android - 使用 firebase 获取一些空值，其他值正常

Question

所以我正在使用 Firebase 数据库发布和检索一些数据。

发布数据工作正常，这是我的帖子树的样子:

Tree

这是我的发帖方式(效果很好)

public void post_status(){
    String full_song = song;
    final String song_name = full_song.split("//")[0];
    final String song_Artist = full_song.split("//")[1];

    final DatabaseReference db_post = DB_NewPost.push();
    if (song_name != null && song_Artist !=null && user_name != null && profile_image != null) {
        final ProgressDialog progressDialog = new ProgressDialog(MainActivity.this);
        progressDialog.setTitle("Posting...");
        progressDialog.show();
        DB_NewPost.addValueEventListener(new ValueEventListener() {
            @Override
            public void onDataChange(DataSnapshot dataSnapshot) {

                db_post.child("artist").setValue(song_Artist);
                db_post.child("song_name").setValue(song_name);
                db_post.child("profile_image").setValue(profile_image);
                db_post.child("user_name").setValue(user_name);
                db_post.child("user_comment").setValue("Test Comment");
                db_post.child("user_ID").setValue(user.getUid()).addOnCompleteListener(new OnCompleteListener<Void>() {
                    @Override
                    public void onComplete(@NonNull Task<Void> task) {
                        progressDialog.dismiss();
                    }
                });

            }

            @Override
            public void onCancelled(DatabaseError databaseError) {
                progressDialog.dismiss();
                CafeBar.builder(MainActivity.this)
                        .duration(CafeBar.Duration.MEDIUM)
                        .content("Post " + databaseError.getMessage())
                        .maxLines(4)
                        .theme(CafeBarTheme.Custom(Color.parseColor("#E65100")))
                        .show();
            }
        });
    }
    else {
        CafeBar.builder(MainActivity.this)
                .duration(CafeBar.Duration.MEDIUM)
                .content("Post canceled, make sure all the values are set")
                .maxLines(4)
                .theme(CafeBarTheme.Custom(Color.parseColor("#E65100")))
                .show();
    }
}

这是我的 RecylcerView 相关代码:

@Override
public void onStart() {
    super.onStart();
    Query query = DB_NewPost.limitToLast(10);
    FirebaseRecyclerOptions<user_post> options =
            new FirebaseRecyclerOptions.Builder<user_post>()
                    .setQuery(query, user_post.class)
                    .build();
    FBRA = new FirebaseRecyclerAdapter<user_post, postViewHolder>(options) {
        @Override
        public postViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {

            View view = LayoutInflater.from(parent.getContext())
                    .inflate(R.layout.post_layout, parent, false);

            return new postViewHolder(view);
        }

        @Override
        protected void onBindViewHolder(@NonNull postViewHolder holder, int position, @NonNull user_post model) {

            holder.setUserName(model.getUsername());
            holder.setComment(model.getUser_comment());
            holder.setSongArtist("by: " + model.getSong_artist());
            holder.setSongName(model.getSong_name());
            holder.setPicture(getApplicationContext(), model.getImage());
            Log.e("UserName", "" + model.getUsername());
            Log.e("Comment", "" +model.getUser_comment());
            Log.e("Artist", "" +model.getSong_artist());
            Log.e("SongName", "" +model.getSong_name());
            Log.e("Picture", "" +model.getImage());

        }
    };
    mSongPost.setAdapter(FBRA);
    FBRA.startListening();

}

public static class postViewHolder extends RecyclerView.ViewHolder{

    View mView;
    public postViewHolder(View itemView) {
        super(itemView);
        mView = itemView;
    }

    public void setSongName(String songName){
        TextView song_name = mView.findViewById(R.id.song_name);
        song_name.setText(songName);
    }

    public void setSongArtist(String Artist){
        TextView song_artist = mView.findViewById(R.id.song_artist);
        song_artist.setText(Artist);
    }

    public void setUserName(String userName){
        TextView user_name = mView.findViewById(R.id.user_name);
        user_name.setText(userName);
    }

    public void setComment(String comment){
        TextView user_comment = mView.findViewById(R.id.user_comment_status);
        user_comment.setText(comment);
    }

    public void setPicture(Context ctx,String image){
        CircleImageView profile = mView.findViewById(R.id.photo_view);
       RequestOptions options = new RequestOptions();
        options.centerCrop()
                .diskCacheStrategy(DiskCacheStrategy.ALL)
                .fitCenter()
                .circleCrop();
        Glide.with(ctx)
                .load(image)
                .apply(options)
                .into(profile);
    }

}

这就是我面临的问题，我得到的是 SongName 的字符串值和评论(即使它是固定的)，但其他所有内容都是 NULL 值。我几乎尝试了所有方法，搜索了很多论坛和以前关于分离数据的问题等等……我找不到任何解决方案。有人愿意帮我解决这个问题吗？

这是我的日志:

01-30 16:29:52.736 25015-25015/xerxes.music_feed E/UserName: null 01-30 16:29:52.737 25015-25015/xerxes.music_feed E/Comment: Test Comment 01-30 16:29:52.737 25015-25015/xerxes.music_feed E/Artist: null 01-30 16:29:52.737 25015-25015/xerxes.music_feed E/SongName: The One Hundred - Monster 01-30 16:29:52.737 25015-25015/xerxes.music_feed E/Picture: null

编辑:我也在我的日志中注意到了这一点，尽管我有这些变量的 setter 和 getter。

01-30 16:29:52.734 25015-25015/xerxes.music_feed W/ClassMapper: No setter/field for profile_image found on class xerxes.music_feed.user_post 01-30 16:29:52.734 25015-25015/xerxes.music_feed W/ClassMapper: No setter/field for artist found on class xerxes.music_feed.user_post 01-30 16:29:52.734 25015-25015/xerxes.music_feed W/ClassMapper: No setter/field for user_ID found on class xerxes.music_feed.user_post 01-30 16:29:52.734 25015-25015/xerxes.music_feed W/ClassMapper: No setter/field for user_name found on class xerxes.music_feed.user_post

编辑 2:添加了 Setters/Getters 类

public class user_post {
private String username;
private String song_name;
private String song_artist;
private String user_comment;
private String image;

public user_post(){

}

public user_post(String username, String song_name, String song_artist, String user_comment,String p_image){
    this.username = username;
    this.song_name = song_name;
    this.song_artist = song_artist;
    this.user_comment = user_comment;
    this.image = p_image;
}

public String getUsername() {
    return username;
}

public void setUsername(String username) {
    this.username = username;
}

public String getSong_name() {
    return song_name;
}

public void setSong_name(String song_name) {
    this.song_name = song_name;
}

public String getSong_artist() {
    return song_artist;
}

public void setSong_artist(String song_artist) {
    this.song_artist = song_artist;
}

public String getUser_comment() {
    return user_comment;
}

public void setUser_comment(String user_comment) {
    this.user_comment = user_comment;
}

public String getImage() {
    return image;
}

public void setUserImage(String image) {
    this.image = image;
}

Answer 1

在你的 POJO 中重构这一行

private String username;

为此

private String user_name;

向可能遇到同样问题的人解释

当你用所有的 setters 和 getters 做你的 POJO 类时，所有的 Strings 或 ints ， longs 等 应该 匹配与你的数据库结构相同的名称，并检查数据库中的数据是否有 "" ，例如 phone_number:"359182" ，如果你的数据库就像那样是因为您需要在您的 POJO String phone_number 和 NOT long 或 int phone_number 中声明...如果在您的数据库中 phone_number 是 phone_number: 3049512 没有 "" 这意味着该值是 int ， double 或长

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