Android 访问firebase回收器适配器中的子节点

我有我的

firebaseRecyclerAdapter

，它的

populateViewHolder

如下

Query queryRef = chatRef.orderByKey();
queryRef.addChildEventListener(new ChildEventListener() {
    @Override
    public void onChildAdded(DataSnapshot snapshot, String previousChild) {
        System.out.println(snapshot.getKey());

        for (DataSnapshot snapshot1 : snapshot.getChildren()) {
            final String firstname = snapshot.getKey();
            chatViewHolder.setName(firstname);

            chatViewHolder.mView.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View view) {
                    //Log.w(TAG, "You clicked on "+position);
                    //String firstname = tList.getFirstname();
                    //String lastname = tList.getLastname();
                    //firstname = firstname.substring(0, 1).toUpperCase() + firstname.substring(1); //convert first string to uppercase
                    //lastname = lastname.substring(0, 1).toUpperCase() + lastname.substring(1);// same thing happening here
                    //String name = (firstname + " " + lastname); // concatenate firstname and lastname variable.

                    Intent intent = new Intent(getActivity(), MainChat.class); //change to onclick
                    intent.putExtra("fullname", firstname);
                    //you can name the keys whatever you like
                    //intent.putExtra("image", userList.getImgUrl().toString()); //note that all these values have to be primitive (i.e boolean, int, double, String, etc.)
                    startActivity(intent);

                }
            });
        }

这是用回收器适配器备份的，我的数据库看起来像

users
   uid
      conversations
                   sLname + sFname
                           -KyF........:
                                  message: hi
                                  timestamp: ServerValue.timestamp
                            -KyFr......:
                                  message:hello
                                  timestamp: ServerValue.timestamp

firebaseRecyclerAdapter的实现

RecyclerView recycler = (RecyclerView) rootView.findViewById(R.id.recyclerview4);
recycler.setHasFixedSize(true);
recycler.setLayoutManager(new LinearLayoutManager(getActivity()));


FirebaseRecyclerAdapter mAdapter = new FirebaseRecyclerAdapter<ChatList, ChatHolder>(ChatList.class, R.layout.chatlistrow, ChatHolder.class, chatRef) {
    @Override
    public void populateViewHolder(final ChatHolder chatViewHolder, final ChatList chatList, final int position) {

        //try catch block to catch events of no posts, it will most likely return a null error, so I'm catching it, else
        //find its exception and catch itef

        contactList = new ArrayList<String>();

         //start here and getkey for everyone

        contactList.add(chatRef.getKey());

        //String firstname = chatRef.getKey();
        //chatViewHolder.setName(firstname);

        Query queryRef = chatRef.orderByKey();
        queryRef.addChildEventListener(new ChildEventListener() {
            @Override
            public void onChildAdded(DataSnapshot snapshot, String previousChild) {
                System.out.println(snapshot.getKey());

                for (DataSnapshot snapshot1 : snapshot.getChildren()) {
                    final String firstname = snapshot.getKey();
                    chatViewHolder.setName(firstname);

                    chatViewHolder.mView.setOnClickListener(new View.OnClickListener() {
                        @Override
                        public void onClick(View view) {
                            //Log.w(TAG, "You clicked on "+position);

                            Intent intent = new Intent(getActivity(), MainChat.class); //change to onclick
                            intent.putExtra("fullname", firstname);
                            //you can name the keys whatever you like
                            //intent.putExtra("image", userList.getImgUrl().toString()); //note that all these values have to be primitive (i.e boolean, int, double, String, etc.)
                            startActivity(intent);
                        }
                    });
                }
                //testing
            }

            @Override
            public void onChildChanged(DataSnapshot snapshot, String previousChild) {
            }

            @Override
            public void onChildMoved(DataSnapshot snapshot, String previousChild) {
            }

            @Override
            public void onChildRemoved(DataSnapshot snapshot) {
            }

            @Override
            public void onCancelled(DatabaseError databaseError) {
            }
            // ....
        });
    }
};
recycler.setAdapter(mAdapter);

class（）指向此处

package com.mordred.theschoolapp;

/**
 * Created by mordred on 11/29/16.
 */
public class ChatList {

    public String userId;
    public String rname;
    public String rlastname;
    public String rimageurl;

    public ChatList() {
        // Default constructor required for calls to DataSnapshot.getValue(User.class)
    }

    public String getFirstname() {
        return rname;
    }

    public void setFirstname(String firstname) {
        this.rname = firstname;
    }

    public String getLastname() {
        return rlastname;
    }

    public void setLastname(String lastname) {
        this.rlastname = lastname;
    }

    public String getImgUrl() {
        return rimageurl;
    }

    public void setImgUrl(String imgUrl) {
        this.rimageurl = imgUrl;
    }

    public String getUserId() {
        return userId;
    }

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

这里的问题是，我试图在回收器适配器中递归地检索这些消息。 但是由于前面的代码在上面，我只是不断地重复第一条消息。

---

有人能告诉我发生了什么事，我怎样才能修复它吗？如果你需要更多的信息，尽管问。谢谢

看起来您不明白

Firebase UI数据库

是如何工作的。完整的文档是，您应该阅读该自述文件以了解其工作原理

populateViewHolder

方法的工作原理与

onchildaded/onChildChanged

几乎相同，它返回引用节点下的每个子节点

所以应该是这样的

chatRef = FirebaseDatabase.getInstance().getReference("users").child(uid).child("conversations");

...

@Override
public void populateViewHolder(final ChatHolder chatViewHolder, final ChatList chatList, final int position) {
    contactList = new ArrayList<String>();
    // this is what you want
    String fullName = mAdapter.getRef(position).getKey();
    contactList.add(fullName);

    ...
}

chatRef=FirebaseDatabase.getInstance（）.getReference（“用户”）.child（uid）.child（“对话”）； ... @凌驾 public void populateViewHolder（最终聊天室持有者聊天室视图持有者、最终聊天室列表聊天室列表、最终int位置）{ contactList=新的ArrayList（）； //这就是你想要的 字符串fullName=mAdapter.getRef（position.getKey（）； 联系人列表。添加（全名）； ... }

---

顺便说一下，您的

ChatList

模型类缺少属性，或者属性没有反映数据库中的键，因此某些方法可能返回

null

值

我不明白你的问题是什么。您能否发布

FirebaseRecyclerAdapter

的实现，指出适配器侦听数据库的节点，以及

chatRef

指向的位置。另外，您在数据库中的

sLname+sFname

是什么意思？最好发布它的确切JSON格式，只需从Firebase数据库控制台导出JSON即可。谢谢，我刚刚更新了我的问题，所以

chatRef

指向此节点

users///conversations///code>？是的，它指向这里非常感谢。但我完全理解如何做到这一点，但这里的问题是，这不是我想要返回的，我想要返回对话的直接子对象。不是那些。那么
chatRef
指向的是
用户//对话//
不是
用户//对话//
@Mordredeyes，我想回复每一次谈话，谢谢。我正要把你的答案标记为正确，但我注意到mAdapter一直说firebaseRecyclerAdapter需要被宣布为最终版本。当我宣布它是最终的，它说它从未初始化过
chatRef = FirebaseDatabase.getInstance().getReference("users").child(uid).child("conversations");

...

@Override
public void populateViewHolder(final ChatHolder chatViewHolder, final ChatList chatList, final int position) {
    contactList = new ArrayList<String>();
    // this is what you want
    String fullName = mAdapter.getRef(position).getKey();
    contactList.add(fullName);

    ...
}