无法在Firebase回收器视图中显示数据

我遵循了几个不同的文档来整理我的第一个Firebase回收器视图:

主要有两个方面:

Here 和 here .

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


        RecyclerView mRecyclerView;
        mRecyclerView = (RecyclerView) findViewById(R.id.recyclerView);
        mRecyclerView.setHasFixedSize(true);
        mRecyclerView.setLayoutManager(new LinearLayoutManager(this));

        Query query = myMessagesRef.child(RoomID)
                .orderByKey()
                .limitToLast(50);

        FirebaseRecyclerOptions<Message> options =
                    new FirebaseRecyclerOptions.Builder<Message>()
                            .setQuery(query, Message.class)
                            .build();

        FirebaseRecyclerAdapter adapter = new FirebaseRecyclerAdapter<Message, 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
                final View view = LayoutInflater.from(parent.getContext())
                        .inflate(R.layout.recycler_item, parent, false);

                return new ChatHolder(view);
            }

            @Override
            protected void onBindViewHolder(ChatHolder holder, int position, Message model) {
                //super.onBindViewHolder(holder, position);
                Log.w(TAG, "Some Info on messages 2 " + model.MessageText);
                holder.bindChat(model);

            }



        };
        mRecyclerView.setAdapter(adapter);

    }

这是我的取景夹:

static class ChatHolder extends RecyclerView.ViewHolder{
    TextView mtext;
    //Context mContext;


    public ChatHolder(View v) {
        super(v);
        mtext = (TextView) v.findViewById(com.example.administrationuser.piclo.R.id.textView13);
    }

    public void bindChat(Message mess){
        mtext.setText(mess.MessageText);
    }


}

这是我传递给Firebase和适配器的消息对象(我输入的数据与Firebase同步,没有问题,我对Firebase的查询以正确的格式获取数据):

public static class Message {

    public String UserID;
    public String UserName;
    public String MessageText;

    public Message() {}  // Needed for Firebase

    public Message(String UserID, String UserName, String MessageText) {
        this.UserID = UserID;
        this.UserName = UserName;
        this.MessageText = MessageText;
    }
}

这是我的活动布局XML(名称:Activity\u message\u details.XML): (请注意底部附近的回收器视图):

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.example.administrationuser.piclo.MessageDetails">

    <LinearLayout
        android:layout_width="395dp"
        android:layout_height="643dp"
        app:layout_behavior="@string/appbar_scrolling_view_behavior"
        android:orientation="vertical"
        tools:layout_editor_absoluteY="8dp"
        tools:layout_editor_absoluteX="8dp">

        <RelativeLayout
            android:layout_width="match_parent"
            android:layout_height="150dp"
            app:layout_behavior="@string/appbar_scrolling_view_behavior">

            <EditText
                android:id="@+id/editText3"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:ems="10"
                android:inputType="textPersonName"
                android:text="Name"
                app:layout_behavior="@string/appbar_scrolling_view_behavior" />

            <Button
                android:id="@+id/button9"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_alignParentRight="true"
                android:text="Button"
                app:layout_behavior="@string/appbar_scrolling_view_behavior"
                android:onClick="onClick"/>
        </RelativeLayout>

        <android.support.v7.widget.RecyclerView
            android:id="@+id/recyclerView"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:drawSelectorOnTop="false"
            />



    </LinearLayout>




</android.support.constraint.ConstraintLayout>

最后,这里是我的视图布局XML(名称:recycler\u item.XML):

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout  xmlns:android="http://schemas.android.com/apk/res/android"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="match_parent">

    <TextView
        android:id="@+id/textView13"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="TextView" />

</FrameLayout >