在android studio中引用Firestore

落花踏尽游何处，笑入胡姬酒肆中。这篇文章主要讲述在android studio中引用Firestore相关的知识，希望能为你提供帮助。
我有一些问题，引用一个特定的集合是嵌套的（我认为这个术语），我已经附上了我的数据库结构的图像如下。

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编辑：食品系列的图片

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我基本上有多个文档，里面有一个同名的集合。有没有一种方法可以让我根据用户在前一页点击的餐厅ID动态选择 "食品 "集合，即如果用户选择了ID为01的餐厅，就应该从ID为01的文档中加载 "食品"，等等。
【在android studio中引用Firestore】以下是我的代码，用于加载食品的片段。

import android.content.Context; import android.net.Uri; import android.os.Bundle; import androidx.annotation.NonNull; import androidx.annotation.Nullable; import androidx.fragment.app.Fragment; import androidx.recyclerview.widget.LinearLayoutManager; import androidx.recyclerview.widget.RecyclerView; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import com.example.hostapp.Adapters.FoodAdapter; import com.example.hostapp.Models.FoodModel; import com.example.hostapp.R; import com.firebase.ui.firestore.FirestoreRecyclerOptions; import com.google.firebase.firestore.CollectionReference; import com.google.firebase.firestore.FirebaseFirestore; import com.google.firebase.firestore.Query; public class MainsFragment extends Fragment {private FirebaseFirestore db = FirebaseFirestore.getInstance(); private CollectionReference menuref = db.collection("Foods"); private FoodAdapter adapter; String restaurantid = ""; @Nullable @Override public View onCreateView(@NonNull LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) { View view = inflater.inflate(R.layout.fragment_mains, container, false); Query query = menuref.whereEqualTo("menuid", restaurantid).orderBy("name"); FirestoreRecyclerOptions< FoodModel> options = new FirestoreRecyclerOptions.Builder< FoodModel> (). setQuery(query, FoodModel.class) .build(); adapter = new FoodAdapter(options); RecyclerView recyclerView = view.findViewById(R.id.recycler_mains); recyclerView.setHasFixedSize(true); recyclerView.setLayoutManager(new LinearLayoutManager(this.getActivity())); recyclerView.setAdapter(adapter); return view; }private void setUpRecyclerView() {}@Override public void onStart() { super.onStart(); adapter.startListening(); }@Override public void onStop() { super.onStop(); adapter.stopListening(); } }

对于前一个页面的点击，

import androidx.appcompat.app.AppCompatActivity; import androidx.recyclerview.widget.LinearLayoutManager; import androidx.recyclerview.widget.RecyclerView; import android.app.Activity; import android.content.Intent; import android.os.Bundle; import android.widget.RelativeLayout; import com.example.hostapp.Adapters.RestaurantAdapter; import com.example.hostapp.Adapters.categoryCardAdapter; import com.example.hostapp.Models.Restaurant; import com.example.hostapp.Models.categoryCard; import com.firebase.ui.firestore.FirestoreRecyclerOptions; import com.google.firebase.firestore.CollectionReference; import com.google.firebase.firestore.DocumentSnapshot; import com.google.firebase.firestore.FirebaseFirestore; import com.google.firebase.firestore.Query; public class RestaurantList extends AppCompatActivity {private FirebaseFirestore db = FirebaseFirestore.getInstance(); private CollectionReference restaurantref = db.collection("restaurants"); private RestaurantAdapter adapter; String categoryid=""; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_restaurant_list); setUpRecyclerView(); }private void setUpRecyclerView(){//Get intent if(getIntent() != null) categoryid = getIntent().getStringExtra("categoryid"); if(!categoryid.isEmpty() & & categoryid != null) { Query query = restaurantref.whereEqualTo("categoryid", categoryid).orderBy("name"); final FirestoreRecyclerOptions< Restaurant> options = new FirestoreRecyclerOptions.Builder< Restaurant> ().setQuery(query, Restaurant.class).build(); adapter = new RestaurantAdapter(options); RecyclerView recyclerView = (RecyclerView) findViewById(R.id.restaurant_recycler); recyclerView.setHasFixedSize(true); recyclerView.setLayoutManager(new LinearLayoutManager(this)); recyclerView.setAdapter(adapter); adapter.setOnItemClickListerner(new RestaurantAdapter.OnItemClickListener() { @Override public void onItemClick(DocumentSnapshot documentSnapshot, int position) { Restaurant restaurant = documentSnapshot.toObject(Restaurant.class); Intent foodlist = new Intent(RestaurantList.this, Foodlist.class); foodlist.putExtra("restaurantid", documentSnapshot.getId()); startActivity(foodlist); } }); } }@Override protected void onStart() { super.onStart(); adapter.startListening(); }@Override protected void onStop() { super.onStop(); adapter.stopListening(); } }

答案根据你的意见，要得到所有 Food 所有子库中存在的文件，根据 "文件管理 "的要求，将其归入 "文件管理 "的范畴。menuid 财产，a 火库收藏组查询是需要的。这个查询是这样的。