我已经从 ListView 切换到 RecyclerView，并且我使用来自 Firebase 的数据动态添加 RecyclerView 项目。但是，我无法成功生成 RecyclerView。

目前，屏幕是空白的，并且没有 CardView 项目被添加到 View 中。我假设我的 RecyclerView 适配器有问题。

我的监听器，我在此处添加到 mCommentArrayList，然后从我的 RecyclerView 适配器中提取此数据:

  mUpdateRef.addListenerForSingleValueEvent(new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            setImage(dataSnapshot);
            setQuestion(dataSnapshot);
            createInitialCommentIDArray(dataSnapshot);
            mNumberOfCommentsAtPoll = (int) dataSnapshot.child(COMMENTS_LABEL).getChildrenCount();
            for (int i = 0; i < mNumberOfCommentsAtPoll; i++) {
                String commentID = (String) dataSnapshot.child(COMMENTS_LABEL).child(mCommentIDArrayList.get(i)).child("COMMENT").getValue();
                Log.v("COMMENT_ID", "The comment ID is " + commentID);
                String userID = (String) dataSnapshot.child(COMMENTS_LABEL).child(mCommentIDArrayList.get(i)).child("USER_ID").getValue();
                Log.v("USER_ID", "The user ID is " + userID);
                mCommentArrayList.add(0 , new Comments(mUserAvatar, userID, commentID));
                mCommentAdapter.notifyDataSetChanged();
            }

        }

        @Override
        public void onCancelled(FirebaseError firebaseError) {

        }
    });

这是我的 RecyclerView 适配器:

public class MyAdapter extends RecyclerView.Adapter<MyAdapter.ViewHolder> {

    // Provide a reference to the views for each data item
    // Complex data items may need more than one view per item, and
    // you provide access to all the views for a data item in a view holder
    public class ViewHolder extends RecyclerView.ViewHolder {
        // each data item is just a string in this case
        protected ImageView userAvatar;
        protected TextView userID;
        protected TextView userComment;

        public ViewHolder(View v) {
            super(v);
            userAvatar = (ImageView) findViewById(R.id.profile_image_avatar);
            userID = (TextView) findViewById(R.id.user_ID);
            userComment = (TextView) findViewById(R.id.user_comment);
        }
    }

    // Provide a suitable constructor (depends on the kind of dataset)
    public MyAdapter(ArrayList<Comments> myDataset) {
        mCommentArrayList = myDataset;
    }

    // Create new views (invoked by the layout manager)
    @Override
    public MyAdapter.ViewHolder onCreateViewHolder(ViewGroup parent,
                                                   int viewType) {
        // create a new view
        View v = LayoutInflater.from(parent.getContext())
                .inflate(R.layout.individual_comment, parent, false);
        // set the view's size, margins, paddings and layout parameters

        return new ViewHolder(v);
    }

    // Replace the contents of a view (invoked by the layout manager)

    @Override
    public void onBindViewHolder(ViewHolder holder, int position) {
        holder.userComment.setText(mCommentArrayList.get(position).getUserComment());
        holder.userID.setText(mCommentArrayList.get(position).getUserID());
    }

    // Return the size of your dataset (invoked by the layout manager)
    @Override
    public int getItemCount() {
        return mNumberOfCommentsAtPoll;
    }
}

最佳答案

在 RecycleViewAdapter 的 getItemCount() 中，您应该返回列表数据源大小

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

关于android - 动态 RecyclerView 不填充数据，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/37403181/