ios - 如何在重新进入查看时转储核心数据搜索结果 FRC？

Question

我的核心数据搜索出现问题。加载后，我的整个表格都是可见的。好的。我按下搜索按钮，输入一个术语，然后按下搜索。显示正确的行。好的。

问题是当我从 TableView 返回到顶级 View (多级 TableView )并向下钻取到表时。我之前过滤的搜索结果仍然显示。如何让 FRC 转储之前的搜索谓词并显示条目上的所有记录？

这是我的代码的相关部分:

    - (void)viewDidLoad {
            [super viewDidLoad];

           if (managedObjectContext == nil) { managedObjectContext = [(RecipesAppDelegate *)[[UIApplication sharedApplication] delegate] managedObjectContext]; }

           //search
           UISearchDisplayController *searchDisplayController = [[UISearchDisplayController alloc] initWithSearchBar:sBar contentsController:self];  

           [self performSelector:@selector(setSearchDisplayController:) withObject:searchDisplayController];

           [searchDisplayController setDelegate:self];  
           [searchDisplayController setSearchResultsDataSource:self];  
           [searchDisplayController setSearchResultsDelegate:self];
           [searchDisplayController release];  

           NSError *error;
           if (![[self fetchedResultsController] performFetch:&error]) {
            NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
            exit(-1);
           }

           self.filteredListContent = [NSMutableArray arrayWithCapacity:[[[self fetchedResultsController] fetchedObjects] count]];  
}

- (void)searchBarSearchButtonClicked:(UISearchBar *)searchBar {

    if (self.sBar.text !=nil)
    {
        NSPredicate *predicate =[NSPredicate predicateWithFormat:@"name contains[cd] %@", self.sBar.text];

        [fetchedResultsController.fetchRequest setPredicate:predicate];
    }

    NSError *error = nil;
    if (![[self fetchedResultsController] performFetch:&error]) {
        // Handle error
        NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
        exit(-1);  // Fail
    }           

    [self.myTable reloadData];

    [sBar resignFirstResponder];  

}

- (NSFetchedResultsController *)fetchedResultsController {

    // Set up the fetched results controller if needed.
    if (fetchedResultsController == nil) {

        // Create the fetch request for the entity.
        NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];

        // Edit the entity name as appropriate.
        NSEntityDescription *entity = [NSEntityDescription entityForName:@"MyEntity" inManagedObjectContext:managedObjectContext];
        [fetchRequest setEntity:entity];

        //set batch size
        [fetchRequest setFetchBatchSize:20];

        // Edit the sort key as appropriate.
        NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"name" ascending:YES];
        NSArray *sortDescriptors = [[NSArray alloc] initWithObjects:sortDescriptor, nil];

        [fetchRequest setSortDescriptors:sortDescriptors];

        // Edit the section name key path and cache name if appropriate.
        // nil for section name key path means "no sections".
        NSFetchedResultsController *aFetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest managedObjectContext:managedObjectContext sectionNameKeyPath:@"name" cacheName:nil];
        aFetchedResultsController.delegate = self;
        self.fetchedResultsController = aFetchedResultsController;

        [aFetchedResultsController release];
        [fetchRequest release];
        [sortDescriptor release];
        [sortDescriptors release];
    }

    return fetchedResultsController;
}

- (void)viewDidUnload {
    self.filteredListContent = nil;
    self.fetchedResultsController = nil;
}


- (void)dealloc {
    self.filteredListContent = nil;
    self.fetchedResultsController = nil;

    [fetchedResultsController release];
    [managedObjectContext release];

    [filteredListContent release];

    [myTable release];

    [super dealloc];
}

谢谢

更新:明白了，谢谢。我只是调用这个方法:

- (void)loadClean {

    if(fetchedResultsController){
        [fetchedResultsController release];
    }

    fetchedResultsController = nil;

    NSError *error;
    if (![[self fetchedResultsController] performFetch:&error]) {
        NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
        exit(-1);
    }

    [self.myTable reloadData];
}

Answer 1

您需要为 FRC 提供新的获取请求并删除其缓存。如果您使用相同的获取请求，您将获得相同的返回。