Question

适配器类

public class ItemAdapter extends RecyclerView.Adapter<ItemAdapter.MyHolder> {
private RecyclerviewListener mlistener;
private Context context;
private ArrayList<ItemModel> data = new ArrayList<>();

public ItemAdapter(Context context, ArrayList<ItemModel> data, RecyclerviewListener mlistener) {
    this.mlistener = mlistener;
    this.context = context;
    this.data = data;

}



@NonNull
@Override
public MyHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
    View v;
    LayoutInflater inflater = LayoutInflater.from(context);
    v = inflater.inflate(R.layout.item_adapter, parent, false);
    final ItemAdapter.MyHolder myHolder = new ItemAdapter.MyHolder(v);
    v.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            mlistener.onClick(view, myHolder.getAdapterPosition());
        }
    });

    return myHolder;


}

@Override
public void onBindViewHolder(@NonNull final MyHolder holder, int position) {
    ItemModel i = data.get(position);
    RequestOptions requestOptions = new RequestOptions();
    requestOptions.placeholder(R.drawable.image_holder2);


    // make sure Glide doesn't load anything into this view until told otherwise
    // remove the placeholder (optional); read comments below
    holder.imageView.setImageDrawable(null);Glide.with(context).setDefaultRequestOptions(requestOptions).load(i.getImage1()).into(holder.imageView); }

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

class MyHolder extends RecyclerView.ViewHolder {
    public ImageView imageView;

    public MyHolder(View itemView) {
        super(itemView);
        imageView = itemView.findViewById(R.id.imageView);

    }
}}

*每当我快速向下滚动时。Recyclerview两次显示相同的项目，我尝试了许多解决方案，但没有人在工作*

首先用于检索数据并获取最后检索到的文档的方法，即lastVisible变量

  private void getData() {
    Query data = firestore.collection("Madhya Pradesh").document(cityname).collection("Product").document(category).collection("View").limit(3);
    data.get().addOnCompleteListener(new OnCompleteListener<QuerySnapshot>() {
        @Override
        public void onComplete(@NonNull Task<QuerySnapshot> task) {

            if (task.isSuccessful()) {
                QuerySnapshot d = task.getResult();
                lastVisible = d.getDocuments()
                        .get(d.size() - 1);

                for (DocumentSnapshot doc : task.getResult()) {


                    ItemModel item = new ItemModel();

                    if (doc.getString("Image1") != null) {
                        item.setImage1(doc.getString("Image1"));
                    } else {
                        item.setImage1("null");
                    }

                    rdata.add(item);
                    itemAdapter.notifyDataSetChanged();

                }

            } else {
                // error from firebase handle it;

            }

        }
    });


}

查询方法（Firebase），用于在滚动时检索数据

private void scroll() {


    itemRView.addOnScrollListener(new RecyclerView.OnScrollListener() {
        @Override
        public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
            super.onScrollStateChanged(recyclerView, newState);
            if (newState == AbsListView.OnScrollListener.SCROLL_STATE_TOUCH_SCROLL) {
                isScrolling = true;
            }
        }

        @Override
        public void onScrolled(RecyclerView recyclerView, int dx, int dy) {
            super.onScrolled(recyclerView, dx, dy);

            currentitem = manager.getChildCount();
            totalitem = manager.getItemCount();
            scrollOutitem = manager.findFirstVisibleItemPosition();


            if (isScrolling && (currentitem + scrollOutitem == totalitem)) {
                progressBar.setVisibility(View.VISIBLE);
                isScrolling = false;

                final Query data = firestore.collection("State").document(cityname).collection("Product").document(category).collection("View").startAfter(lastVisible).limit(2);


                data.get().addOnCompleteListener(new OnCompleteListener<QuerySnapshot>() {
                    @Override
                    public void onComplete(@NonNull Task<QuerySnapshot> task) {
                        QuerySnapshot d = task.getResult();
                        lastVisible = d.getDocuments()
                                .get(d.size() - 1);

                        if (task.isSuccessful() && !task.getResult().isEmpty()) {
                            progressBar.setVisibility(View.GONE);
                            for (DocumentSnapshot doc : task.getResult()) {


                                ItemModel item = new ItemModel();

                                if (doc.getString("Image1") != null) {
                                    item.setImage1(doc.getString("Image1"));
                                } else {
                                    item.setImage1("null");
                                }



                                rdata.add(item);
                                itemAdapter.notifyDataSetChanged();
                            }

                        }

                    }
                });


            }


        }

    });


}

Answer 1

问题可能出在滚动过程中。在滚动RecyclerView时，将重新绑定Holder并执行“ onBindViewHolder（..）”，因此，如果您只想在滚动过程中加载新的可见行（不做任何特殊操作），则可以删除滚动过程。

图像复制Recyclerview

1 个答案: