android – 如何在使用Firebase&ChildEventListener之后保留RecyclerView的方向更改后的位置？

> RecyclerView
> CardView
> Firebase
毕加索

该应用程序从Firebase和Firebase Storage中抓取图像和文本,将它们显示在CardView中,并将OnClickListener设置为每个视图.当用户点击图像时,我通过意图打开一个新的活动.第二个活动显示原始点击的图像,以及更多关于它的信息.

如果用户的手机是VERTICAL,我已经实现了这一切,使用GridLayoutManager 1列,如果用户的手机是HORIZONTAL,则列3列.

我遇到的问题是,似乎无法保存RecyclerView对方向更改的立场.我已经尝试过我可以找到的每一个选项,但没有一个看起来不起作用.我唯一可以想出的结论是,在旋转时,我正在销毁Firebase的ChildEventListener以避免内存泄漏,一旦方向完成,Firebase将重新查询数据库,因为新的ChildEventListener实例.

有没有什么办法可以节省我的RecyclerView的方向改变的立场？我不想要android：configChanges,因为它不会让我改变我的布局,我已经尝试保存为一个包裹,这是不成功的.我确定这是一件容易的东西,我失踪了,但嘿,我很开心.对我的代码的任何帮助或建议非常感谢.谢谢！

以下是我的课程,我只缩写为必需的代码.

主要活动

public class MainActivity extends AppCompatActivity {

private RecyclerAdapter mRecyclerAdapter;
private DatabaseReference mDatabaseReference;
private RecyclerView mRecyclerView;
private Query query;


@Override
protected void onCreate(Bundle savedInstanceStatE) {
    super.onCreate(savedInstanceStatE);

    PreferenceManager.set@R_197_2811@es(this,R.xml.preferences,falsE);
    setContentView(R.layout.activity_main);
    getWindow().setBACkgroundDrawable(new ColorDrawable(Color.TRANSPARENT));

    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);

    final int columns = getresources().getInteger(R.Integer.gallery_columns);

    mDatabaseReference = FirebaseDatabase.geTinstance().getReference();
    query = mDatabaseReference.child("apod").orderByChild("date");

    mRecyclerView = (RecyclerView) findViewById(R.id.recycler_view);
    mRecyclerView.setHasFixedSize(true);
    mRecyclerView.setLayoutManager(new GridLayoutManager(this,columns));


    mRecyclerAdapter = new RecyclerAdapter(this,query);
    mRecyclerView.setAdapter(mRecyclerAdapter);


  }

@Override
public void onDestroy() {
    mRecyclerAdapter.cleanupListener();
  }

}

RecyclerAdapter

public class RecyclerAdapter extends RecyclerView.Adapter<RecyclerAdapter.ApodViewHolder> {

private final Context mContext;
private final ChildEventListener mChildEventListener;
private final Query mDatabaseReference;
private final List<String> apodListIds = new ArrayList<>();
private final List<Apod> apodList = new ArrayList<>();

public RecyclerAdapter(final Context context,Query ref) {
    mContext = context;
    mDatabaseReference = ref;


    ChildEventListener childEventListener = new ChildEventListener() {


        @Override
        public void onChildAdded(DataSnapshot dataSnapshot,String s) {
            int oldListSize = getItemCount();
            Apod apod = dataSnapshot.getValue(Apod.class);

            //Add data and IDs to the list
            apodListIds.add(dataSnapshot.getKey());
            apodList.add(apod);

            //update the RecyclerView
            notifyItemInserted(oldListSize - getItemCount() - 1);
        }

        @Override
        public void onChildChanged(DataSnapshot dataSnapshot,String s) {

        }

        @Override
        public void onChildRemoved(DataSnapshot dataSnapshot) {
            String apodKey = dataSnapshot.getKey();
            int apodIndex = apodListIds.indexOf(apodKey);

            if (apodIndex > -1) {

                // Remove data and IDs from the list
                apodListIds.remove(apodIndeX);
                apodList.remove(apodIndeX);

                // update the RecyclerView
                notifyDataSetChanged();
            }
        }

        @Override
        public void onChildMoved(DataSnapshot dataSnapshot,String s) {

        }

        @Override
        public void onCancelled(DatabaseError databaseError) {

        }

    };
    ref.addChildEventListener(childEventListener);
    mChildEventListener = childEventListener;

 }

   @Override
    public int getItemCount() {
    return apodList.size();
}
    public void cleanupListener() {
    if (mChildEventListener != null) {
        mDatabaseReference.removeEventListener(mChildEventListener);
    }
  }

}