未觸發RecyclerView函式

我正在構建一個聊天應用程式。

我正在嘗試將來自 Firebase Firestore 的訊息顯示到 RecyclerView。

問題是，在我的配接器中，只有建構式執行。

這是我的聊天活動：

public class ChatActivity extends AppCompatActivity {

    public RecyclerView recyclerView;
    public ChatAdapter chatAdapter;
    public ArrayList<MessageChat> allMessages;
    public String userID;
    public FirebaseFirestore db;
    public MessageChat message;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_chat);

        userID = FirebaseAuth.getInstance().getUid();

        Intent intent = getIntent();
        Bundle b = intent.getExtras();

        recyclerView = findViewById(R.id.recyclerViewChatMessages);
        recyclerView.setLayoutManager(new LinearLayoutManager(getApplicationContext()));

        displayMessages(b.getString("matchID"));
    }

    public void displayMessages(String matchID) {

        db = FirebaseFirestore.getInstance();

        allMessages = new ArrayList<>();

        db.collection("messages")
                .whereIn("receiverUserID", Arrays.asList(userID, matchID))
                .addSnapshotListener(new EventListener<QuerySnapshot>() {
                    @Override
                    public void onEvent(@Nullable QuerySnapshot value,
                                        @Nullable FirebaseFirestoreException e) {
                        if (e != null) {
                            return;
                        }

                        allMessages.clear();
                        for (QueryDocumentSnapshot document : value) {
                            message = new MessageChat();
                            if (document.getString("senderUserID").equals(userID) || document.getString("senderUserID").equals(matchID)) {
                                message.content = document.getString("content");
                                message.date = (long) document.get("date");
                                message.receiverUserID = document.getString("receiverUserID");
                                message.senderUserID = document.getString("senderUserID");
                                allMessages.add(message);
                            }
                        } //here with debug I see that my messages are added into the list
                        chatAdapter = new ChatAdapter(getApplicationContext(), allMessages, userID);
                        recyclerView.setAdapter(chatAdapter);

                    }
                });

    }
}

還有我的聊天配接器

public class ChatAdapter extends RecyclerView.Adapter<RecyclerView.ViewHolder> {

    private Context currentContext;
    private ArrayList<MessageChat> listOfMessages;
    private String userID;
    private static final int LAYOUT_SENT = 1;
    private static final int LAYOUT_RECEIVED = 0;

    public ChatAdapter(Context cContext, ArrayList<MessageChat> cMessages, String cID) {
        this.currentContext = cContext;
        this.listOfMessages = cMessages;
        this.userID = cID;
// only this constructor is called, not the methods bellow
    }

    @Override
    public int getItemViewType(int position){
        Log.d("testiii", "get item view type");
        if (listOfMessages.get(position).senderUserID.equals(userID)){
            return LAYOUT_SENT;
        }
        else {
            return LAYOUT_RECEIVED;
        }
    }

    @NonNull
    @Override
    public RecyclerView.ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        if (viewType == LAYOUT_SENT){
            View view = LayoutInflater.from(currentContext).inflate(R.layout.message_item_sent, parent, false);
            return new ChatAdapter.SenderMessageViewHolder(view);
        }
        else {
            View view = LayoutInflater.from(currentContext).inflate(R.layout.message_item_received, parent, false);
            return new ChatAdapter.ReceiverMessageViewHolder(view);
        }
    }

    @Override
    public void onBindViewHolder(@NonNull RecyclerView.ViewHolder holder, int position) {
        if (getItemViewType(position) == LAYOUT_SENT){
            ((SenderMessageViewHolder) holder).sentMessage.setText(listOfMessages.get(position).content);
        }
        else {
            ((ReceiverMessageViewHolder) holder).receivedMessage.setText(listOfMessages.get(position).content);
        }
    }

    @Override
    public int getItemCount() {
        return listOfMessages.size();
    }

    public static class SenderMessageViewHolder extends RecyclerView.ViewHolder {

        public TextView sentMessage;
        public TextView sentDate;

        public SenderMessageViewHolder(@NonNull View itemView) {
            super(itemView);
            sentMessage = itemView.findViewById(R.id.textViewSentMessage);
            sentDate = itemView.findViewById(R.id.textViewSentDate);
        }

    }

    public static class ReceiverMessageViewHolder extends RecyclerView.ViewHolder {

        public TextView receivedMessage;
        public TextView receivedDate;

        public ReceiverMessageViewHolder(@NonNull View itemView) {
            super(itemView);
            receivedMessage = itemView.findViewById(R.id.textViewReceivedMessage);
            receivedDate = itemView.findViewById(R.id.textViewReceivedDate);
        }
    }

}

當我呼叫 displayMessages 時，我的訊息已正確添加到串列中，但我無法顯示它們。

你知道如何讓 RecyclerView 作業嗎？

uj5u.com熱心網友回復：

嘗試打電話chatAdapter.notifyDataSetChanged()后recyclerView.setAdapter(chatAdapter);

uj5u.com熱心網友回復：

實際上，在您的 ChatActivity 中，訊息串列正在傳遞給配接器，但您實際上并未將串列設定為布局管理器。嘗試使用 LinearLayoutManager 來顯示訊息。

https://developer.android.com/reference/androidx/recyclerview/widget/LinearLayoutManager?authuser=1

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