Android 如何按照实施Firebase的时间顺序对回收器视图的元素进行排序？

我试图对我的回收者视图中的元素进行排序，这些照片是上传的，但它们从最旧的到最后的顺序是我发现的最新的，但我不知道如何解决它

我的回收器类是一个片段：

 public class PostFragment extends Fragment {

private View mRootView;
private FirebaseRecyclerAdapter<Post, PostHolder> mPostAdapter;
private RecyclerView mPostRecyclerView;

public PostFragment() {
}

@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
                         Bundle savedInstanceState) {
    // Inflate the layout for this fragment
    mRootView = inflater.inflate(R.layout.fragment_post, container, false);
    FloatingActionButton fab = (FloatingActionButton) mRootView.findViewById(R.id.fabM);
    fab.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            PostCreateDialog dialog = new PostCreateDialog();
            dialog.show(getFragmentManager(), null);
        }
    });
    init();
    return mRootView;
}

private void init() {
    mPostRecyclerView = (RecyclerView) mRootView.findViewById(R.id.recyclerview_post);
    mPostRecyclerView.setLayoutManager(new LinearLayoutManager(getContext()));
    setupAdapter();
    mPostRecyclerView.setAdapter(mPostAdapter);

}

private void setupAdapter() {
    mPostAdapter = new FirebaseRecyclerAdapter<Post, PostHolder>(
            Post.class,
            R.layout.row_post,
            PostHolder.class,
            FirebaseUtils.getPostRef()
    ) {
        @Override
        protected void populateViewHolder(final PostHolder viewHolder, final Post model, int position) {
            viewHolder.setNumComments(String.valueOf(model.getNumComments()));
            viewHolder.setNumLikes(String.valueOf(model.getNumLikes()));
            viewHolder.setTime(DateUtils.getRelativeTimeSpanString(model.getTimeCreated()));
            viewHolder.postOwnerUsernameTextView.setText(model.getUsername());
            if(viewHolder.postOwnerUsernameTextView == null){
                viewHolder.postOwnerUsernameTextView.setText("Anonymous");
            }
            viewHolder.setPostText(model.getPostText());



                final StorageReference storageReference = FirebaseStorage.getInstance()
                        .getReference(model.getPostImageUrl());

            Glide.with(getActivity())
                    .using(new FirebaseImageLoader())
                    .load(storageReference).crossFade().fitCenter().into(viewHolder.postDisplayImageView);






            viewHolder.postLikeLayout.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    onLikeClick(model.getPostId());
                }
            });

            viewHolder.postCommentLayout.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    Intent intent = new Intent(getContext(), CommentActivity.class);
                    intent.putExtra(Constants.EXTRA_POST, model);
                    startActivity(intent);
                }
            });





        }
    };
}




private void onLikeClick(final String postId) {
    FirebaseUtils.getPostLikedRef(postId)
            .addListenerForSingleValueEvent(new ValueEventListener() {
                @Override
                public void onDataChange(DataSnapshot dataSnapshot) {
                    if (dataSnapshot.getValue() != null) {
                        //user liked
                        FirebaseUtils.getPostRef()
                                .child(postId)
                                .child("numLikes")
                                .runTransaction(new Transaction.Handler() {
                                    @Override
                                    public Transaction.Result doTransaction(MutableData mutableData) {
                                        long num = mutableData.getValue(Long.class);
                                        mutableData.setValue(num - 1);
                                        return Transaction.success(mutableData);
                                    }

                                    @Override
                                    public void onComplete(DatabaseError databaseError, boolean b, DataSnapshot dataSnapshot) {
                                        FirebaseUtils.getPostLikedRef(postId)
                                                .setValue(null);
                                    }
                                });
                    } else {
                        FirebaseUtils.getPostRef()
                                .child(postId)
                                .child("numLikes")
                                .runTransaction(new Transaction.Handler() {
                                    @Override
                                    public Transaction.Result doTransaction(MutableData mutableData) {
                                        long num = mutableData.getValue(Long.class);
                                        mutableData.setValue(num + 1);
                                        return Transaction.success(mutableData);
                                    }

                                    @Override
                                    public void onComplete(DatabaseError databaseError, boolean b, DataSnapshot dataSnapshot) {
                                        FirebaseUtils.getPostLikedRef(postId)
                                                .setValue(true);
                                    }
                                });
                    }
                }

                @Override
                public void onCancelled(DatabaseError databaseError) {

                }
            });
}

public static class PostHolder extends RecyclerView.ViewHolder {
    TextView postOwnerUsernameTextView;
    TextView postTimeCreatedTextView;

