Question

我目前正在尝试找出访问不同UIViewControllers中实体的最佳方式。我目前正在使用以下似乎具有最少的活字节：

View Controller 1在想要显示下一个视图时调用它：

fdvc = [[FormDescriptionViewController alloc] initWithNibName:@"FormDescriptionViewController" bundle:nil andDescriptionEntity:mapEntity.desc];

使用以下命令设置

和View Controller 2（FormDescriptionViewController）：

.h

@property (nonatomic, retain) DescriptionEntity *descriptionEntity;
- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil andDescriptionEntity: (DescriptionEntity *)descE;

.m

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil andDescriptionEntity: (DescriptionEntity *)descE
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
        // Custom initialization
        self.descriptionEntity = descE;
    }
    return self;
}

使用此方法时，我在viewDidLoad中执行以下操作：

- (void)viewDidLoad
{
    [super viewDidLoad];
    // Do any additional setup after loading the view from its nib.

    [self setTitle:@"Form Description"];

    [self.textViewTitle setText:[NSString stringWithString:self.descriptionEntity.map.sName]];

    [self.textViewTitle addObserver:self forKeyPath:@"contentSize" options:(NSKeyValueObservingOptionNew) context:NULL];

    [self.textViewDescription setText:[NSString stringWithString:self.descriptionEntity.sDescription]];

    if (self.descriptionEntity.map.dImage != nil)
    {
        [self.imageView setImage:[UIImage imageWithData:[NSData dataWithData:self.descriptionEntity.map.dImage]]];
    }
    else
        [self.imageView setImage:[UIImage imageNamed:@"wildform.gif"]];

    if ([self.descriptionEntity.map.bDownloaded boolValue] == YES)
        [self.buttonUseForm setTitle:@"Use Map"];
}

这些调用是我与DescriptionEntity相关的唯一调用，但是当我弹出视图控制器时，内存永远不会被释放。我已经执行了堆分析，它告诉我DescriptionEntity是罪魁祸首。要在dealloc方法中进行确认，我尝试在self.descriptionEntity = nil之后调用[descriptionEntity dealloc]。这会在控制器弹出时释放内存，但是当我再次尝试推送受控时，我得到一个糟糕的访问权限，因此我认为现在必须是对DescriptionEntity的唯一引用。

我也尝试过使用NSFetchedResultsController，但这会占用当前方法的两倍以上的活字节数，而且在弹出视图时也无法再次释放内存。

任何人都可以在下一个视图中解释访问此数据的最佳方法，并且有人知道为什么在调用dealloc时我的内存不会被释放吗？

如果您需要任何进一步的信息，请随时提出。

编辑1（声明descriptionEntity）：

我目前正在使用NSFetchedResultsController来抓取我的MapEntities的一个子部分并在UITableView中显示它们。当选择其中一行时，我执行以下操作将DescriptionEntity传递给DescriptionViewController：

- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath
{
    self.viewHasToolbar = YES;

    MapEntity *mapEntity = [_fetchedResultsController objectAtIndexPath:indexPath];

    FormDescriptionViewController *fdvc;

    if ([[UIDevice currentDevice] userInterfaceIdiom] == UIUserInterfaceIdiomPhone) {
        fdvc = [[FormDescriptionViewController alloc] initWithNibName:@"FormDescriptionViewController" bundle:nil andDescriptionEntity:mapEntity.desc];
    } else {
        fdvc = [[FormDescriptionViewController alloc] initWithNibName:@"FormDescriptionViewController_iPad" bundle:nil andDescriptionEntity:mapEntity.desc];
    }

    [self.navigationController pushViewController:fdvc animated:YES];
    [fdvc release];

    [tableView deselectRowAtIndexPath:indexPath animated:NO];
}

_fetchedResultsController的设置如下：

@property (nonatomic, retain) NSFetchedResultsController *fetchedResultsController;

的.m

- (NSFetchedResultsController *)fetchedResultsController {

    if (_fetchedResultsController != nil)
        return _fetchedResultsController;

    Singleton *singleton = [Singleton sharedSingleton];

    NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];
    NSEntityDescription *entity = [NSEntityDescription entityForName:@"MapEntity" inManagedObjectContext:[singleton managedObjectContext]];
    [fetchRequest setEntity:entity];

    NSSortDescriptor *sort = [[NSSortDescriptor alloc] initWithKey:@"sName" ascending:NO];
    [fetchRequest setSortDescriptors:[NSArray arrayWithObject:sort]];

    [fetchRequest setFetchBatchSize:8];

    // Finally check the results
    NSError *error;
    NSArray *fetchedObjects = [[singleton managedObjectContext] executeFetchRequest:fetchRequest error:&error];
    for (MapEntity *map in fetchedObjects)
    {
        NSLog(@"Maps present in database: %@", map.sName);
    }


    NSFetchedResultsController *theFetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest managedObjectContext:[singleton managedObjectContext] sectionNameKeyPath:nil cacheName:@"Root11"];
    self.fetchedResultsController = theFetchedResultsController;
    self.fetchedResultsController.delegate = self;
    [self.fetchedResultsController performFetch:NULL];
    [fetchRequest release];

    return _fetchedResultsController;
}

如何访问不同ViewControllers中的核心数据实体？指针似乎在dealloc上保留

0 个答案: