如何在安卓系统中从FireStore中检索用户数据

FirebaseFirestore db = FirebaseFirestore.getInstance();

CollectionReference usersRef = db.collection("users");

DocumentReference userRef = db.collection("users").document("john_doe");

userRef.get().addOnSuccessListener(new OnSuccessListener<DocumentSnapshot>() {
    @Override
    public void onSuccess(DocumentSnapshot documentSnapshot) {
        if (documentSnapshot.exists()) {
            // 文档存在，可以获取数据
            String name = documentSnapshot.getString("name");
            int age = documentSnapshot.getLong("age").intValue();
            // 处理数据
        } else {
            // 文档不存在
        }
    }
});

usersRef.whereEqualTo("age", 25).get().addOnSuccessListener(new OnSuccessListener<QuerySnapshot>() {
    @Override
    public void onSuccess(QuerySnapshot querySnapshot) {
        for (QueryDocumentSnapshot documentSnapshot : querySnapshot) {
            // 处理每个文档的数据
            String name = documentSnapshot.getString("name");
            int age = documentSnapshot.getLong("age").intValue();
        }
    }
});