Question

它是一个简单的客户端查询聊天应用程序。我能够在firebase中插入数据并通过解析tsp页面来获取所需的数据（这是一个临时安排，有人正在制作一个将返回json数据的api）。我无法在Recycler视图中显示我的firebase数据。我能够在数据库中插入数据。在scree上只显示null / 0/0。

以下是我的活动代码：

public class VD extends AppCompatActivity {
    private EditText ed;
    private String content;
    private RecyclerView recyclerView;
    String chatId;
    DatabaseReference myRef;

    private FirebaseDatabase database;
    private final List<Messages> mList = new ArrayList<>();

    @Override
    protected void onCreate(Bundle savedInstanceState) {

        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_vd);
        ed = findViewById(R.id.editText);
        //gets you the contents of edit text
        //


        database = FirebaseDatabase.getInstance();
        /*myRef = database.getReference("message");

        myRef.setValue("Hello vcbv World!");*/
    }

    @Override
    protected void onPause() {
        super.onPause();
        database.getReference("onlineStatus").child("status").setValue("n");
    }

    @Override
    protected void onResume() {
        super.onResume();
        database.getReference("onlineStatus").child("status").setValue("y");
    }


    public void updateDatabase(View view) {
        content = ed.getText().toString();
        //Log.d("vidhu",content);
        String[] cd = content.split("/");
        final String caseType = cd[0];
        final int caseNumber = Integer.parseInt(cd[1]);
        final int caseYear = Integer.parseInt(cd[2]);


        myRef = database.getReference("case_details");
        chatId = myRef.push().getKey();
        CaseDetails caseDetails = new CaseDetails(caseType, caseNumber, caseYear);
        myRef.child(chatId).setValue(caseDetails);
        myRef.child(chatId).child("status").setValue("");
        VD.JsoupAsyncTask jsoupAsyncTask = new VD.JsoupAsyncTask();
        jsoupAsyncTask.execute();

        myRef.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(DataSnapshot dataSnapshot) {
                for(DataSnapshot ds : dataSnapshot.getChildren()) {
                    Messages a = dataSnapshot.getValue(Messages.class);
                    mList.add(a);
                }

                    recyclerView = findViewById(R.id.recycler_view);

                    MessagePopulator mAdapter = new MessagePopulator(mList);
                    recyclerView.setAdapter(mAdapter);
                    mAdapter.notifyDataSetChanged();
                    RecyclerView.LayoutManager mLayoutManager = new LinearLayoutManager(getApplicationContext());
                    recyclerView.setLayoutManager(mLayoutManager);
                    recyclerView.setItemAnimator(new DefaultItemAnimator());

            }

            @Override
            public void onCancelled(DatabaseError databaseError) {

            }
        });

        /*myRef.addChildEventListener(new ChildEventListener() {
            @Override
            public void onChildAdded(DataSnapshot dataSnapshot, String s) {

                ed.setText("");





            }





    }


}

以下是我的Adapter类

public class MessagePopulator extends RecyclerView.Adapter<MessagePopulator.MyViewHolder> {


    private List<Messages> messageList;
    public MessagePopulator(List<Messages> mList) {
        this.messageList = mList;
    }

    public List<Messages> getMessageList() {
        return messageList;
    }

    public void setMessageList(List<Messages> messageList) {
        this.messageList = messageList;
    }


    /*public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View itemView = LayoutInflater.from(parent.getContext()).
                inflate(R.layout.messageslist, parent, false);
        return new MyViewHolder(itemView);
        //return null;
    }*/



    @Override
    public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View itemView = LayoutInflater.from(parent.getContext()).
                inflate(R.layout.messageslist, parent, false);
        return new MyViewHolder(itemView);
        //return null;
    }

    @Override
    public void onBindViewHolder(MyViewHolder holder, int position) {
        //System.out.println("position is "+ position);
        Messages msgs = messageList.get(position);
        //System.out.println("vidhu data "+msgs.getCaseType()+"/"+msgs.getCaseNumber()+"/"+msgs.getCaseYear());
        holder.caseDetail.setText(msgs.getCaseType()+"/"+msgs.getCaseNumber()+"/"+msgs.getCaseYear());
        holder.caseStatus.setText(msgs.getStatus());

    }

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


    public class MyViewHolder extends RecyclerView.ViewHolder {
        public TextView caseDetail, caseStatus;

        public MyViewHolder(View view) {
            super(view);
            caseDetail = (TextView) view.findViewById(R.id.tvCaseDetail);
            caseStatus = (TextView) view.findViewById(R.id.tvStatus);

        }
    }
}

Answer 1

只需使用官方Firebase repository

中的FirebaseRecyclerAdapter即可

以下是官方文档中的示例代码：

FirebaseRecyclerAdapter adapter = new FirebaseRecyclerAdapter<Chat, ChatHolder>(options) {
    @Override
    public ChatHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        // Create a new instance of the ViewHolder, in this case we are using a custom
        // layout called R.layout.message for each item
        View view = LayoutInflater.from(parent.getContext())
                .inflate(R.layout.message, parent, false);

        return new ChatHolder(view);
    }

    @Override
    protected void onBindViewHolder(ChatHolder holder, int position, Chat model) {
        // Bind the Chat object to the ChatHolder
        // ...
    }
};

无法在回收站视图中显示firebase数据

1 个答案: