Question

我在android中有会议室数据库。但是，当我从数据库中检索数据并显示在可展开的RecyclerView中时，它仅显示子列表中的最后一条记录。父母ArrayList下有一个孩子ArrayList。

我正在以hashmap的键和值格式添加ExpandableListView中来自数据库的数据

        HashMap<String, List<Movies>> expandableListDetail = new HashMap<String, List<Movies>>();
        ArrayList<String> moviecategoriess = new ArrayList<>();

        for (int i = 0; i < tasks.size(); i++) {
            childDataItems = new ArrayList<>();
            String movieCategory = tasks.get(i).getMovieCategory();

            String moviename = tasks.get(i).getMovieName();

            String description = tasks.get(i).getMovieDescription();
            String bannerimage = tasks.get(i).getMovieImage();
            //   String maincat=expandableListDetail.get("").get(i).
            childDataItems.add(new Movies(moviename, bannerimage, description));

            expandableListDetail.put(movieCategory, childDataItems);
            moviecategoriess.add(movieCategory);
        }

        Iterator it = expandableListDetail.entrySet().iterator();

        final ArrayList<MovieCategory> movieCategories = new ArrayList();

        moviesArrayList = new ArrayList();
        while (it.hasNext()) {
            Map.Entry pairs = (Map.Entry) it.next();
            String name = pairs.getKey().toString();
            moviesArrayList = (ArrayList<Movies>) pairs.getValue();

            movieCategories.add(new MovieCategory(name, moviesArrayList));
        }
        moviesAdapter = new MoviesAdapter(MovieActivity.this, movieCategories);
        Functions.setDatatoRecyclerView(rv_movies_list, moviesAdapter, MovieActivity.this);
        moviesAdapter.notifyDataSetChanged();
    }

我想像这样在ArrayList中显示数据

父项：惊悚片

列表中的ChildItems：

1）Force2

2）Sarkar2

父项：操作

列表中的ChildItems：

1）边框

2）战场

Answer 1

在您的情况下，每次循环运行时都存在for循环问题，根据您的代码会创建一个新的数组列表，因此只需用以下代码替换代码即可：

HashMap<String, List<Movies>> expandableListDetail = new HashMap<String, List<Movies>>();
        ArrayList<String> moviecategoriess = new ArrayList<>();
childDataItems = new ArrayList<>();
        for (int i = 0; i < tasks.size(); i++) {
            String movieCategory = tasks.get(i).getMovieCategory();

            String moviename = tasks.get(i).getMovieName();

            String description = tasks.get(i).getMovieDescription();
            String bannerimage = tasks.get(i).getMovieImage();
            //   String maincat=expandableListDetail.get("").get(i).
            childDataItems.add(new Movies(moviename, bannerimage, description));

            expandableListDetail.put(movieCategory, childDataItems);
            moviecategoriess.add(movieCategory);
        }

我正在尝试从arraylist的房间数据库中获取数据，但它仅显示android中的最后一条记录

1 个答案: