Question

ArrayList包含20个项目，我想显示从arraylist到Recycler视图的内容，有20个视图，我想添加一个页脚视图。但我得到了19个观点和页脚。这是Recycler View的Adapter类的代码。如果我增加了getItemCount的大小，我在BindViewHolder方法中得到indexoutofBound异常。请解决。

Result movie;
UrlConstants urlConstants = UrlConstants.getSingletonRef();
private ArrayList<Result> moviesList = new ArrayList<>();
private Context context;
private final int VIEW_ITEM = 0;
private final int VIEW_PROG = 1;
Fragment fragment;

public MoviesAdapter(ArrayList<Result> moviesList,Fragment fragment) {
    this.moviesList = moviesList;
    this.fragment = fragment;
}


public class MyViewHolder extends RecyclerView.ViewHolder {

    public ImageView backdrop_image;
    public TextView title, date;
    public MyViewHolder(View view) {
        super(view);
        backdrop_image = (ImageView)view.findViewById(R.id.backdrop_image);
        title = (TextView) view.findViewById(R.id.title);
        date = (TextView) view.findViewById(R.id.date);
    }
}

public class FooterViewHolder extends RecyclerView.ViewHolder
{
    public TextView tag_text,previous_page,next_page,between_text;

    public FooterViewHolder(View itemView) {
        super(itemView);
        between_text = (TextView) itemView.findViewById(R.id.between_text);
        tag_text = (TextView)itemView.findViewById(R.id.tag_text);
        previous_page = (TextView)itemView.findViewById(R.id.previous_page);
        next_page = (TextView) itemView.findViewById(R.id.next_page);

    }
}

@Override
public int getItemViewType(int position) {
    if (isPositionItem(position))
        return VIEW_ITEM;
    return VIEW_PROG;
}

private boolean isPositionItem(int position) {
    return position != getItemCount() -1;
}


@Override
public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {

    context = parent.getContext();

    if (viewType == VIEW_ITEM) {
        View v =  LayoutInflater.from(parent.getContext())
                .inflate(R.layout.movie_list_row, parent, false);
        return new MyViewHolder(v);
    } else if (viewType == VIEW_PROG){
        View v = LayoutInflater.from(parent.getContext())
                .inflate(R.layout.footer_layout, parent, false);
        return new FooterViewHolder(v);
    }

    return null;
}


@Override
public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) {


    if (holder instanceof MyViewHolder)
    {
        movie = moviesList.get(position);
        ((MyViewHolder)holder).title.setText(movie.getTitle());
        ((MyViewHolder)holder).date.setText(movie.getReleaseDate());
        String url = urlConstants.URL_Image + movie.getBackdropPath();
        Picasso.with(context)
                .load(url)
                .into(((MyViewHolder)holder).backdrop_image);
    }

    else if (holder instanceof FooterViewHolder)
    {
        movie = moviesList.get(position);


        ((FooterViewHolder)holder).tag_text.setText("Viewing " + movie.getPage() + " of " + movie.getTotal_pages() + " Pages" );
        ((FooterViewHolder)holder).previous_page.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v)
            {
                ((MoviesMainFragment)fragment).prepareOnlineData(movie.getPage() - 1);
            }
        });
        ((FooterViewHolder)holder).next_page.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                ((MoviesMainFragment)fragment).prepareOnlineData(movie.getPage() + 1);
            }
        });
    }
}

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

Answer 1

您必须将movilist大小增加1.为此，您必须将虚拟数据插入列表的最后一项，以便最后一项不具有空数据，并且您不会获得Indexoutofbound。

无需增加大小getItemCount，您已经在列表中添加了虚拟项目。

Answer 2

<强>问题

这一行

return position != getItemCount() -1;

你有20个项目，即item0..item19。以上仅检查19项，即最多项目18。当回收者视图到达最后一个位置时，根据条件，它将使页脚视图膨胀，从而忽略最后一个项目。

<强>解决方案

下面的代码适用于我。

更改您的isPositionItem()方法，如下所示

private boolean isPositionItem(int position) {
    return position == moviesList.size();
}

更改您的getItemCount()，如下所示

@Override
public int getItemCount()
{
   return this.moviesList.size()+1;
}

在Android中的循环器视图中有20个视图可以充气和页脚视图，但是回收器视图正在充气19个视图加上页脚视图

2 个答案: