如何在TabLayout的片段中加载Firebase中的数据？

Question

非常感谢您阅读我的代码。我已经创建了TabLayout并为其分配了View Pager。我能够滑动以查看不同的碎片。我有三个片段，＆＃34;所有＆＃34;，＆＃34;科学＆＃34;和＆＃34;世界＆＃34;。

重要的是，我可以根据需要在回收站视图中加载数据，并且一切都可以正常使用MainActivity.java。但是，我为AllFragment尝试了同样的事情，但它没有用。有人可以帮我这个吗？谢谢！

这是我的 AllFragment.java

public class AllFragment extends Fragment
{
    /*UI*/
    private RecyclerView mPostList;

    /*Firebase*/
    private DatabaseReference mDatabasePost;
    private DatabaseReference mDatabaseUser;
    private Firebase firebaseRef;
    private FirebaseAuth mAuth;

    public AllFragment()
    {

    }

    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
    {
        View view = inflater.inflate(R.layout.fragment_all, container, false);

        /*UI*/
        mPostList =     (RecyclerView)view.findViewById(R.id.fragment_all_recycler_view);

        /*Firebase*/
        Firebase.setAndroidContext(getActivity());
        firebaseRef = new Firebase(FIREBASE_URL);
        mAuth = FirebaseAuth.getInstance();
        mDatabaseUser = FirebaseDatabase.getInstance().getReference().child("User");
        mDatabaseUser.keepSynced(true);
        mDatabasePost = FirebaseDatabase.getInstance().getReference().child("Post");
        mDatabasePost.keepSynced(true);

        /*Others*/
        LinearLayoutManager layoutManager = new LinearLayoutManager(getActivity());
        layoutManager.setReverseLayout(true);
        layoutManager.setStackFromEnd(true);
        mPostList.setHasFixedSize(true);
        mPostList.setLayoutManager(layoutManager);

        FirebaseRecyclerAdapter<Post, PostViewHolder> firebaseRecyclerAdapter = new FirebaseRecyclerAdapter<Post, PostViewHolder>(
                Post.class,
                R.layout.post_row,
                PostViewHolder.class,
                mDatabasePost
        )
        {
            @Override
            protected void populateViewHolder(PostViewHolder viewHolder, Post model, int position)
            {
                final String post_key = getRef(position).getKey();

                viewHolder.setDebate(model.getDebate());
                viewHolder.setDisplayName("by " + model.getDisplayName());

                final String room_name = model.getDebate();

                viewHolder.mView.setOnClickListener(new View.OnClickListener()
                {
                    @Override
                    public void onClick(View v)
                    {
                        Intent i = new Intent(getActivity(), SingleDebateActivity.class);

                        i.putExtra("room_name", room_name);
                        i.putExtra("post_key", post_key);

                        startActivity(i);
                    }
                });
            }
        };

        mPostList.setAdapter(firebaseRecyclerAdapter);

        return view;
    }

    public static class PostViewHolder extends RecyclerView.ViewHolder
    {
        View mView;

        FirebaseAuth mAuth;

        public PostViewHolder(View itemView)
        {
            super(itemView);

            mView = itemView;

            mAuth = FirebaseAuth.getInstance();
        }

        public void setDebate(String debate)
        {
            TextView postDebate = (TextView)mView.findViewById(R.id.post_row_display_debate);
            postDebate.setText(debate);
        }

        public void setDisplayName(String displayName)
        {
            TextView postDisplayName = (TextView)mView.findViewById(R.id.post_row_display_displayName);
            postDisplayName.setText(displayName);
        }
    }
}

这是我的 fragment_all.xml

<FrameLayout    
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <LinearLayout
        android:id="@+id/fragment_all_linear_layout"
        android:orientation="vertical"
        android:layout_width="match_parent"
        android:layout_height="match_parent">

        <android.support.v7.widget.RecyclerView
            android:id="@+id/fragment_all_recycler_view"
            android:layout_width="match_parent"
            android:layout_height="0dp"
            android:scrollbars="vertical">

        </android.support.v7.widget.RecyclerView>
    </LinearLayout>
</FrameLayout>

这是我的 ViewPagerAdapter.java

public class ViewPagerAdapter extends FragmentPagerAdapter
{
    ArrayList<Fragment> fragments = new ArrayList<>();
    ArrayList<String> tabTitles = new ArrayList<>();

    public void addFragments(Fragment fragments, String titles)
    {
        this.fragments.add(fragments);
        this.tabTitles.add(titles);
    }
    public ViewPagerAdapter(FragmentManager fm)
    {
        super(fm);
    }

    @Override
    public Fragment getItem(int position)
    {
        return fragments.get(position);
    }

    @Override
    public int getCount()
    {
        return fragments.size();
    }

    @Override
    public CharSequence getPageTitle(int position)
    {
        return tabTitles.get(position);
    }
}