我正在嘗試創建一種從我的Cloud Firestore database. 然后我會RecyclerView用上述列表設置一個適配器，它應該能很好地顯示。截止目前，RecyclerView空空如也。（我還RecyclerView用虛擬項目測試了它們，它們顯示得很好）在我的方法結束時，項目列表仍然是空的。日志以奇怪的順序顯示（最后一個日志顯示在其他日志之前）。日志順序讓我懷疑在偵聽器中運行了一些單獨的線程。我不確定如何同步它們。private List<Project> projects;private FirebaseFirestore db;...在onCreateView()（我正在處理一個片段）： db = FirebaseFirestore.getInstance(); queryAllProjects(); recyclerView.setAdapter(new ProjectRecyclerViewAdapter(projects, ...... private void queryAllProjects() {        projects = new ArrayList<>();         //I've already tried to make a local list and return that, however,         //the compiler would force me to declare the list as final here, and it wouldn't solve anything.        db.collection("projects")                .get()                .addOnCompleteListener(new OnCompleteListener<QuerySnapshot>() {                    @Override                    public void onComplete(@NonNull Task<QuerySnapshot> task) {                        if (task.isSuccessful()) {                            for (QueryDocumentSnapshot document : task.getResult()) {                                Log.d(TAG, document.getId() + " => " + document.getData());                                Project project = document.toObject(Project.class);                                projects.add(project);                            }                            Log.d(TAG, "After for loop: " + projects.toString());                             //Here the list is OK. Filled with projects.                             //I'd like to save the state of the list from here                        } else {                            Log.d(TAG, "Error getting document: ", task.getException());                            Toast.makeText(getContext(), R.string.error, Toast.LENGTH_SHORT).show();                        }                    }                });這是我一直在關注的官方文檔https://firebase.google.com/docs/firestore/query-data/get-data#custom_objects