android - 如何从 Firestore 中检索数组？

Question

我正在使用数组数据结构来保存一些信息，如图所示

UserInfo.java

public class UserInfo {
private String userId, age, height;
public UserInfo(String userId, String age, String height) {
    this.userId = userId;
    this.age = age;
    this.height = height;
}
public String getUserId() {
    return userId;
}
public String getAge() {
    return age;
}
public String getHeight() {
    return height;
  }
}

如何获取 array1 和 array2 并将它们保存为 UserInfo 对象？ 因为我想填充 Recyclerview 中的数组。

Answer 1

首先您必须检索文档的内容。

一旦您成功检索到 DocumentSnapshot，然后从中获取 Java 对象并使用 Gson 将对象转换为 Json。

然后您可以解析 Json 并生成用户列表。现在您可以在 recyclerview 中填充列表。

FirebaseFirestore db;
List<UserInfo> userList;
@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_name);
    db = FirebaseFirestore.getInstance();

    userList = new ArrayList<>();
    DocumentReference docRef = db.collection("users").document("h3cj5y....");// you can use your own here
    docRef.get().addOnSuccessListener(new OnSuccessListener<DocumentSnapshot>() {
        @Override
        public void onSuccess(DocumentSnapshot documentSnapshot) {

            Object object = documentSnapshot.getData();
            String json = new Gson().toJson(object);
            Log.v("json",json);
            try {
                JSONObject infoObj=new JSONObject(json).getJSONObject("info");
                Iterator<String> iterator = infoObj.keys();
                while (iterator.hasNext()) {
                    String key = iterator.next();
                    JSONObject objArray=infoObj.getJSONObject(key);
                    UserInfo user=new UserInfo();
                    user.setAge(objArray.getString("age"));
                    user.setHeight(objArray.getString("height"));
                    user.setUserId(objArray.getString("userId"));
                    userList.add(user);
                }
            } catch (JSONException e) {
                e.printStackTrace();
            }

        }
    });
}

UserInfo.java

public class UserInfo {

private String age;
private String height;
private String userId;

public String getAge() {
    return age;
}

public void setAge(String age) {
    this.age = age;
}

public String getHeight() {
    return height;
}

public void setHeight(String height) {
    this.height = height;
}

public String getUserId() {
    return userId;
}

public void setUserId(String userId) {
    this.userId = userId;
}
}