];
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    id<NSFetchedResultsSectionInfo> sectionInfo = [[self.fetchedResultsController sections] objectAtIndex:section];
    return [sectionInfo numberOfObjects];
}

- (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section {

    id <NSFetchedResultsSectionInfo> sectionInfo = [[self.fetchedResultsController sections] objectAtIndex:section];
    return [sectionInfo name];
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *CellIdentifier = @"ListCell";
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];

    NSManagedObject *aPerson = [self.fetchedResultsController objectAtIndexPath:indexPath];

    cell.textLabel.text = [aPerson valueForKey:@"name"];
    cell.detailTextLabel.text = [aPerson valueForKey:@"number"];

    return cell;
}

// Override to support editing the table view.
- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath
{
    NSManagedObjectContext *managedObjectContext=[self.fetchedResultsController managedObjectContext];
    if (editingStyle == UITableViewCellEditingStyleDelete) {
        // Delete the row from the data source
        [managedObjectContext deleteObject:[self.fetchedResultsController objectAtIndexPath:indexPath]];

        NSError *error;
        if (![managedObjectContext save:&error]) {
            UIAlertView *alert=[[UIAlertView alloc] initWithTitle:NSLocalizedString(@"Error saving after delete", @"Error saving after delete.")
                                                      message:[NSString stringWithFormat:NSLocalizedString(@"Error was: %@, quitting.", @"Error was: %@,quitting."), [error localizedDescription]]
                                                     delegate:self
                                            cancelButtonTitle:NSLocalizedString(@"Aw, Nuts", @"Aw, Nuts")
                                            otherButtonTitles:nil];
            [alert show];
        }
    }
    else if (editingStyle == UITableViewCellEditingStyleInsert) {
        // Create a new instance of the appropriate class, insert it into the array, and add a new row to the table view
    }
}

#pragma mark - Table view delegate

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
    NSManagedObject *selectedHero = [self.fetchedResultsController objectAtIndexPath:indexPath];
    [self performSegueWithIdentifier:@"DetailSegue" sender:selectedHero];
}

#pragma mark - FetchedResultsController Property

- (NSFetchedResultsController *)fetchedResultsController
{
    if (_fetchedResultsController != nil) {
        return _fetchedResultsController;
    }

    NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
    AppDelegate *appDelegate = (AppDelegate *)[[UIApplication sharedApplication] delegate];
    NSManagedObjectContext *managedObjectContext = [appDelegate managedObjectContext];
    NSEntityDescription *entity = [NSEntityDescription entityForName:@"Team"
                                          inManagedObjectContext:managedObjectContext];
    [fetchRequest setEntity:entity];
    [fetchRequest setFetchBatchSize:20];

    NSString *sectionKey = nil;

    NSSortDescriptor *sortDescriptor1 = [[NSSortDescriptor alloc] initWithKey:@"name" ascending:YES];
    NSSortDescriptor *sortDescriptor2 = [[NSSortDescriptor alloc] initWithKey:@"number" ascending:YES];
    NSArray *sortDescriptors = [[NSArray alloc] initWithObjects:sortDescriptor1, sortDescriptor2, nil];
    [fetchRequest setSortDescriptors:sortDescriptors];
    sectionKey = @"name";

    _fetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest managedObjectContext:managedObjectContext sectionNameKeyPath:sectionKey cacheName:@"Team"];
    _fetchedResultsController.delegate = self;

    return _fetchedResultsController;
}

Answer 1

您确定这段代码吗？

- (NSInteger)tableView:(UITableView *)tableView sectionForSectionIndexTitle:(NSString *)title atIndex:(NSInteger)index {
    return [self.fetchedResultsController sectionForSectionIndexTitle:title atIndex:index];
}

这会生成递归循环。

Answer 2

您已将获取的结果控制器的sectionNameKeyPath参数设置为 @"name"，因此FRC为每个名称创建一个表视图部分。

如果您不想要部分，只需设置sectionNameKeyPath:nil即可。

如果您希望根据首字母将名称分组为多个部分，将sectionNameKeyPath设置为刚才包含的实体的（瞬态）属性每个对象的首字母，如例如这里： How to use the first character as a section name

UITableView部分/每个“名称”都是它自己的部分

2 个答案: