Question

我正在尝试将数据库中的数据读取到recyclerview列表中。

项目数已正确检索，因此我的数据库引用工作正常，但数据为空。

这是我用来检索数据并将其绑定到我的模型类的代码-

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

    getSupportActionBar().hide();
    FirebaseApp.initializeApp(this);

    mButtonSend = findViewById(R.id.button_send);
    mEditTextFileName = findViewById(R.id.comment_field);

    mRecyclerView = findViewById(R.id.recycler_view_too);
    mRecyclerView.setLayoutManager(new LinearLayoutManager(this));
    mcUploads = new ArrayList<>();
    mStorage = FirebaseStorage.getInstance();
    mDatabaseRef = 
FirebaseDatabase.getInstance().getReference("Comments");
    mAdapter = new RecyclerViewAdapterComment(PostActivity.this, 
mcUploads);
    mRecyclerView.setAdapter(mAdapter);

     mDatabaseRef.addValueEventListener(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            for (DataSnapshot postSnapshot : dataSnapshot.getChildren()) {
                Comments upload = postSnapshot.getValue(Comments.class);
                mcUploads.add(upload);

                Log.e("ccmain", "This is my message" + mcUploads);
            }
            mAdapter.notifyDataSetChanged();
        }

        @Override
        public void onCancelled(DatabaseError databaseError) {
            Toast.makeText(PostActivity.this, databaseError.getMessage(), 
 Toast.LENGTH_SHORT).show();
        }
    });


    mButtonSend.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            if (mUploadTask != null && mUploadTask.isInProgress()) {
                Toast.makeText(PostActivity.this, "Comment is being sent", 
Toast.LENGTH_SHORT).show();
            } else {
                uploadComment();
            }
        }
    });
}


private void uploadComment() {
    if (mEditTextFileName == null ) {
        Toast.makeText(this, "Type something", Toast.LENGTH_LONG).show();
    } else {

                Comments upload;

                //call the constructor from the Posts class in "models" package
                upload = new Comments(mEditTextFileName.getText().toString().trim());

                String uploadId = mDatabaseRef.push().getKey();
                mDatabaseRef.child(uploadId).setValue(upload);

            }
        }


}

这是我的RecyclerViewAdapter类-

public class RecyclerViewAdapterComment extends RecyclerView.Adapter<RecyclerViewAdapterComment.ImageViewHolderComment> {

private Context mContext;
private List<Comments> mcUploads;

public RecyclerViewAdapterComment(Context context, List<Comments> uploads) {
    mContext = context;
    mcUploads = uploads;
}

@Override
public ImageViewHolderComment onCreateViewHolder(ViewGroup parent, int viewType) {
    View v = LayoutInflater.from(mContext).inflate(R.layout.comment_single_item, parent, false);
    return new ImageViewHolderComment(v);
}

@Override
public void onBindViewHolder(ImageViewHolderComment holder, int position) {
    Comments uploadCurrent = mcUploads.get(position);
    holder.commentText.setText(uploadCurrent.getComment());
    Picasso.get().load(uploadCurrent.getProfile_p_url()).fit().centerCrop().into(holder.commentPhoto);

//LOGS
Log.e("rcc","::"+mcUploads.get(position));
Log.e("rcc","::"+uploadCurrent.getComment());
Log.e("rcc","::"+uploadCurrent.getProfile_p_url());

}

@Override
public int getItemCount() {
    return mcUploads.size();
}

public class ImageViewHolderComment extends RecyclerView.ViewHolder {

    public TextView commentText;
    public ImageView commentPhoto;

    public ImageViewHolderComment(@NonNull View itemView) {
        super(itemView);

        commentText = itemView.findViewById(R.id.comment_content);
        commentPhoto = itemView.findViewById(R.id.comment_photo);
    }
}
}

在我的bindViewHolder上，mcUploads.get(position)的数据也正确显示，但是

holder.commentText.setText(uploadCurrent.getComment());
Picasso.get().load(uploadCurrent.getProfile_p_url()).fit().centerCrop().into(holder.commentPhoto);

都为空

评论模型类别：

package com.example.atelier.models;

import com.google.firebase.database.Exclude;

public class Comments {

private String comment;
private String profile_p_url;
private String mKey;

public Comments() {
}

public Comments(String comment) {
    this.comment = comment;
}


public String getComment() {
    return comment;
}

public String getProfile_p_url() {
    return profile_p_url;
}


public void setComment(String description) {
    this.comment = comment;
}
public void setProfile_p_url(String image_url) {
    this.profile_p_url = profile_p_url;
}


@Exclude
public String getKey() {
    return mKey;
}

@Exclude
public void setKey(String key) {
    mKey = key;
}

}

数据库结构：（其中一些也有图像，但是我只对文本感到满意，然后我自己就能弄清楚）

{
"Comments" : {
"-LvzF_VRJQ25bTUZK-dt" : {
  "comment" : "woooorrrkk",
  "profile_p_url" : "https://firebasestorage.googleapis.co..."
},
"-LvzRnxOZI6MMTMcg0Nf" : {
  "comment" : "ngsjtsjyskydkysoy",
  "profile_p_url" : "https://firebasestorage.googleapis..."
},
"-LvzYP1jevJYongMxGiJ" : {
  "comment" : "kgsjiiyxkgxkt"
},
"-Lvz_5aM-kIg6qaKPFjv" : {
  "comment" : 
"jajhahahannabahhsbsbbs"
}`

日志返回：

2019-12-13 15:50:17.972 5664-5664/com.example.atelier E/rcc: 
::com.example.atelier.models.Comments@54e5ea1
2019-12-13 15:50:17.972 5664-5664/com.example.atelier E/rcc: ::null
2019-12-13 15:50:17.972 5664-5664/com.example.atelier E/rcc: ::null
2019-12-13 15:50:17.979 5664-5664/com.example.atelier E/rcc: 
::com.example.atelier.models.Comments@c4b4d02
2019-12-13 15:50:17.979 5664-5664/com.example.atelier E/rcc: ::null
2019-12-13 15:50:17.979 5664-5664/com.example.atelier E/rcc: ::null
2019-12-13 15:50:17.984 5664-5664/com.example.atelier E/rcc: 
::com.example.atelier.models.Comments@4be635f
2019-12-13 15:50:17.984 5664-5664/com.example.atelier E/rcc: ::null
2019-12-13 15:50:17.984 5664-5664/com.example.atelier E/rcc: ::null
2019-12-13 15:50:17.989 5664-5664/com.example.atelier E/rcc: 
::com.example.atelier.models.Comments@171bbc8
2019-12-13 15:50:17.989 5664-5664/com.example.atelier E/rcc: ::null
2019-12-13 15:50:17.989 5664-5664/com.example.atelier E/rcc: ::null

Firebase返回空值

0 个答案: