RecyclerView onBindViewHolder 被无限次调用单个项目

Question

我正在构建一个聊天应用程序，在 聊天片段 我目前有一个聊天，其中有一条消息。问题是针对单个项目连续调用 onBindViewHolder。我发现了一个相关问题，它说问题是由 itemview 的布局参数引起的但是我对 itemview 的布局参数没有做任何事情。由于连续调用 onBindViewHolder 用于打开聊天的点击侦听器 activity 也无法正常工作。查看 Logcat 详细信息：

2019-03-08 00:48:54.464 1672-1672/com.invogen.messagingapp E/ChatAdapter: Message Key = -L_OWO_jaN6ggbeoAlmI
2019-03-08 00:48:54.474 1672-1672/com.invogen.messagingapp E/ChatAdapter: ChatPath = https://messagingapp-db3e5.firebaseio.com/Chats/-L_OWO_fra0oDMflLMTE/messages
2019-03-08 00:48:54.480 1672-1672/com.invogen.messagingapp E/ChatAdapter: Message Key = -L_OWO_jaN6ggbeoAlmI
2019-03-08 00:48:54.490 1672-1672/com.invogen.messagingapp E/ChatAdapter: ChatPath = https://messagingapp-db3e5.firebaseio.com/Chats/-L_OWO_fra0oDMflLMTE/messages
2019-03-08 00:48:54.497 1672-1672/com.invogen.messagingapp E/ChatAdapter: Message Key = -L_OWO_jaN6ggbeoAlmI
2019-03-08 00:48:54.507 1672-1672/com.invogen.messagingapp E/ChatAdapter: ChatPath = https://messagingapp-db3e5.firebaseio.com/Chats/-L_OWO_fra0oDMflLMTE/messages
2019-03-08 00:48:54.515 1672-1672/com.invogen.messagingapp E/ChatAdapter: Message Key = -L_OWO_jaN6ggbeoAlmI
2019-03-08 00:48:54.524 1672-1672/com.invogen.messagingapp E/ChatAdapter: ChatPath = https://messagingapp-db3e5.firebaseio.com/Chats/-L_OWO_fra0oDMflLMTE/messages
2019-03-08 00:48:54.532 1672-1672/com.invogen.messagingapp E/ChatAdapter: Message Key = -L_OWO_jaN6ggbeoAlmI
2019-03-08 00:48:54.540 1672-1672/com.invogen.messagingapp E/ChatAdapter: ChatPath = https://messagingapp-db3e5.firebaseio.com/Chats/-L_OWO_fra0oDMflLMTE/messages
2019-03-08 00:48:54.552 1672-1672/com.invogen.messagingapp E/ChatAdapter: Message Key = -L_OWO_jaN6ggbeoAlmI
2019-03-08 00:48:54.558 1672-1672/com.invogen.messagingapp E/ChatAdapter: ChatPath = https://messagingapp-db3e5.firebaseio.com/Chats/-L_OWO_fra0oDMflLMTE/messages
2019-03-08 00:48:54.568 1672-1672/com.invogen.messagingapp E/ChatAdapter: Message Key = -L_OWO_jaN6ggbeoAlmI
2019-03-08 00:48:54.575 1672-1672/com.invogen.messagingapp E/ChatAdapter: ChatPath = https://messagingapp-db3e5.firebaseio.com/Chats/-L_OWO_fra0oDMflLMTE/messages
2019-03-08 00:48:54.583 1672-1672/com.invogen.messagingapp E/ChatAdapter: Message Key = -L_OWO_jaN6ggbeoAlmI
2019-03-08 00:48:54.591 1672-1672/com.invogen.messagingapp E/ChatAdapter: ChatPath = https://messagingapp-db3e5.firebaseio.com/Chats/-L_OWO_fra0oDMflLMTE/messages
2019-03-08 00:48:54.600 1672-1672/com.invogen.messagingapp E/ChatAdapter: Message Key = -L_OWO_jaN6ggbeoAlmI
2019-03-08 00:48:54.608 1672-1672/com.invogen.messagingapp E/ChatAdapter: ChatPath = https://messagingapp-db3e5.firebaseio.com/Chats/-L_OWO_fra0oDMflLMTE/messages
2019-03-08 00:48:54.616 1672-1672/com.invogen.messagingapp E/ChatAdapter: Message Key = -L_OWO_jaN6ggbeoAlmI
2019-03-08 00:48:54.624 1672-1672/com.invogen.messagingapp E/ChatAdapter: ChatPath = https://messagingapp-db3e5.firebaseio.com/Chats/-L_OWO_fra0oDMflLMTE/messages
2019-03-08 00:48:54.631 1672-1672/com.invogen.messagingapp E/ChatAdapter: Message Key = -L_OWO_jaN6ggbeoAlmI
2019-03-08 00:48:54.642 1672-1672/com.invogen.messagingapp E/ChatAdapter: ChatPath = https://messagingapp-db3e5.firebaseio.com/Chats/-L_OWO_fra0oDMflLMTE/messages
2019-03-08 00:48:54.649 1672-1672/com.invogen.messagingapp E/ChatAdapter: Message Key = -L_OWO_jaN6ggbeoAlmI
2019-03-08 00:48:54.658 1672-1672/com.invogen.messagingapp E/ChatAdapter: ChatPath = https://messagingapp-db3e5.firebaseio.com/Chats/-L_OWO_fra0oDMflLMTE/messages
2019-03-08 00:48:54.740 1672-1672/com.invogen.messagingapp E/ChatAdapter: Message Key = -L_OWO_jaN6ggbeoAlmI

此过程在我退出应用程序之前不会停止。这是我的 firebase database 这个聊天节点的结构

下面是我的聊天片段代码，它调用 ChatAdapter

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    // Inflate the layout for this fragment
    View view = inflater.inflate(R.layout.fragment_chats, container, false);
    this.mContext = view.getContext();
    initViews(view);

    mChatsDBReference = FirebaseDatabase.getInstance().getReference().child(AppConstants.CHATS_NODE);
    fabCreate.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            // Floating Action Button's Action code here for creating new chat group
        }
    });

    LinearLayoutManager layoutManager = new LinearLayoutManager(getContext());
    mRecyclerView.setLayoutManager(layoutManager);
    mRecyclerView.setAdapter(new ChatAdapter(chatRoomChatsList, chatRoomKeysList));
    mChatsDBReference.addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
            chatRoomChatsList.clear();
            chatRoomKeysList.clear();
            if (dataSnapshot.exists()) {
                Log.e(TAG, "Snapshot Exits\nValue = " + dataSnapshot.toString());
                for (DataSnapshot ds : dataSnapshot.getChildren()) {
                    Chats chat = ds.getValue(Chats.class);

                    Log.e(TAG, "Chat Key = " + ds.getKey() + "\n DataSnapshot = " + ds.toString());
                    chatRoomChatsList.add(chat);
                    chatRoomKeysList.add(ds.getKey());
                }
            }
            mRecyclerView.getAdapter().notifyDataSetChanged();
        }
        @Override
        public void onCancelled(@NonNull DatabaseError databaseError) {
        }
    });

    return view;
}

这是我的ChatAdapterclass

public class ChatAdapter extends RecyclerView.Adapter<ChatViewHolder> {

private String TAG = "ChatAdapter";
private List<Chats> chatRoomChatsList;
private Context mContext;
//    private String pushKey;
private List<String> chatRoomChatsKeyList;
private List<FriendlyMessage> messageList;

public ChatAdapter(List<Chats> chatList, List<String> chatRoomChatsKeyList) {
    this.chatRoomChatsList = chatList;
 //        this.pushKey = pushKey;
    this.chatRoomChatsKeyList = chatRoomChatsKeyList;
}


@NonNull
@Override
public ChatViewHolder onCreateViewHolder(@NonNull ViewGroup viewGroup, int itemViewType) {

    View view = LayoutInflater.from(viewGroup.getContext()).inflate(R.layout.chats_layout,
            viewGroup, false);
    Log.e(TAG, "onCreateView LayoutId = " + itemViewType + " Inside MyLayout");

    return new ChatViewHolder(view);
}

@Override
public void onBindViewHolder(@NonNull final ChatViewHolder holder, int position) {
    mContext = holder.chatTitleTV.getContext();

    int pos = holder.getAdapterPosition();
    setupLastMessageData(holder);

    Chats chat = chatRoomChatsList.get(pos);
    String chatTitle = chat.getChatName();
    holder.chatTitleTV.setText(chatTitle);
    holder.avatarTV.setText(chatTitle);

    holder.itemView.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            String pushkey = chatRoomChatsKeyList.get(holder.getAdapterPosition());
            Log.e(TAG, "pushKey = " + pushkey);
            Bundle bundle = new Bundle();
            bundle.putString("pushKey", pushkey);
            Intent intent = new Intent(mContext, ChatMessagesActivity.class);
            intent.putExtras(bundle);

            mContext.startActivity(intent);
        }
    });

}

private void setupLastMessageData(final ChatViewHolder holder) {
    DatabaseReference mSingleChatReference =
            FirebaseDatabase.getInstance().getReference()
                    .child(AppConstants.CHATS_NODE)
                    .child(chatRoomChatsKeyList.get(holder.getAdapterPosition()))
                    .child("messages");
    Log.e(TAG, "ChatPath = " + mSingleChatReference);
    mSingleChatReference.addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(@NonNull DataSnapshot dataSnapshot) {
            messageList = new ArrayList<>();
            if (dataSnapshot.exists()) {
                for (DataSnapshot ds : dataSnapshot.getChildren()) {
                    FriendlyMessage msg = ds.getValue(FriendlyMessage.class);

                    Log.e(TAG, "Message Key = " + ds.getKey());
                    messageList.add(msg);
                }
            }
            holder.lastMessageTV.setText(messageList.get(messageList.size() - 1).getMsgText());
            holder.timeTV.setText(messageList.get(messageList.size() - 1).getMsgDate());
            notifyDataSetChanged();
        }

        @Override
        public void onCancelled(@NonNull DatabaseError databaseError) {

        }
    });
}

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

}

如果需要任何其他信息，请告诉我。任何帮助将不胜感激。

Answer 1

在您的 createView() 中，您正在调用 notifyDataSetChanged()，这会导致 RecyclerView 重新绑定并更新其所有内容。该过程的一部分包括调用 adapter.onBindViewHolder() 以将数据集绑定到构成列表的各个项目视图。但是在 adapter.onBindViewHolder() 中，您调用了 setupLastMessageData() ，它在内部再次调用 notifyDataSetChanged() ，它再次开始循环。这会创建 notify->bind->notify->bind

的无限循环

我的建议是让那些 firebase 侦听器位于适配器外部，侦听数据结构的必要更改和更新，并通过一次调用 notifyDataSetChanged() 将这些更改传递给适配器。如果您能够确定实际添加或更改了哪些消息，您甚至可以通过不调用 notifyDataSetChanged() 并从适配器调用更细化的 notifyXXX methods() 来提高效率。

RecyclerView onBindViewHolder 被无限次调用单个项目

RecyclerView onBindViewHolder is being called unlimited time for single item

android

adapter

android-fragments

firebase

android-recyclerview