如何强制 Firestore Recycler Adapter 加载实时数据而不是从缓存中加载

Question

我希望 firestore recyclerview 适配器仅从服务器而不是缓存加载数据。 "I want the adapter display nothing if the device is offline." 但是我不知道怎么弄，就找了找。我发现的是在正常 get(); 方法中执行此操作的方法仅用于检索特定数据，但我没有找到任何人来解释使用 firebase firestore 适配器执行此操作的方法。

那是我的 MainActivity 代码。

public class MainActivity extends AppCompatActivity {
    private FirebaseFirestore db;
    RecyclerView recyclerView;
    private FirestoreRecyclerviewAdapter adapter;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main2);

        db=FirebaseFirestore.getInstance();

        //Query
        Query query = db.collection("collection");
        FirestoreRecyclerOptions<ItemClass> options=new FirestoreRecyclerOptions.Builder<ItemClass>()
                .setQuery(query, ItemClass.class)
                .build();

        recyclerView=findViewById(R.id.recycler);
        final LinearLayoutManager layoutManager = new LinearLayoutManager(MainActivity.this);

        adapter = new FirestoreRecyclerviewAdapter( options, this );

        recyclerView.setAdapter(adapter);
        recyclerView.setLayoutManager(layoutManager);

    }

    @Override
    protected void onStart() {
        super.onStart();
        adapter.startListening();
    }

    @Override
    protected void onStop() {
        super.onStop();
        adapter.stopListening();
    }

这是适配器 class... Firestore 适配器

public class FirestoreRecyclerviewAdapter  extends FirestoreRecyclerAdapter<ItemClass, FirestoreRecyclerviewAdapter.MyViewHolder> {

    public FirestoreRecyclerviewAdapter (@NonNull FirestoreRecyclerOptions<ItemClass> options) {
        super(options);
    }

    @Override
    protected void onBindViewHolder(@NonNull MyViewHolder holder, int position, @NonNull ItemClass item) {
        //Binding code.

    }

    @NonNull
    @Override
    public MyViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        return new MyViewHolder(LayoutInflater.from(parent.getContext()).inflate(R.layout.item, parent, false));
    }

    public class MyViewHolder extends RecyclerView.ViewHolder {
        //view components

        public MyViewHolder(@NonNull View itemView) {
            super(itemView);
            //initializing item components
        }
    }
}

Answer 1

我能想到的最简单的方法是 disabling disk persistence，您可以使用：

FirebaseFirestoreSettings settings = new FirebaseFirestoreSettings.Builder()
        .setPersistenceEnabled(false)
        .build();
db.setFirestoreSettings(settings);

Answer 2

当设备没有互联网连接时不要load/fetch数据，通知用户his/her设备离线，如果需要该服务应确保设备有互联网连接。

如何强制 Firestore Recycler Adapter 加载实时数据而不是从缓存中加载

How to force Firestore Recycler Adapter to load live data not from cache

android

firebase

android-recyclerview

firebaseui

google-cloud-firestore