iphone - 检查基于 PFRelation 的 PFTableViewCell

Question

我在类别和项目之间有一个 PRelation 我希望制作一个 PFQueryTableViewController 用于将项目添加到类别。 PFQueryTableViewController 列出所有项目，用户选择要放入类别中的项目。我想弄清楚的是如何确定该项目是否在类别中并将 PFTableViewCell accessoryType 设置为 UITableViewCellAccessoryCheckmark

当前代码:

- (PFTableViewCell*)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath object:(PFObject *)object {

    static NSString * CellIdentifier = @"Cell";

    BOOL itemInCategory = ?; //This is where I am determining the hierarchy

    PFTableViewCell * cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    cell.textLabel.text = [sendingObject valueForKey:@"Title"];
    cell.accessoryType = itemInCategory ? UITableViewCellAccessoryCheckmark : UITableViewCellAccessoryNone;
    return cell;

}

编辑

我还需要一些帮助从类别中删除项目:

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

    BOOL itemInCategory = ?;

    if (itemInCategory) {

        //Remove Item?

    } else {
        PFRelation * relation = [sendingObject relationforKey:@"Items"];
        [relation addObject:[self.objects objectAtIndex:[indexPath row]]];
        [self save];
    }

}

应该很简单

干杯

Answer 1

我遇到过类似的情况。我制作了一个容器来保存选定的 indexPaths。

@property (nonatomic, strong) NSMutableArray*selectedIndexPaths;

初始化选择容器

- (void)viewDidLoad
{
    self.selectedIndexPaths = [@[] mutableCopy];
}

检查特定的indexPath是否存储在选择容器数组中

- (PFTableViewCell*)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath object:(PFObject *)object {

    static NSString * CellIdentifier = @"Cell";

    BOOL itemInCategory = [self.selectedIndexPaths containsObject:indexPath];

    PFTableViewCell * cell = [tableView dequeueReusableCellWithIdentifier:CellIdentifier];
    cell.textLabel.text = [sendingObject valueForKey:@"Title"];
    cell.accessoryType = itemInCategory ? UITableViewCellAccessoryCheckmark : UITableViewCellAccessoryNone;
    return cell;

}

如果 indexPath 存储在选择数组中，则从关系中删除项目，否则添加它并重新加载 tableView。

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

       BOOL itemInCategory = [self.selectedIndexPaths containsObject:indexPath];
       PFRelation * relation = [sendingObject relationforKey:@"Items"];

       if (itemInCategory) {

           //Remove the item from selectedIndex container and also relation
           [self.selectedIndexPaths removeObject:indexPath];
           [relation removeObject:self.objects[indexPath.row]];

       } 
       else {

           [self.selectedIndexPaths addObject:indexPath];
           [relation addObject:self.objects[indexPath.row]];
           [self save];
       }

       [tableView reloadData];

   }