tableView reloadData 不起作用

Question

我在标签栏应用程序中有一个表格视图。

我正在加载viewDidLoad中的数据

managedObjectContext = nil;
managedObjectContext = [(RecipesAppDelegate *)[[UIApplication sharedApplication] delegate] managedObjectContext];
NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
NSEntityDescription *entity = [NSEntityDescription entityForName:@"BrilliantMustache" inManagedObjectContext:managedObjectContext];
[fetchRequest setEntity:entity];
NSPredicate *predicate = [NSPredicate predicateWithFormat:@"badge.length > 0"];
[fetchRequest setPredicate:predicate];
NSSortDescriptor *sortDescriptor1 = [[NSSortDescriptor alloc] initWithKey:@"badge" ascending:YES];
NSSortDescriptor *sortDescriptor2 = [[NSSortDescriptor alloc] initWithKey:@"name" ascending:YES];
NSArray *sortDescriptors = [[NSArray alloc] initWithObjects:sortDescriptor1,sortDescriptor2, nil];
[fetchRequest setSortDescriptors:sortDescriptors];
NSFetchedResultsController *aFetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest managedObjectContext:managedObjectContext sectionNameKeyPath:@"badge" cacheName:nil];
aFetchedResultsController.delegate = self;
self.fetchedResultsController = aFetchedResultsController;
[aFetchedResultsController release];
[fetchRequest release];
[sortDescriptor1 release];
[sortDescriptor2 release];
[sortDescriptors release];

我正在尝试重新加载viewWillAppear中的数据

- (void)viewWillAppear:(BOOL)animated {
    [self.tableView reloadData];
}

在这个视图中，我调用了另一个视图，它在更改时会在发布时更新核心数据。当我导航回 tableview 时，它不会更新。它会更新的唯一方法是，如果我退出应用程序并从头开始重新加载。

总共有 2 个单独的表格视图。奇怪的是，第一个 tableview 确实刷新了。

有什么想法吗？ 抢

Answer 1

你需要在viewDidLoad 中做你在viewWillAppear 中所做的事情。 viewDidLoad 仅在启动时调用，因此尽管更改了数据，但您的视图永远不会更改自己的本地数据，因此当您调用 reloadData 时，它仍然使用旧数据。

编辑：

你应该拥有的：

- (void)viewWillAppear:(BOOL)animated {
    managedObjectContext = nil;
    managedObjectContext = [(RecipesAppDelegate *)[[UIApplication sharedApplication] delegate] managedObjectContext];
    NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
    NSEntityDescription *entity = [NSEntityDescription entityForName:@"BrilliantMustache" inManagedObjectContext:managedObjectContext];
    [fetchRequest setEntity:entity];
    NSPredicate *predicate = [NSPredicate predicateWithFormat:@"badge.length > 0"];
    [fetchRequest setPredicate:predicate];
    NSSortDescriptor *sortDescriptor1 = [[NSSortDescriptor alloc] initWithKey:@"badge" ascending:YES];
    NSSortDescriptor *sortDescriptor2 = [[NSSortDescriptor alloc] initWithKey:@"name" ascending:YES];
    NSArray *sortDescriptors = [[NSArray alloc] initWithObjects:sortDescriptor1,sortDescriptor2, nil];
    [fetchRequest setSortDescriptors:sortDescriptors];
    NSFetchedResultsController *aFetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest managedObjectContext:managedObjectContext sectionNameKeyPath:@"badge" cacheName:nil];
    aFetchedResultsController.delegate = self;
    self.fetchedResultsController = aFetchedResultsController;
    [aFetchedResultsController release];
    [fetchRequest release];
    [sortDescriptor1 release];
    [sortDescriptor2 release];
    [sortDescriptors release];

    [self.tableView reloadData];
    [super viewWillAppear:animated];
}

- (void)viewDidLoad:(BOOL)animated {
    [super viewDidLoad:animated];
}

Answer 2

您是否正确实施了NSFetchedResultsControllerDelegate 方法？当 FRC 收到来自托管对象上下文的更改通知时，它应该处理更新表...

编辑： NSFetchedResultsController Class Reference