Question

我正在尝试显示包含2个部分的表格视图。第一部分将始终具有1行，第二部分将具有与数据点一样多的行。我正在使用Core Data和以下tableView：numberOfRowsInSection：method ...

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    if (section == 0) {
        return 1;
    } else {
        id <NSFetchedResultsSectionInfo> sectionInfo = [[self.fetchedResultsController sections] objectAtIndex:section];
        return [sectionInfo numberOfObjects];
    }
}

但是，我收到以下错误：

由于未捕获的异常'NSRangeException'而终止应用程序，原因： ' * - [__ NSArrayM objectAtIndex：]：索引1超出边界[0 .. 0]'

任何帮助将不胜感激。感谢。

NEW ---------------------------------------------- ---------------------------------

这是相关方法的当前实现：

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    if (section == 0) {
        return 1;
    } else {
        NSUInteger frcSection = section - 1;
        id <NSFetchedResultsSectionInfo> sectionInfo = [[self.fetchedResultsController sections] objectAtIndex:frcSection];
        return [sectionInfo numberOfObjects];
    }
}

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

    if (cell == nil) {
        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
    }

    [self configureCell:cell atIndexPath:indexPath];
    return cell;
}

- (void)configureCell:(UITableViewCell *)cell atIndexPath:(NSIndexPath *)indexPath
{
    if (indexPath.section == 0) {
        cell.textLabel.text = entityOne.name;  //entityOne object passed from previous VC
    } else {
        entityTwo = [self.fetchedResultsController objectAtIndexPath:indexPath];
        cell.textLabel.text = entityTwo.name;
    }
}

- (void)controller:(NSFetchedResultsController *)controller
  didChangeSection:(id <NSFetchedResultsSectionInfo>)sectionInfo
           atIndex:(NSUInteger)sectionIndex
     forChangeType:(NSFetchedResultsChangeType)type
{
    NSUInteger frcSectionIndex = 0;
    frcSectionIndex = sectionIndex + 1;

    switch(type) {
        case NSFetchedResultsChangeInsert:
            [self.tableView insertSections:[NSIndexSet indexSetWithIndex:frcSectionIndex] withRowAnimation:UITableViewRowAnimationFade];
            break;

        case NSFetchedResultsChangeDelete:
            [self.tableView deleteSections:[NSIndexSet indexSetWithIndex:frcSectionIndex] withRowAnimation:UITableViewRowAnimationFade];
            break;
    }
}

- (void)controller:(NSFetchedResultsController *)controller
   didChangeObject:(id)anObject
       atIndexPath:(NSIndexPath *)indexPath
     forChangeType:(NSFetchedResultsChangeType)type
      newIndexPath:(NSIndexPath *)newIndexPath
{
    UITableView *tableView = self.tableView;

    switch(type) {
        case NSFetchedResultsChangeInsert:
            [tableView insertRowsAtIndexPaths:@[newIndexPath] withRowAnimation:UITableViewRowAnimationFade];
            break;

        case NSFetchedResultsChangeDelete:
            [tableView deleteRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationFade];
            break;

        case NSFetchedResultsChangeUpdate:
            [self configureCell:[tableView cellForRowAtIndexPath:indexPath] atIndexPath:indexPath];
            break;

        case NSFetchedResultsChangeMove:
            [tableView deleteRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationFade];
            [tableView insertRowsAtIndexPaths:@[newIndexPath] withRowAnimation:UITableViewRowAnimationFade];
            break;
    }
}

Answer 1

原因是获取的结果控制器（FRC）只有一个部分（部分＃0 ），您希望在第二部分显示（部分＃1 。

这是可能的，但您必须在FRC部分编号和表格视图部分编号之间进行映射，例如

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section { if (section == 0) { return 1; } else { NSUInteger frcSection = section - 1; id <NSFetchedResultsSectionInfo> sectionInfo = [[self.fetchedResultsController sections] objectAtIndex:frcSection]; return [sectionInfo numberOfObjects]; } }

cellForRowAtIndexPath中需要相同的映射。

在FRC委托方法didChangeObject，didChangeSection中，您必须在调用表格视图方法（例如insertRowsAtIndexPaths）之前将1 添加到节号。

已添加： configureCell应如下所示：

- (void)configureCell:(UITableViewCell *)cell atIndexPath:(NSIndexPath *)indexPath { if (indexPath.section == 0) { cell.textLabel.text = entityOne.name; //entityOne object passed from previous VC } else { NSIndexPath *frcIndexPath = [NSIndexPath indexPathForRow:indexPath.row inSection:(indexPath.section - 1)]; entityTwo = [self.fetchedResultsController objectAtIndexPath:frcIndexPath]; cell.textLabel.text = entityTwo.name; } }

和didChangeObject是这样的：

- (void)controller:(NSFetchedResultsController *)controller didChangeObject:(id)anObject atIndexPath:(NSIndexPath *)indexPath forChangeType:(NSFetchedResultsChangeType)type newIndexPath:(NSIndexPath *)newIndexPath { UITableView *tableView = self.tableView; NSIndexPath *tvIndexPath = [NSIndexPath indexPathForRow:indexPath.row inSection:(indexPath.section + 1)]; NSIndexPath *tvNewIndexPath = [NSIndexPath indexPathForRow:newIndexPath.row inSection:(newIndexPath.section + 1)]; switch(type) { case NSFetchedResultsChangeInsert: [tableView insertRowsAtIndexPaths:@[tvNewIndexPath] withRowAnimation:UITableViewRowAnimationFade]; break; case NSFetchedResultsChangeDelete: [tableView deleteRowsAtIndexPaths:@[tvIndexPath] withRowAnimation:UITableViewRowAnimationFade]; break; case NSFetchedResultsChangeUpdate: [self configureCell:[tableView cellForRowAtIndexPath:tvIndexPath] atIndexPath:tvIndexPath]; break; case NSFetchedResultsChangeMove: [tableView deleteRowsAtIndexPaths:@[tvIndexPath] withRowAnimation:UITableViewRowAnimationFade]; [tableView insertRowsAtIndexPaths:@[tvNewIndexPath] withRowAnimation:UITableViewRowAnimationFade]; break; } }

你可能会明白这个想法：

从FRC索引路径转到表视图索引路径时，请在该部分中添加一个。

从表视图索引路径转到FRC索引路径时，从该部分中减去一个。

numberOfRowsInSection：核心数据和多个部分的方法

1 个答案: