带有 ViewModel 的 Android Hilt 范围为 Navgraph，Provider Factory 问题

Question

我正在使用 刀柄 对于 依赖注入(inject) 专门用于注入(inject)查看型号 .
还想范围 ViewModel 到 NavGraph .为此，请获取 ViewModelStoreOwner 通过 导航图 现在创建 查看型号 通过 导航图提供的存储实例至 ViewModelProvider .我面临的问题是，因为我只通过 存储实例 获取 ViewModelProvider 没有任何工厂 , 自 刀柄 将实现它，我得到构建错误 没有零参数构造函数 .当看到源代码时，我发现我只提供了 存储实例 作为论据，没有工厂，正在自动提供一个简单的工厂和 提供的工厂没有参数 ，因此出现此错误。
如何解决这个问题？
从源调用的方法 (ViewModelProvider.java) -

     * Creates {@code ViewModelProvider}. This will create {@code ViewModels}
     * and retain them in a store of the given {@code ViewModelStoreOwner}.
     * <p>
     * This method will use the
     * {@link HasDefaultViewModelProviderFactory#getDefaultViewModelProviderFactory() default factory}
     * if the owner implements {@link HasDefaultViewModelProviderFactory}. Otherwise, a
     * {@link NewInstanceFactory} will be used.
     */
    public ViewModelProvider(@NonNull ViewModelStoreOwner owner) {
        this(owner.getViewModelStore(), owner instanceof HasDefaultViewModelProviderFactory
                ? ((HasDefaultViewModelProviderFactory) owner).getDefaultViewModelProviderFactory()
                : NewInstanceFactory.getInstance());
    }

我的 ViewModel 类需要依赖注入(inject) -

    private Repository repository;
    private MutableLiveData<FeatureCollection> featureCollection = new MutableLiveData<>();
    private MutableLiveData<Boolean> loading = new MutableLiveData<>();
    private Disposable disposable;


    @ViewModelInject
    public QuakeListViewModel(Repository repository) {
        this.repository = repository;
    }

我的 fragment 课 -

    private FragmentQuakeListBinding _binding;
    private QuakeListViewModel _viewModel;
    private ViewModelStoreOwner viewModelStoreOwner;
    private NavController _navController;
 @Override
    public void onCreate(@Nullable Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        _navController = NavHostFragment.findNavController(this);
        viewModelStoreOwner =  _navController.getViewModelStoreOwner(R.id.main_nav_graph);

    }

public View onCreateView(@NotNull LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        //other implementation
        _viewModel = new ViewModelProvider(viewModelStoreOwner).get(QuakeListViewModel.class);
        //return binding.root
    }

任何帮助将不胜感激
谢谢

Answer 1

根据 Integration with the Jetpack navigation library documentation :

If your ViewModel is scoped to the navigation graph, use the defaultViewModelProviderFactory object that is available to activities and fragments that are annotated with @AndroidEntryPoint.

所以你可以使用:

_viewModel = new ViewModelProvider(viewModelStoreOwner,
    getDefaultViewModelProviderFactory()).get(QuakeListViewModel.class);