UITableView 索引和部分

Question

我有问题。要向表视图添加索引和节，我该怎么做？我正在使用核心数据。我有这样的东西：

- (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

你的NSFetchedResultsController有带有对象的部分，你只需要将表视图的数据源分配给你的类并执行以下操作：

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
    return [[self.fetchedResultsController sections] count];
}
- (NSInteger)tableView:(UITableView *)table numberOfRowsInSection:(NSInteger)section {
    if ([[self.fetchedResultsController sections] count] > 0) {
        id <NSFetchedResultsSectionInfo> sectionInfo = [[self.fetchedResultsController sections] objectAtIndex:section];
        return [sectionInfo numberOfObjects];
    } else
        return 0;
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    UITableViewCell *cell = <#Get the cell#>;
    NSManagedObject *managedObject = [<#Fetched results controller#> objectAtIndexPath:indexPath];
    // Configure the cell with data from the managed object.
    return cell;
}

- (NSString *)tableView:(UITableView *)tableView titleForHeaderInSection:(NSInteger)section { 
    if ([[self.fetchedResultsController sections] count] > 0) {
        id <NSFetchedResultsSectionInfo> sectionInfo = [[<#Fetched results controller#> sections] objectAtIndex:section];
        return [sectionInfo name];
    } else
        return nil;
}

- (NSArray *)sectionIndexTitlesForTableView:(UITableView *)tableView {
    return [<#Fetched results controller#> sectionIndexTitles];
}

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

这取自：

NSFetchedResulstController 类参考