如何从房间数据库中读取所有值并显示到recyclerview中? [英] how to read all value from room data base and show into recyclerview?

问题描述

我正在使用会议室数据库从URL存储json数据，但工作正常，但是在从数据库访问数据以在recyclerview上显示时，一次给出一个结果，如果我第二次打开应用程序，则显示第二个对象，我正在房间里的新物品可以有人建议我该怎么做，我的代码是. 应用我的pojo课. 我的适配器类是

I am using room database for storing json data from URL its working fine but while accessing data from data base to show on recyclerview its give one result at time and if i am open app second time then second object is showing, i am new in room can any one suggest me how to do this my code is. App my pojo class. My Adapter Class is.

   recyclerView = view.findViewById(R.id.recyclerView);
    postsAdapter = new PostsAdapter(new ArrayList<Example>());
    recyclerView.setLayoutManager(new LinearLayoutManager(getActivity()));
    addBorrowViewModel = ViewModelProviders.of(this).get(AddBorrowViewModel.class);
    addBorrowViewModel.getItemAndPersonList().observe(getActivity(), new Observer<List<Example>>() {
        @Override
        public void onChanged(@Nullable List<Example> itemAndPeople)
        {
            recyclerViewAdapter.addAll(itemAndPeople);
        }
    });

推荐答案

按照此

您没有在dao中添加LiveData.添加livedata，它将自动为您返回列表. 但是

You didn't add LiveData in your dao. Add livedata and it will automatically return the list for you. However

在你的身边

@Query("select * from table_name")
public LiveData<List<Model>> getAll();

在您的活动或片段中

 yourViewModel.getAll().observe(this, new Observer<List<Model>>() {
        @Override
        public void onChanged(@Nullable List<Model> models) {
            adapter.addAll(models);
        }
    });

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