Question

我有一个表视图，我正在执行删除，一切正常，直到我在表视图控制器类中更改我的代码，以使用提供应用程序数据的类管理器，称为LocalDataManager。

我可以滑动并看到红色按钮进行删除，但单击它时没有任何反应。

我在调试器中发现问题出在我的numberOfRowsInSection方法中。

这是我的表格视图：

#import "StackTableViewController.h"
#import "Target.h"
#import "StackTableViewCell.h"
#import "HomeViewController.h"

@interface StackTableViewController () <NSFetchedResultsControllerDelegate>

@end

@implementation StackTableViewController

- (id)init {

    self = [super initWithNibName:@"StackTableViewController" bundle:nil];
    if (self) {
        // Do something
        localDataManager = [[LocalDataManager alloc] init];
    }
    return self;
}


- (void)viewDidLoad {

    [super viewDidLoad];

    self.navigationItem.rightBarButtonItem = self.editButtonItem;

    [localDataManager reloadData];

    //[self.fetchedResultController performFetch:nil];
}


- (void)viewWillLayoutSubviews {

    [self.navigationController setNavigationBarHidden:NO animated:YES];

}

- (void)viewWillDisappear:(BOOL)animated {

    [self.navigationController setNavigationBarHidden:YES animated:YES];
}

// just to ignor a warning
- (CGFloat)tableView:(UITableView *)tableView heightForRowAtIndexPath:(NSIndexPath *)indexPath
{
    return 44;
}


- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

#pragma mark - Table view data source

- (NSInteger)numberOfSectionsInTableView:(UITableView *)tableView {
    // Return the number of sections.
    return localDataManager.fetchedResultController.sections.count;
}

- (NSInteger)tableView:(UITableView *)tableView numberOfRowsInSection:(NSInteger)section {
    // Return the number of rows in the section.
    id <NSFetchedResultsSectionInfo> sectionInfo = [localDataManager.fetchedResultController sections][section];
    return [sectionInfo numberOfObjects];
}




- (UITableViewCellEditingStyle)tableView:(UITableView *)tableView editingStyleForRowAtIndexPath:(NSIndexPath *)indexPath
{
    return UITableViewCellEditingStyleDelete;
}


- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath {

    Target *target = [localDataManager.fetchedResultController objectAtIndexPath:indexPath];

    [[localDataManager.stack managedObjectContext] deleteObject:target];

    [localDataManager.stack saveContext];


    if ([_delegate respondsToSelector:@selector(didDeleteObject)]) {
        [_delegate didDeleteObject];
    }

}


- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath {


    static NSString *cellIdentifier = @"StackTableViewCell";

    Target *target = [localDataManager.fetchedResultController objectAtIndexPath:indexPath];

    StackTableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier];

    if (!cell)
    {
        NSArray *topLevelObjects = [[NSBundle mainBundle] loadNibNamed:@"StackTableViewCell" owner:self options:nil];
        cell = [topLevelObjects objectAtIndex:0];
    }

    cell.cellLabel.text = target.body;

    cell.cellLabel.font = [UIFont fontWithName:@"Candara-Bold" size:20];

    // Configure the cell...

    return cell;
}


- (void)controller:(NSFetchedResultsController *)controller didChangeSection:(id<NSFetchedResultsSectionInfo>)sectionInfo atIndex:(NSUInteger)sectionIndex forChangeType:(NSFetchedResultsChangeType)type {

    switch (type) {
        case NSFetchedResultsChangeInsert:
            [self.tableView insertSections:[NSIndexSet indexSetWithIndex:sectionIndex] withRowAnimation:UITableViewRowAnimationAutomatic];
            break;
        case NSFetchedResultsChangeDelete:
            [self.tableView deleteSections:[NSIndexSet indexSetWithIndex:sectionIndex] withRowAnimation:UITableViewRowAnimationAutomatic];

        default:
            break;
    }
}


- (void)controllerWillChangeContent:(NSFetchedResultsController *)controller {

    [self.tableView beginUpdates];
}


- (void)controller:(NSFetchedResultsController *)controller didChangeObject:(id)anObject atIndexPath:(NSIndexPath *)indexPath forChangeType:(NSFetchedResultsChangeType)type newIndexPath:(NSIndexPath *)newIndexPath {

    switch (type) {
        case NSFetchedResultsChangeInsert:
            [self.tableView insertRowsAtIndexPaths:@[newIndexPath] withRowAnimation:UITableViewRowAnimationAutomatic];
            break;
        case NSFetchedResultsChangeDelete:
            [self.tableView deleteRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationAutomatic];
            break;
        case NSFetchedResultsChangeUpdate:
            [self.tableView reloadRowsAtIndexPaths:@[indexPath] withRowAnimation:UITableViewRowAnimationAutomatic];

        default:
            break;
    }
}

- (void)controllerDidChangeContent:(NSFetchedResultsController *)controller {

    [self.tableView endUpdates];
}

这是我的LocalDataManager.m：

#import "LocalDataManager.h"

@implementation LocalDataManager
@synthesize stack,fetchedResultController;

-(id)init{
    self = [super init];

    if (self) {
        //init
        stack = [CoreDataStack defaultStack];
        fetchedResultController = [self fetchedResultController];
        [self reloadData];
    }
    return self;
}

-(void)reloadData{
    [fetchedResultController performFetch:nil];
}
- (NSFetchRequest *)targetsFetchRequest {

    NSFetchRequest *fetchRequest = [NSFetchRequest fetchRequestWithEntityName:@"Target"];
    NSSortDescriptor *sortDescriptor = [[NSSortDescriptor alloc] initWithKey:@"time" ascending:NO];
    NSArray *sortDescriptors = [[NSArray alloc] initWithObjects:sortDescriptor, nil];
    [fetchRequest setSortDescriptors:sortDescriptors];
    return fetchRequest;
}


- (NSFetchedResultsController *)fetchedResultController {

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



    NSFetchRequest *fetchRequest = [self targetsFetchRequest];

    fetchedResultController = [[NSFetchedResultsController alloc] initWithFetchRequest:fetchRequest managedObjectContext:stack.managedObjectContext sectionNameKeyPath:nil cacheName:nil];

    fetchedResultController.delegate = self;

    return fetchedResultController;

}


@end

问题可能还在于表视图的最后3个方法，或者我从我的经理类而不是从表视图中拿着我的FetchResultController的事实，但我不知道直接指向它。。请帮我解决这个问题。

谢谢aallot！

Answer 1

从核心数据中删除记录后，您永远不会告诉表删除该行。

你需要：

- (void)tableView:(UITableView *)tableView commitEditingStyle:(UITableViewCellEditingStyle)editingStyle forRowAtIndexPath:(NSIndexPath *)indexPath {
    Target *target = [localDataManager.fetchedResultController objectAtIndexPath:indexPath];
    [[localDataManager.stack managedObjectContext] deleteObject:target];
    [localDataManager.stack saveContext];

    // Remove row from table
    [tableView deleteRowsAtIndexPaths:@[ indexPath ] withRowAnimation:UITableViewRowAnimationFade];

    if ([_delegate respondsToSelector:@selector(didDeleteObject)]) {
        [_delegate didDeleteObject];
    }
}

无法从表格视图中删除单元格

1 个答案: