Question

嘿伙计们，我有一个UISegmented控制器，我正试图在核心数据的提取结果之间切换。但是，当分段控制器更改时，它不会更新UITableView中的获取结果。我不确定我做错了什么。希望有人可以指出我正确的方向。这是我的代码：

- (void)viewDidLoad {
NameAppDelegate *theDelegate = (NameAppDelegate*)[[UIApplication sharedApplication] delegate];
    self.managedObjectContext = theDelegate.managedObjectContext;
    NSError *error = nil;
    if (![[self fetchedResultsController] performFetch:&error]) {
        NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
        abort();
    }
    [super viewDidLoad];
}

- (IBAction)segmentedControlValueChanged {
    selectedUnit = tableSeg.selectedSegmentIndex;
    [self.theTableView reloadData];
}

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {

    if (selectedUnit == 0) {
    return [[fetchedResultsController sections] count];
    }

            if (selectedUnit == 1) {
                return [[fetchedResultsController2 sections] count];
            }
    return 0;
}


- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
    if (selectedUnit == 0) {
    id <NSFetchedResultsSectionInfo> sectionInfo = [[fetchedResultsController sections] objectAtIndex:section];
    return [sectionInfo numberOfObjects];
    }
    if (selectedUnit == 1) {
        id <NSFetchedResultsSectionInfo> sectionInfo = [[fetchedResultsController2 sections] objectAtIndex:section];
        return [sectionInfo numberOfObjects];
    }
    return 0;
}


- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {
    if (selectedUnit == 0) {
    NSManagedObject *managedObject = [fetchedResultsController objectAtIndexPath:indexPath];
    static NSString *cellID = @"nameCell";

    NamesViewCustomCell *cell = (NamesViewCustomCell*)[tableView dequeueReusableCellWithIdentifier:cellID];
    if (cell == nil) {
        NSLog(@"New Cell Made");

        NSArray *topLevelObjects = [[NSBundle mainBundle] loadNibNamed:@"NamesViewCustomCell" owner:nil options:nil];
        for(id currentObject in topLevelObjects)
        {
            if([currentObject isKindOfClass:[NamesViewCustomCell class]])
            {
                cell = (NamesViewCustomCell *)currentObject;
                break;
            }
        }
    }
    NSDateFormatter* formatter = [[NSDateFormatter alloc] init];
    [formatter setDateStyle:NSDateFormatterLongStyle];
    [formatter setTimeStyle:NSDateFormatterShortStyle];

    // Configure the cell.
    [[cell nameName2] setText:[managedObject valueForKey:@"nameContent"]];

    return cell;
    }
    if (selectedUnit == 1) {
        NSManagedObject *managedObject = [fetchedResultsController2 objectAtIndexPath:indexPath];
        static NSString *CellIdentifier = @"Cell";

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

        // Configure the cell.
        cell.textLabel.text = [managedObject valueForKey:@"nameContent"];

        return cell;
    }
    return 0;
}


- (void)tableView:(UITableView *)tableView didSelectRowAtIndexPath:(NSIndexPath *)indexPath {

    if (selectedUnit == 0) {
    RecipeDetailViewController *recipeDetailView = [[RecipeDetailViewController alloc] initWithStyle:UITableViewStyleGrouped];
    AddName *addName = (AddName *)[fetchedResultsController objectAtIndexPath:indexPath];
    recipeDetailView.addName = addName;
    [self.navigationController pushViewController:recipeDetailView animated:YES];
    }
    if (selectedUnit == 1) {
        RecipeDetailViewController *recipeDetailView = [[RecipeDetailViewController alloc] initWithStyle:UITableViewStyleGrouped];
        AddName2 *addName2 = (AddName2 *)[fetchedResultsController2 objectAtIndexPath:indexPath];
        recipeDetailView.addName2 = addName2;
        [self.navigationController pushViewController:recipeDetailView animated:YES];
    }
}
- (NSFetchedResultsController *)fetchedResultsController {

    if (selectedUnit == 0) {

        if (fetchedResultsController) return fetchedResultsController;

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

        [fetchRequest setEntity:entity];

        NSSortDescriptor *sortDescriptor = 
        [[NSSortDescriptor alloc] initWithKey:@"timeStamp" 
                                    ascending:YES];

        NSArray *sortDescriptors = [[NSArray alloc] 
                                    initWithObjects:sortDescriptor, nil];  
        [fetchRequest setSortDescriptors:sortDescriptors];

        NSFetchedResultsController *aFetchedResultsController = 
        [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest 
                                            managedObjectContext:managedObjectContext
                                              sectionNameKeyPath:nil cacheName:@"cache"];
        aFetchedResultsController.delegate = self;
        [self setFetchedResultsController:aFetchedResultsController];

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

        return fetchedResultsController;

    }
    if (selectedUnit == 1) {

        if (fetchedResultsController2 != nil) {
            return fetchedResultsController2;
        }


        NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] init];

        NSEntityDescription *entity = [NSEntityDescription entityForName:@"AddName2" inManagedObjectContext:managedObjectContext];
        [fetchRequest setEntity:entity];

        [fetchRequest setFetchBatchSize:20];

        NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"timeStamp" ascending:NO];
        NSArray *sortDescriptors = [[NSArray alloc] initWithObjects:sortDescriptor, nil];

        [fetchRequest setSortDescriptors:sortDescriptors];

        NSFetchedResultsController *aFetchedResultsController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest managedObjectContext:managedObjectContext sectionNameKeyPath:nil cacheName:@"cache2"];
        aFetchedResultsController.delegate = self;
        self.fetchedResultsController2 = aFetchedResultsController;

        [aFetchedResultsController release];
        [fetchRequest release];
        [sortDescriptor release];
        [sortDescriptors release];
        return fetchedResultsController2;

    }

return 0;

}

Answer 1

您需要将其放在- (IBAction)segmentedControlValueChanged

中

if (![[self fetchedResultsController] performFetch:&error]) {
    NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
    abort();
}

UITableView不会刷新核心数据的提取结果

1 个答案: