[java]如何在片段中正确设置回收器视图

· 收录于 2023-09-24 05:29:11 · source URL

问题详情

我

想知道我应该如何在我的片段中正确设置我的回收器视图，dashboardViewModel 观察文本字段，但我还没有找到如何观察回收器视图，所以我只是绑定它并设置了一个适配器，但我认为我的方式错了。

// My Dashboard fragment :
    public View onCreateView(@NonNull LayoutInflater inflater,
                             ViewGroup container, Bundle savedInstanceState) {
        DashboardViewModel dashboardViewModel =
                new ViewModelProvider(this).get(DashboardViewModel.class);

        binding = FragmentDashboardBinding.inflate(inflater, container, false);
        View root = binding.getRoot();

        final TextView textView = binding.textDashboard;
        dashboardViewModel.getText().observe(getViewLifecycleOwner(), textView::setText);

        RecyclerView recyclerView = binding.recyclerView;
        DummyDatas dummyDatas = new DummyDatas();
        ProductAdapter productAdapter = new ProductAdapter(dummyDatas.getProducts());
        recyclerView.setAdapter(productAdapter);

        return root;

// My Dash board view Model

    public DashboardViewModel() {
        mText = new MutableLiveData<>();
        mProducts = new MutableLiveData<>();

        DummyDatas dummyDatas = new DummyDatas();
        List<Product> products = dummyDatas.getProducts();

        double totalBasketPrice = 0.0;

        for (Product product : products){
            System.out.println(product.getPriceAtUnit());
            totalBasketPrice = totalBasketPrice + product.getPriceAtUnit();
        }

        mProducts.setValue(products);

        mText.setValue("Price :" + totalBasketPrice);
    }

    public LiveData<String> getText() {
        return mText;
    }

    public LiveData<List<Product>> getProducts() {
        return mProducts;
    }
    }

最佳回答

您可以使用 LiveData.observe（） 函数中的适配器更新 RecyclerView 数据。

public View onCreateView(@NonNull LayoutInflater inflater,
                             ViewGroup container, Bundle savedInstanceState) {
    DashboardViewModel dashboardViewModel =
                new ViewModelProvider(this).get(DashboardViewModel.class);

    binding = FragmentDashboardBinding.inflate(inflater, container, false);
    View root = binding.getRoot();

    final TextView textView = binding.textDashboard;
    dashboardViewModel.getText().observe(getViewLifecycleOwner(), textView::setText);

    RecyclerView recyclerView = binding.recyclerView;
    DummyDatas dummyDatas = new DummyDatas();
    final ProductAdapter productAdapter = new ProductAdapter(dummyDatas.getProducts());
    recyclerView.setAdapter(productAdapter);

    // observe products and update data using adapter's data functions
    // either replace the whole list, or use DiffUtil
    dashboardViewModel.getProducts().observe(getViewLifecycleOwner(), products -> {
        productAdapter.setProducts(products);
        productAdapter.notifyDataSetChanged();
    });
    return root;
}