ios - 从 data core ios 获取数据

Question

我正在开发 ios 应用程序，当单击添加按钮时，它会将我带到另一个 View Controller 以填充我的信息并将它们保存在核心数据中如何获取此数据并将其发布到 Tableview 中有什么帮助吗？

Answer 1

保存数据(在您获取数据的 View Controller 中)

在你的.m文件中添加

- (NSManagedObjectContext *)managedObjectContext
{
    NSManagedObjectContext *context = nil;
    id delegate = [[UIApplication sharedApplication] delegate];
    if ([delegate performSelector:@selector(managedObjectContext)]) {
        context = [delegate managedObjectContext];
    }
    return context;
}

并在您的保存操作中添加

- (IBAction)savePressed:(id)sender
{
    NSManagedObjectContext *context = [self managedObjectContext];

        NSManagedObject *newData = [NSEntityDescription insertNewObjectForEntityForName:@"StoredData" inManagedObjectContext:context];

        [newData setValue:textField.text forKey:@"dataattribute"];

    NSError *error = nil;

    if (![context save:&error]) {
        NSLog(@"Save Failed! %@ %@", error, [error localizedDescription]);
    }

}

在表格 View Controller 中

- (NSManagedObjectContext *)managedObjectContext
{
    NSManagedObjectContext *context = nil;
    id delegate = [[UIApplication sharedApplication] delegate];
    if ([delegate performSelector:@selector(managedObjectContext)]) {
        context = [delegate managedObjectContext];
    }
    return context;
}

在你看来确实出现了

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

    NSManagedObjectContext *moc = [self managedObjectContext];
    NSFetchRequest *fetchRequest = [[NSFetchRequest alloc] initWithEntityName:@"entityName"];
    arrayData = [[moc  executeFetchRequest:fetchRequest error:nil] mutableCopy];


    [self.tableView reloadData];
}

在你的 cellForRowAtIndexPath

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

    static NSString *cellIdentifier = @"Cell";
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:cellIdentifier forIndexPath:indexPath];

    // Configure the cell...
    NSManagedObject *data = [arrayData objectAtIndex:indexPath.row];

    [cell.textLabel setText:[NSString stringWithFormat:@"%@", [data valueForKey:@"dataattribute"]]];

    return cell;
}