Question

我正在使用RecyclerView显示项目，这些项目也可以通过点击每个元素名称附近的相应图标（颜色变为黄色）保存为收藏夹。我还在Recyclerview的底部使用无尽的ProgressBar来加载更多项目。

问题在于，当我将项目保存为收藏时，不同位置的其他图标变为黄色。经过一些测试后，我发现它只是一个RecyclerView问题，因为收藏夹在我的列表和我的xml文件中都得到了正确的保存。没有无尽的ProgressBar一切正常。

所以我认为我没有正确处理这两个ViewHolder。有关如何解决它的任何想法？

@Override
public RecyclerView.ViewHolder onCreateViewHolder(final ViewGroup viewGroup, int viewType) {
    if(pt_list.size() > 0){
        if (viewType == VIEW_TYPE_ITEM) {

            View itemView = LayoutInflater.
                    from(viewGroup.getContext()).
                    inflate(R.layout.pt_item_list_layout, viewGroup, false);
            return new ListViewHolder(itemView);

        } else if (viewType == VIEW_TYPE_LOADING) {
            View view = LayoutInflater.from(viewGroup.getRootView().getContext())
                    .inflate(R.layout.pt_list_footer_loading, viewGroup, false);
            return new LoadingViewHolder(view);
        }
    }
    return null;
}

OnBindViewHolder：

public void onBindViewHolder(RecyclerView.ViewHolder viewHolder, int position) {

    if (viewHolder instanceof ListViewHolder) {

        final ListViewHolder holder = (ListViewHolder) viewHolder;
        final PublicTransport pt = pt_list.get(holder.getAdapterPosition());

        holder.pt_name.setText(pt.getPt_name());
        holder.pt_route.setText(pt.getPt_route());

        //set fav_img
        for(int i = 0; i < fav_list.size(); i++){
            if(fav_list.get(i).equals(pt)){
                holder.fav_img.setImageResource(R.drawable.ic_favorites_star_full);
            } else{
                holder.fav_img.setImageResource(R.drawable.ic_favorites_star_empty);
            }
        }

        //item click listener
        holder.itemView.setOnClickListener(new View.OnClickListener() {
            ...
        });

        //save/ delete favorites by tapping on the icon
        holder.fav_img.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                if (holder.fav_img.getDrawable().getConstantState().equals(//it is not a favorite
                        ContextCompat.getDrawable(v.getContext(),
                                R.drawable.ic_favorites_star_empty).getConstantState())) {


                    if (addFav(pt)) {
                        //change icon image
                        holder.fav_img.setImageResource(R.drawable.ic_favorites_star_full);
                        //notify the user ...
                    } else {
                        //keep the same image
                        holder.fav_img.setImageResource(R.drawable.ic_favorites_star_empty)
                        //notify the user ...
                    }

                } else {//it is a favorite
                    if (removeFav(pt)) {
                        //change icon image
                        holder.fav_img.setImageResource(R.drawable.ic_favorites_star_empty);
                        //notify the user ...
                    } else {
                        //keep the same image
                        holder.fav_img.setImageResource(R.drawable.ic_favorites_star_full);
                        //notify the user ...
                    }

                }
            }
        });

    } else if (viewHolder instanceof LoadingViewHolder) {//endless ProgressBar
        LoadingViewHolder loadingViewHolder = (LoadingViewHolder) viewHolder;
        loadingViewHolder.progressBar.setIndeterminate(true);
    }
}

如果需要，请参阅我的活动中的ProgressBar实现：

publicTransportListAdapter.setOnLoadMoreListener(new OnLoadMoreListener() {
        @Override
        public void onLoadMore() {
            //add ProgressBar to RecyclerView
            pt_list.add(null);
            publicTransportListAdapter.notifyItemInserted(pt_list.size() - 1);

            //Load more data for recyclerview
            new Handler().postDelayed(new Runnable() {
                @Override
                public void run() {
                    //load more items from server (via thread)
                    loadMore();

                    //remove ProgressBar
                    pt_list.remove(pt_list.size() - 1);
                    publicTransportListAdapter.notifyItemRemoved(pt_list.size());

                }
            }, 2000);
        }
    });

Answer 1

问题是你正在根据fav_img drawable检查项目是否是最喜欢的：

if (holder.fav_img.getDrawable().getConstantState().equals(//it is not a favorite
                    ContextCompat.getDrawable(v.getContext(),
                            R.drawable.ic_favorites_star_empty).getConstantState()))

RecyclerView，正如其名称所示，回收视图，因此您可以收到不喜欢的项目的收藏项目视图，并且您的检查返回错误的值。

为了解决这个问题，在onClickListener中你应该检查你的fav_list，如果该项是最喜欢的：

PublicTransport pubTransp = pt_list.get(holder.getAdapterPosition());
for(int i = 0; i < fav_list.size(); i++){
    if(fav_list.get(i).equals(pubTransp)){
        // check if it is favorite
    }
}

使用recyclerview和收藏夹的Android问题

1 个答案: