导航到 Firestore 中的特定文档时如何显示 subСollection

Question

我在 Firestore 上有一个集合，里面有文档，它们显示在我的应用程序的 RecyclerView 中，我怎样才能使它在单击该文档时打开它的子​​集合？

当您单击文档时，会发生以下情况：

    private FirebaseFirestore firebaseFirestore = FirebaseFirestore.getInstance();
    private final CollectionReference collectionReference = firebaseFirestore.collection("Items");

    AdapterFactoryKeysSnap adapterFactoryKeysSnap;
    RecyclerView rv_keys_factory;
    RecyclerView.LayoutManager RLM_keys_factory;
    ProgressBar pb_keys_factory;

    private void RecyclerViewFactory() {
        Query query = collectionReference.orderBy("TurnKeyFactory", Query.Direction.DESCENDING);

        FirestoreRecyclerOptions<ItemKeys> firestoreRecyclerOptions = new FirestoreRecyclerOptions.Builder<ItemKeys>()
                .setQuery(query, ItemKeys.class).build();

        adapterFactoryKeysSnap = new AdapterFactoryKeysSnap((ClickKeysBlanc) getContext(), getContext(), firestoreRecyclerOptions);
        rv_keys_factory = requireView().findViewById(R.id.rv_keys_factory);
        RLM_keys_factory = new LinearLayoutManager(getActivity(), LinearLayoutManager.HORIZONTAL, false);
        SnapHelper snapHelper = new GravitySnapHelper(Gravity.START);
        snapHelper.attachToRecyclerView(rv_keys_factory);
        rv_keys_factory.setHasFixedSize(false);
        rv_keys_factory.setLayoutManager(RLM_keys_factory);
        rv_keys_factory.setNestedScrollingEnabled(true);
        rv_keys_factory.setAdapter(adapterFactoryKeysSnap);
        adapterFactoryKeysSnap.startListening();
        pb_keys_factory = requireView().findViewById(R.id.pb_keys_factory);
        Objects.requireNonNull(rv_keys_factory.getAdapter()).setStateRestorationPolicy(RecyclerView.Adapter.StateRestorationPolicy.PREVENT_WHEN_EMPTY);
        pb_keys_factory.setVisibility(View.GONE);
    }

应用程序了解由于“TurnKeyFactory”而单击了哪个文档。在这个文档里面是一个名为“TheKeyOpens”的子集合。

我找到了一种方法来实现本文档中的构想，我写了以下内容

“工厂退出键(Factory)”--名称文件

    private final FirebaseFirestore firebaseFirestore = FirebaseFirestore.getInstance();
    private final CollectionReference collectionReference = firebaseFirestore.collection("Items").document("Factory exit key(Factory)").collection("TheKeyOpens");

整个问题是，在我写完这个之后，它出现在主集合的所有文档中，而不是在特定的选择中。

我认为如果我的应用程序通过“TurnKeyFactory”打开选定的文档，如果我这样写，它将起作用：

    private final FirebaseFirestore firebaseFirestore = FirebaseFirestore.getInstance();
    private final CollectionReference collectionReference = firebaseFirestore.collection("Items").document("TurnKeyFactory").collection("TheKeyOpens");

但是没有用。帮忙解决问题。

需要

Items->
    - Factory exit key(Factory)->
        - TheKeyOpens->
            -TheKeyOpens 1
            -TheKeyOpens 2
            -TheKeyOpens 3
    - TurnKeyFactory: “1”

    - Factory exit key(Customs)->
        - TheKeyOpens->
            -TheKeyOpens 1
            -TheKeyOpens 2
            -TheKeyOpens 3
    - TurnKeyFactory: “2”

Answer 1

我认为如果我的应用程序通过“TurnKeyFactory”打开选定的文档，如果我这样写，它将起作用：

private final FirebaseFirestore firebaseFirestore = FirebaseFirestore.getInstance();
private final CollectionReference collectionReference = firebaseFirestore
    .collection("Items")
    .document("TurnKeyFactory")
    .collection("TheKeyOpens");

此引用不起作用，因为您将不正确的 ID 传递给 document() 方法。文档的 ID 应该是屏幕截图中的“Factory exit key(Factory)”而不是您实际添加的而不是“TurnKeyFactory”。为了使其工作，请使用以下参考：

private final CollectionReference collectionReference = firebaseFirestore
    .collection("Items")
    .document("Factory exit key(Factory)")
    .collection("TheKeyOpens");