    ImageView postDisplayImageView;
    TextView postTextTextView;

    LinearLayout postLikeLayout;
    TextView postNumLikesTextView;

    LinearLayout postCommentLayout;
    TextView postNumCommentsTextView;



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

        postOwnerUsernameTextView = (TextView) itemView.findViewById(R.id.tv_post_username);
        postTimeCreatedTextView = (TextView) itemView.findViewById(R.id.tv_time);
        postDisplayImageView = (ImageView) itemView.findViewById(R.id.iv_post_display);
        postLikeLayout = (LinearLayout) itemView.findViewById(R.id.like_layout);
        postCommentLayout = (LinearLayout) itemView.findViewById(R.id.comment_layout);
        postNumLikesTextView = (TextView) itemView.findViewById(R.id.tv_likes);
        postNumCommentsTextView = (TextView) itemView.findViewById(R.id.tv_comments);
        postTextTextView = (TextView) itemView.findViewById(R.id.tv_post_text);


    }

    public void setUsername(String username) {
        postOwnerUsernameTextView.setText(username);
    }

    public void setTime(CharSequence time) {
        postTimeCreatedTextView.setText(time);
    }

    public void setNumLikes(String numLikes) {
        postNumLikesTextView.setText(numLikes);
    }

    public void setNumComments(String numComments) {
        postNumCommentsTextView.setText(numComments);
    }

    public void setPostText(String text) {
        postTextTextView.setText(text);
    }


}

}

public类PostFragment扩展了片段{
私人视图mRootView；
私人FirebaseRecyclerAdapter MPOStatadapter；
私人回收视图MPostrecycleView；
公共PostFragment（）{
}
@凌驾
创建视图上的公共视图（布局、充气机、视图组容器、，
Bundle savedInstanceState）{
//为该碎片膨胀布局
mRootView=充气机。充气（R.layout.fragment_post，容器，假）；
FloatingActionButton fab=（FloatingActionButton）mRootView.findViewById（R.id.fabM）；
fab.setOnClickListener（新视图.OnClickListener（）{
@凌驾
公共void onClick（视图v）{
PostCreateDialog=新建PostCreateDialog（）；
show（getFragmentManager（），null）；
}
});
init（）；
返回mRootView；
}
私有void init（）{
mPostRecyclerView=（RecyclerView）mRootView.findViewById（R.id.RecyclerView\u post）；
setLayoutManager（新的LinearLayoutManager（getContext（））；
setupAdapter（）；
mPostRecyclerView.setAdapter（mpostatadapter）；
}
私有void setupAdapter（）{
MPOStatadapter=新的FirebaseRecyclerAdapter(
课后，
R.layout.row_柱，
邮递员，
FirebaseUtils.getPostRef（）
) {
@凌驾
受保护的void populateViewHolder（最终PostHolder viewHolder，最终Post模型，内部位置）{
viewHolder.setNumComments（String.valueOf（model.getNumComments（））；
viewHolder.setNumLikes（String.valueOf（model.getNumLikes（））；
setTime（DateUtils.getRelativeTimeSpanString（model.getTimeCreated（））；
viewHolder.postOwnerUsernameTextView.setText（model.getUsername（））；
if（viewHolder.postOwnerUsernameTextView==null）{
viewHolder.postOwnerUsernameTextView.setText（“匿名”）；
}
setPostText（model.getPostText（））；
final-StorageReference-StorageReference=FirebaseStorage.getInstance（）
.getReference（model.getPostImageUrl（））；
Glide.with（getActivity（））
.使用（新的FireBaseMageLoader（））
.load（storageReference）.crossFade（）.fitCenter（）加载到（viewHolder.postDisplayImageView）中；
viewHolder.postLikeLayout.setOnClickListener（新的View.OnClickListener（）{
@凌驾
公共void onClick（视图v）{
onlikelick（model.getPostId（））；
}
});
viewHolder.postCommentLayout.setOnClickListener（新视图.OnClickListener（）{
@凌驾
公共void onClick（视图v）{
Intent Intent=新的Intent（getContext（），CommentActivity.class）；
intent.putExtra（Constants.EXTRA_POST，model）；
星触觉（意向）；
}
});
}
};
}
私有void onlikelick（最后一个字符串posted）{
FirebaseUtils.getPostLikedRef（postId）
.addListenerForSingleValueEvent（新的ValueEventListener（）{
@凌驾
公共void onDataChange（DataSnapshot DataSnapshot）{
if（dataSnapshot.getValue（）！=null）{
//用户喜欢
FirebaseUtils.getPostRef（）
.儿童（职位）
.儿童（“核弹”）
.runTransaction（新事务处理程序（）{
@凌驾
公共事务.Result doTransaction（MutableData MutableData）{
long num=mutableData.getValue（long.class）；
设置值（num-1）；
返回事务。成功（可变数据）；
}
@凌驾
public void onComplete（DatabaseError DatabaseError、布尔b、DataSnapshot DataSnapshot）{
FirebaseUtils.getPostLikedRef（postId）
.setValue（空）；
}
});
}否则{
FirebaseUtils.getPostRef（）
.儿童（职位）
.儿童（“核弹”）
.runTransaction（新事务处理程序（）{
@凌驾
公共事务.Result doTransaction（MutableData MutableData）{
long num=mutableData.getValue（long.class）；
mutableData.setValue（num+1）；
返回事务。成功（可变数据）；
}
@凌驾
public void onComplete（DatabaseError DatabaseError、布尔b、DataSnapshot DataSnapshot）{
FirebaseUtils.getPostLikedRef（postId）
.setValue（真）；
}
});
}
}
@凌驾
已取消的公共void（DatabaseError DatabaseError）{
}
});
}
公共静态类PostHolder扩展了RecyclerView.ViewHolder{
    public class PostCreateDialog extends DialogFragment implements          View.OnClickListener {
private static final int RC_PHOTO_PICKER = 1;
private View mRootView;
private Post mPost;

private ProgressDialog mProgressDialog;
private Uri mSelectedImageUri;
private ImageView mPostDisplay;
@NonNull
@Override
public Dialog onCreateDialog(Bundle savedInstanceState) {
    AlertDialog.Builder builder = new AlertDialog.Builder(getActivity());
    mPost = new Post();
    mProgressDialog = new ProgressDialog(getContext());

    mRootView = getActivity().getLayoutInflater().inflate(R.layout.post_create_dialog, null);
    mPostDisplay = (ImageView) mRootView.findViewById(R.id.post_dialog_display);
    mRootView.findViewById(R.id.post_dialog_select_imageview).setOnClickListener(this);
    mRootView.findViewById(R.id.post_dialog_send_imageview).setOnClickListener(this);
    builder.setView(mRootView);
    return builder.create();
}

@Override
public void onClick(View v) {
    switch (v.getId()) {
        case R.id.post_dialog_send_imageview:
            sendPost();
            break;
        case R.id.post_dialog_select_imageview:
            selectImage();
            break;
    }
}

private void selectImage() {
    Intent intent = new Intent(Intent.ACTION_GET_CONTENT);
    intent.setType("image/jpeg");
    intent.putExtra(Intent.EXTRA_LOCAL_ONLY, true);
    startActivityForResult(Intent.createChooser(intent, "Complete action using"), RC_PHOTO_PICKER);
}

private void sendPost() {
    mProgressDialog.setMessage("Sending post...");
    mProgressDialog.setCancelable(false);
    mProgressDialog.setIndeterminate(true);
    mProgressDialog.show();

    FirebaseUtils.getUserRef(FirebaseUtils.getCurrentUser().getEmail().replace(".", ","))
            .addListenerForSingleValueEvent(new ValueEventListener() {
                @Override
                public void onDataChange(DataSnapshot dataSnapshot) {
                    User user = dataSnapshot.getValue(User.class);
                    final String postUid = FirebaseUtils.getUid();
                    TextView postDialogTextView = (TextView) mRootView.findViewById(R.id.post_dialog_edittext);
                    String text = postDialogTextView.getText().toString();
                    RegisterActivity r = new RegisterActivity();

                    mPost.setNumComments(0);
                    mPost.setNumLikes(0);
                    mPost.setTimeCreated(System.currentTimeMillis());
                    mPost.setPostId(postUid);
                    mPost.setPostText(text);




                    if (mSelectedImageUri != null) {
                        FirebaseUtils.getImagesSRef()
                                .child(mSelectedImageUri.getLastPathSegment())
                                .putFile(mSelectedImageUri)
                                .addOnSuccessListener(getActivity(),
                                        new OnSuccessListener<UploadTask.TaskSnapshot>() {
                                            @Override
                                            public void onSuccess(UploadTask.TaskSnapshot taskSnapshot) {
                                                String url = Constants.POST_IMAGES + "/" + mSelectedImageUri.getLastPathSegment();
                                                //String downloadUrl = taskSnapshot.getDownloadUrl().toString();
                                                mPost.setPostImageUrl(url);
                                                addToMyPostList(postUid);
                                            }


