ios - UITextField 不会将文本保存到 CoreData 中

Question

此 UITextField 以编程方式创建并驻留在自定义 UITableViewCell 中。 UITableViewCell 也是 UITextField 的委托(delegate)并实现 <UITextFieldDelegate>协议(protocol)。一切似乎都工作正常，除了当我重新加载应用程序时，没有任何文本保存在 CoreData 中。我尝试使 TableViewController 成为此类的委托(delegate)，但它似乎不起作用，实际上，由于发送到实例错误的无法识别的选择器，应用程序崩溃了。

这是我的 textFieldDidEndEditing 的代码方法:

- (void)textFieldDidEndEditing:(UITextField *)textField {

    Parts *item ; // the NSManagedObject

    item.itemTitle = _itemLabel.text; //_itemLabel is a custom UITextField Class, and itemTitle is a string attribute of the NSManagedObject


    NSError *error;
    [item.managedObjectContext save:&error];
    if (error) {
        // Replace this implementation with code to handle the error appropriately.
        // abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development.
        NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
        abort();
    }

}

这是自定义的部分init创建 UITextField 的方法:

_itemLabel = [[TehdaLabel alloc] initWithFrame:CGRectNull];
    _itemLabel.textColor = [UIColor blackColor];
    _itemLabel.font = [UIFont fontWithName:@"Helvetica" size:12];
    _itemLabel.backgroundColor = [UIColor clearColor];
    _itemLabel.contentVerticalAlignment = UIControlContentVerticalAlignmentCenter;
    _itemLabel.returnKeyType = UIReturnKeyDone;
    _itemLabel.placeholder = @"Type some stuff here!";
    _itemLabel.delegate = self;
    [self addSubview:_itemLabel];

其他一切都工作正常，将文本保存在 CoreData 中只是拒绝为我工作。

编辑:insertObject我的 TableViewController 中的方法

NSManagedObjectContext *context = [self.fetchedResultsController managedObjectContext];
Parts *item = [NSEntityDescription insertNewObjectForEntityForName:@"Parts" inManagedObjectContext:context];

    MCSwipeTableViewCell *editCell;
    for (MCSwipeTableViewCell *cell in [self.tableView visibleCells]){
        if (cell.itemLabel.text == item.itemTitle) {
        //if (cell.itemLabel.text == item.itemTitle) {
            editCell = cell;
            break;
        }
    }
    editCell.itemLabel.text = item.itemTitle;
    [editCell.itemLabel becomeFirstResponder];

    [item setValue:[NSDate date] forKey:@"itemDate"];

    // Save the context.
    NSError *error = nil;
    if (![context save:&error]) {
         // Replace this implementation with code to handle the error appropriately.
         // abort() causes the application to generate a crash log and terminate. You should not use this function in a shipping application, although it may be useful during development. 
        NSLog(@"Unresolved error %@, %@", error, [error userInfo]);
        abort();
    }

Answer 1

您没有将实体“Parts”插入 CoreData。

Parts *item = [NSEntityDescription insertNewObjectForEntityForName:@"Parts"
                                              inManagedObjectContext:managedObjectContext];

现在它将保存它......