Ios 如何更新我的核心数据字段。我什么时候做了一些改变？

这是我的两种方法，当用户选中或取消选中表视图时，我需要更新

核心数据中的复选标记。我尝试了很多方法，但无法使用代码更新数据

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *CellIdentifier = @"cell";
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];

    cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier];

    UIButton *testButton = [[UIButton alloc]initWithFrame:CGRectMake(5, 5, 40, 40)];
    [testButton setImage:[UIImage imageNamed:@"oval"] forState:UIControlStateNormal];
    [testButton setImage:[UIImage imageNamed:@"tick"] forState:UIControlStateSelected];
    [testButton addTarget:self action:@selector(buttonTouched:) forControlEvents:UIControlEventTouchUpInside];

    [cell addSubview:testButton];
    [cell setIndentationLevel:1];
    [cell setIndentationWidth:45];
    cell.selectionStyle = UITableViewCellSelectionStyleNone;

    // Configure the cell...
    NSManagedObject *note = [self.notes objectAtIndex:indexPath.row];

    NSDate *date = [note valueForKey:@"mod_time"];
    NSString *dateString = [formatter stringFromDate:date];


    cell.textLabel.text = [note valueForKey:@"title"];
    cell.detailTextLabel.text = dateString;

    return cell;

}

这是我的按钮检查方法。我需要在核心字段中保存数据

-(void)buttonTouched:(id)sender
{
  UIButton *btn = (UIButton *)sender;

  if( [[btn imageForState:UIControlStateNormal] isEqual:[UIImage imageNamed:@"oval"]]) {
    //[tableView deselectRowAtIndexPath:indexPath animated:YES];
    [btn setImage:[UIImage imageNamed:@"tick"] forState:UIControlStateNormal];
   } else {
     [btn setImage:[UIImage imageNamed:@"oval"] forState:UIControlStateNormal];
   }
  }

好的，做一件事，转到核心数据，创建另一个名为check的属性，类型应该是string

然后转到顶部菜单栏->编辑器->nsmanageobjectsubclass并在project中创建它们

在那之后做这个

- (UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
    static NSString *CellIdentifier = @"cell";
    UITableViewCell *cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];


        cell = [[UITableViewCell alloc] initWithStyle:UITableViewCellStyleSubtitle reuseIdentifier:CellIdentifier];


    cell.selectionStyle = UITableViewCellSelectionStyleNone;

      FilterButton *testButton = [[FilterButton alloc]initWithFrame:CGRectMake(5, 5, 40, 40)];
    UIImageView*sideImage=[[UIImageView alloc] initWithFrame:CGRectMake(5, 5, 40, 40)];

    // Configure the cell...
    Notes*note=(Notes*)[[self fetchedResultsControllerCate] objectAtIndexPath:indexPath];

    NSDate *date =note.mod_time;

        NSString *dateString = [formatter stringFromDate:date];
    if([note.check isEqualToString:@"yes"]){

        [sideImage setImage:[UIImage imageNamed:@"tick"]];

    }else{

   // [testButton setImage:[UIImage imageNamed:@"oval"] forState:UIControlStateNormal];

        [sideImage setImage:[UIImage imageNamed:@"oval"]];
    // NSLog(@" write no");
    }

     testButton.myDate=note.mod_time;
    cell.textLabel.text = note.title;

    cell.detailTextLabel.text = dateString;
     [testButton addTarget:self action:@selector(buttonTouched:) forControlEvents:UIControlEventTouchUpInside];

     [cell setIndentationLevel:1];
    [cell setIndentationWidth:45];
    [cell.contentView addSubview:sideImage];
    [cell.contentView addSubview:testButton];



    return cell;

}

在上面的代码中，我只是尝试从cordite获取状态以显示复选框图像，然后我在第二个方法中更新状态，因此当用户在check或uncheck上单击时，我们触发此方法并更新coredata中的列名check。但是，是的，我使用的是fetchviewcontroler及其委托，它简单地直接获取任何更新，所以在这方面我们不需要做太多的工作

-(void)buttonTouched:(id)sender

{
        FilterButton *btn = (FilterButton *)sender;


    NSManagedObjectContext *context = [self managedObjectContext];
    Notes * NotesUpdateing;

    NSFetchRequest *request= [[NSFetchRequest alloc] init];
    NSEntityDescription *entity = [NSEntityDescription entityForName:@"Notes" inManagedObjectContext:context];
    NSPredicate *predicate =[NSPredicate predicateWithFormat:@"mod_time==%@",btn.myDate];
   // NSLog(@"btn.myDate   ..%@",btn.myDate);
    [request setEntity:entity];
    [request setPredicate:predicate];


    NSError *error = nil;

    // Below line is giving me error

    NSArray *array = [context executeFetchRequest:request error:&error];

    if (array != nil) {
        NSUInteger count = [array count]; // may be 0 if the object has been deleted.
        if(count==0){

            NSLog(@"nothing  to updates");



        }else{
           NotesUpdateing = (Notes*)[array objectAtIndex:0];

            if ([NotesUpdateing.check isEqualToString:@"no"]) {


            NotesUpdateing.check=@"yes";
             NSLog(@" write yes");
                btn.selected=NO;

            }
            else
            {
                NotesUpdateing.check=@"no";
                btn.selected=NO;
                 NSLog(@" write no");

            }

        }
    }
    if (![context save:&error]) {
        NSLog(@"Can't Save! %@ %@", error, [error localizedDescription]);
    }
    [self.tableView reloadData];






    }

更改后，从模拟器或设备中删除应用程序并重新编译