                                        });
                    } else {
                        Toast.makeText(getContext(), "No puedes postear sin imagen", Toast.LENGTH_LONG).show();
                        mProgressDialog.dismiss();
                    }
                }

                @Override
                public void onCancelled(DatabaseError databaseError) {
                    mProgressDialog.dismiss();
                }
            });
}

private void addToMyPostList(final String postUid) {
    FirebaseUtils.getPostRef().child(postUid)
            .setValue(mPost);
    FirebaseUtils.getMyPostRef().child(postUid).setValue(true)
            .addOnCompleteListener(getActivity(), new OnCompleteListener<Void>() {
                @Override
                public void onComplete(@NonNull Task<Void> task) {
                    mProgressDialog.dismiss();
                    dismiss();
                }
            });

    FirebaseUtils.addToMyRecord(Constants.POSTS_KEY, postUid);
}

@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
    super.onActivityResult(requestCode, resultCode, data);
    if (requestCode == RC_PHOTO_PICKER) {
        if (resultCode == RESULT_OK) {
            mSelectedImageUri = data.getData();
            mPostDisplay.setImageURI(mSelectedImageUri);
        }
    }
}
}

   public static DatabaseReference getUserRef(String email) {
    return FirebaseDatabase.getInstance()
            .getReference(Constants.USERS_KEYS)
            .child(email);
}
public static FirebaseUser getCurrentUser() {
    return FirebaseAuth.getInstance().getCurrentUser();
}






// POST REFERENCE
public static DatabaseReference getPostRef() {
    return FirebaseDatabase.getInstance()
            .getReference(Constants.POSTS_KEY);
}
public static Query getPostQuery() {
    return getPostRef().orderByChild(Constants.TIME_CREATED_KEY);
}
public static DatabaseReference getMyPostRef() {
    return FirebaseDatabase.getInstance().getReference(Constants.MY_POSTS)
            .child(getCurrentUser().getEmail().replace(".", ","));
}





// POST LIKED REFERENCE
public static DatabaseReference getPostLikedRef() {
    return FirebaseDatabase.getInstance()
            .getReference(Constants.POSTS_LIKED_KEY);
}
public static DatabaseReference getPostLikedRef(String postId) {
    return getPostLikedRef().child(getCurrentUser().getEmail()
            .replace(".", ","))
            .child(postId);
}








// USER ID
public static String getUid() {
    String path = FirebaseDatabase.getInstance().getReference().push().toString();
    return path.substring(path.lastIndexOf("/") + 1);
}







// POST IMAGE REFERENCE
public static StorageReference getImagesSRef() {
    return FirebaseStorage.getInstance().getReference(Constants.POST_IMAGES);
}








// COMMENT REFERENCE
public static DatabaseReference getCommentRef(String postId) {
    return FirebaseDatabase.getInstance().getReference(Constants.COMMENTS_KEY)
            .child(postId);
}







// RECORD

public static DatabaseReference getMyRecordRef() {
    return FirebaseDatabase.getInstance().getReference(Constants.USER_RECORD)
            .child(getCurrentUser().getEmail().replace(".", ","));
}



public static void addToMyRecord(String node,final String id) {
    FirebaseUtils.getMyRecordRef().child(node).runTransaction(new Transaction.Handler() {
        @Override
        public Transaction.Result doTransaction(MutableData mutableData) {
            ArrayList<String> myPostCollection;
            if (mutableData.getValue() == null) {
                myPostCollection = new ArrayList<>(1);
                myPostCollection.add(id);
                mutableData.setValue(myPostCollection);
            } else {
                myPostCollection = (ArrayList<String>) mutableData.getValue();
                myPostCollection.add(id);
                mutableData.setValue(myPostCollection);
            }
            return Transaction.success(mutableData);
        }

        @Override
        public void onComplete(DatabaseError databaseError, boolean b, DataSnapshot dataSnapshot) {

        }
    });
}
}

private void setupAdapter() {
    mPostAdapter = new FirebaseRecyclerAdapter<Post, PostHolder>(
        Post.class,
        R.layout.row_post,
        PostHolder.class,
       FirebaseDatabase.getInstance().getReference(Constants.POSTS_KEY).orderByChild("TimeCreated")
    ) 
}