从Firebase的回收器视图中检索数据后，片段中的浮动操作按钮不可单击

Question

我正在尝试制作一个问题应用程序，让学生可以向老师提问。在问题片段中，我使用浮动操作按钮添加问题。它可以单击，然后转到添加页面的问题，但是当我将检索到的数据从Firebase的片段添加到Recycler-view时，就不再可以单击了，请有人可以帮我。

    package com.example.dell.step;


import android.content.Intent;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.view.ViewPager;
import android.support.v7.widget.LinearLayoutManager;
import android.support.v7.widget.RecyclerView;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Toast;

import com.getbase.floatingactionbutton.FloatingActionButton;
import com.google.firebase.firestore.DocumentChange;
import com.google.firebase.firestore.EventListener;
import com.google.firebase.firestore.FirebaseFirestore;
import com.google.firebase.firestore.FirebaseFirestoreException;
import com.google.firebase.firestore.QuerySnapshot;

import java.util.ArrayList;
import java.util.List;


/**
 * A simple {@link Fragment} subclass.
 */
public class QuestionsFragment extends Fragment {

    private RecyclerView question_list_view;
    private List<QuestionPost> question_list;


    private FirebaseFirestore firebaseFirestore;
    private QuestionRecyclerAdapter questionRecyclerAdapter;




    public QuestionsFragment() {
        // Required empty public constructor
    }

    FloatingActionButton fab;


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {


        //Here we create floating action button
        View view =  inflater.inflate(R.layout.fragment_questions, container, false);

        question_list_view = view.findViewById(R.id.question_list_view);

        question_list = new ArrayList<>();

        firebaseFirestore = FirebaseFirestore.getInstance();

        questionRecyclerAdapter = new QuestionRecyclerAdapter(question_list);
        question_list_view.setLayoutManager(new LinearLayoutManager(getActivity()));

        question_list_view.setAdapter(questionRecyclerAdapter);
        question_list_view.setHasFixedSize(true);



        firebaseFirestore.collection("questions").addSnapshotListener(new EventListener<QuerySnapshot>() {
            @Override
            public void onEvent(QuerySnapshot documentSnapshots, FirebaseFirestoreException e) {

                for (DocumentChange doc: documentSnapshots.getDocumentChanges()) {

                    if(doc.getType() == DocumentChange.Type.ADDED){


                        QuestionPost questionPost = doc.getDocument().toObject(QuestionPost.class);
                        question_list.add(questionPost);

                        questionRecyclerAdapter.notifyDataSetChanged();
                    }


                }

            }
        });



        fab = view.findViewById(R.id.Ask_question);
        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Toast.makeText(getActivity(),"Working", Toast.LENGTH_LONG).show();
                Intent fileIntent = new Intent(getActivity(), Add_question.class);
                startActivity(fileIntent);



            }
        });




        // Inflate the layout for this fragment
        return view;
    }

}



questionfragment.xml

    <RelativeLayout 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.dell.step.QuestionsFragment">

    <!-- TODO: Update blank fragment layout -->

    <com.getbase.floatingactionbutton.FloatingActionsMenu
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_alignParentBottom="true"
        android:layout_alignParentEnd="true"
        app:fab_addButtonColorNormal="@color/colorPrimaryDark"

        app:fab_addButtonColorPressed="@color/colorPrimary"
        app:fab_labelStyle="@style/floatingBtn_style">


        <com.getbase.floatingactionbutton.FloatingActionButton
            android:id="@+id/Ask_question"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            app:fab_colorNormal="@color/colorPrimaryDark"
            app:fab_colorPressed="@color/colorPrimary"
            app:fab_icon="@mipmap/ic_launcher_question"
            app:fab_size="mini"
            app:fab_title="Ask Question"


            />



    </com.getbase.floatingactionbutton.FloatingActionsMenu>

    <android.support.v7.widget.RecyclerView
        android:id="@+id/question_list_view"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:layout_alignParentStart="true"
        android:layout_alignParentTop="true" />


</RelativeLayout>