Question

我想添加在我的核心数据库中搜索的功能我有一个带有自定义单元格的表格视图但它们只有8并且它们不可编辑现在，我向searchView的headerView添加了一个带有searchDisplayController的searchBar，我想使用NSFetchedResultsController来管理搜索数据。
我试着编写这段代码，但它不起作用......

-(void)createSearch
{
    UISearchBar *searchBar = [[UISearchBar alloc] initWithFrame:CGRectMake(0, 0, 320, 44)];
    searchBar.delegate = self;
    searchBar.scopeButtonTitles = [NSArray arrayWithObjects:@"All", @"Title", @"Notes", @"Tags", nil];
    searchBar.showsScopeBar = YES;
    self.tableView.tableHeaderView = searchBar;
    [searchBar setBackgroundImage:[UIImage imageNamed:@"navbarBg"]];

    searchController = [[UISearchDisplayController alloc] initWithSearchBar:searchBar contentsController:self];
    searchController.delegate = self;
    searchController.searchResultsDataSource = self;
    searchController.searchResultsDelegate = self;
}

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

    NSFetchRequest *request = [[NSFetchRequest alloc] initWithEntityName:@"Task"];
    [request setFetchBatchSize:20];

    NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"title" ascending:YES];
    NSArray *descriptors = [NSArray arrayWithObject:sortDescriptor];
    [request setSortDescriptors:descriptors];

    NSFetchedResultsController *afrc = [[NSFetchedResultsController alloc] initWithFetchRequest:request managedObjectContext:self.managedObjectContext sectionNameKeyPath:nil cacheName:nil];
    afrc.delegate = self;
    searchResultsController = afrc;

    return searchResultsController;
}

-(void)controllerWillChangeContent:(NSFetchedResultsController *)controller
{
    [self.searchController.searchResultsTableView beginUpdates];
}

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

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

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

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

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

-(void)controller:(NSFetchedResultsController *)controller didChangeSection:(id<NSFetchedResultsSectionInfo>)sectionInfo atIndex:(NSUInteger)sectionIndex forChangeType:(NSFetchedResultsChangeType)type
{
    UITableView *tableView = self.searchController.searchResultsTableView;

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

        case NSFetchedResultsChangeDelete:
            [tableView deleteSections:[NSIndexSet indexSetWithIndex:sectionIndex] withRowAnimation:UITableViewRowAnimationFade];
            break;
    }
}

-(void)controllerDidChangeContent:(NSFetchedResultsController *)controller
{
    [self.searchController.searchResultsTableView endUpdates];
}

-(void)searchBar:(UISearchBar *)searchBar textDidChange:(NSString *)searchText
{
    NSPredicate *predicate = nil;

    if (self.searchController.searchBar.selectedScopeButtonIndex == 0)
    {
        predicate = [NSPredicate predicateWithFormat:@"1=1"];
    }
    else if (self.searchController.searchBar.selectedScopeButtonIndex == 1)
    {
        predicate = [NSPredicate predicateWithFormat:@"title CONTAINS[c] %@", searchText];
    }
    else if (self.searchController.searchBar.selectedScopeButtonIndex == 2)
    {
        predicate = [NSPredicate predicateWithFormat:@"notes CONTAINS[c] %@", searchText];
    }
    /*else
    {
        predicate = [NSPredicate predicateWithFormat:@"tags
    }*/

    [self.searchResultsController.fetchRequest setPredicate:predicate];

    [self.searchController.searchResultsTableView reloadData];
}

这些是tableView委托和dataSource方法：

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView
{
    if (tableView == self.searchController.searchResultsTableView)
    {
        return [[self.searchResultsController sections] count];
    }
    else
    {
        return 1;
    }
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section
{
    if (tableView == self.searchController.searchResultsTableView)
    {
        id <NSFetchedResultsSectionInfo> sectionInfo = [[self.searchResultsController sections] objectAtIndex:section];
        return [sectionInfo numberOfObjects];
    }
    else
    {
        return 8;
    }
}

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    if (tableView == self.searchController.searchResultsTableView)
    {
        static NSString *SearchCellIdentifier = @"SearchCell";

        UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:SearchCellIdentifier];
        if (cell == nil)
        {
            cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:SearchCellIdentifier];
        }

        [self configureCell:cell toIndexPath:indexPath];

        return cell;
    }
    else
    {
        static NSString *CellIdentifier = @"Cell";

        MainTableCell *cell = (MainTableCell *)[tableView dequeueReusableCellWithIdentifier:CellIdentifier];
        if (cell == nil) {
            cell = [[MainTableCell alloc] initWithStyle:UITableViewCellStyleDefault reuseIdentifier:CellIdentifier];
            cell.accessoryView = [[UIImageView alloc] initWithImage:[UIImage imageNamed:@"accessoryView"]];
        }

        [self configureCell:cell fromArray:cellImages toIndexPath:indexPath];

        return cell;
    }
}

为什么不起作用？

非常感谢你;）

Answer 1

在您调用reloadData之前，在您的searchBar：textDidChange：消息的末尾

：

[searchResultsController release]; searchResultsController = nil;

用核心数据iPhone实现搜索

1 个答案: