RecyclerView向下滚动，最多只有当刷新项目 [英] RecyclerView refreshes items only when scrolling down and up

问题描述

我正在使用影片的项目一个简单的recyclerview。当我尝试添加新项目，他们将不会在recyclerview显示的时候了。出于某种原因，我下来，第一个项目跑了，然后再为进行显示（它的索引0添加）新项目滚动。

I am making a simple recyclerview with Movie items. When I try adding new items they won't display in the recyclerview right away. For some reason I have to scroll down so the first item is gone, and then up again for the new item to be displayed (it's added at index 0).

适配器：

public class MovieCardAdapter extends RecyclerView.Adapter<MovieCardAdapter.MovieViewHolder> {
List<Movie> movieList;

public MovieCardAdapter(final List<Movie> movieList) {
    this.movieList = movieList;
}

public void addItem(int position, final Movie movie){
    movieList.add(position,movie);
    notifyItemInserted(position);
}

public void removeItem(final Movie movie){
    final int indexOf = movieList.indexOf(movie);
    movieList.remove(movie);
    notifyItemRemoved(indexOf);
}

public void updateItems(final List<Movie> items){
    movieList = items;
    notifyDataSetChanged();
}

@Override
public MovieViewHolder onCreateViewHolder(ViewGroup viewGroup, int i) {
    View itemView = LayoutInflater.
            from(viewGroup.getContext()).
            inflate(R.layout.movie_row, viewGroup, false);

    return new MovieViewHolder(itemView);
}

@Override
public long getItemId(int position) {
    return super.getItemId(position);
}

@Override
public void onBindViewHolder(final MovieViewHolder movieViewHolder, final int i) {
    final Movie movie = movieList.get(i);

    String posterUrl = "";
    final int posterHeight = 240;
    if (!isEmpty(movie.getImdb_id())) {
        posterUrl = "http://img.omdbapi.com/?i=" + movie.getImdb_id() + "&apikey="+apiKey+"&h=" + posterHeight;
    } else if (!isEmpty(movie.getPoster())) {
        posterUrl = movie.getPoster();
    }
    if (!isEmpty(posterUrl)) {
        Picasso.with(movieViewHolder.context)
                .load(posterUrl)
                .resize(220, 354)
                .centerCrop()
                .into(movieViewHolder.poster);
    }

    movieViewHolder.title.setText(movie.getTittel());
    movieViewHolder.format.setText(movie.getFormat());

    if (movie.getRuntime().isEmpty() || movie.getRuntime().equalsIgnoreCase("0")){
        movieViewHolder.runtime.setText("");
    }else{
        movieViewHolder.runtime.setText(movie.getRuntime()+" mins");
    }

    if (!movie.getTagline().isEmpty()) {
        movieViewHolder.tagline.setText(movie.getTagline());
    } else if (!movie.getPlot().isEmpty()) {
        movieViewHolder.tagline.setText(movie.getPlot());
    }
}

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

public static class MovieViewHolder extends RecyclerView.ViewHolder {
    protected Context context;
    protected LinearLayout movieRowLinearLayout;
    protected ImageView poster;
    protected TextView title;
    protected TextView runtime;
    protected TextView tagline;
    protected TextView format;

    public MovieViewHolder(View v) {
        super(v);
        context = v.getContext();
        movieRowLinearLayout = (LinearLayout) v.findViewById(R.id.movieRowLinearLayout);
        poster = (ImageView) v.findViewById(R.id.poster);
        title = (TextView) v.findViewById(R.id.title);
        runtime = (TextView) v.findViewById(R.id.runtime);
        tagline = (TextView) v.findViewById(R.id.tagline);
        format = (TextView) v.findViewById(R.id.format);
    }
}

}

初​​始化适配器：

adapter = new MovieCardAdapter(MovieList.movies);
recyclerView.setAdapter(adapter);

添加一个样本影片：

Adding a sample movie:

if (id == R.id.add_movie) {
        final Movie movie = new Movie();
        movie.setTittel("0TEST");
        movie.setFormat("HD-DVD");

        MovieList.sortMoviesByTitle();
        adapter.addItem(MovieList.movies.indexOf(movie), movie);
        return true;
    } else if (id == R.id.action_logOut) {
        logOut(this);
    }

Sry基因的英语不好，希望有人理解并知道问题可能是什么。
我试图从runOnUiThread（[...]），但同样的结果增加。

Sry bad english, hope someone understands and know what the problem might be. I have tried adding from runOnUiThread([...]), but same result.

推荐答案

这是发生，因为位置0是当前可见的屏幕上方。
直到谈话方式实现的，当你加入一个项目来定位 N ，尝试调用 scrollToPosition（N）如果 LinearLayoutManager＃findFirstCompletelyVisibleItemPosition 收益 N 。

This is happening because position 0 is above the current visible screen. Until transcript mode is implemented, when you are adding an item to position N, try calling scrollToPosition(N) if LinearLayoutManager#findFirstCompletelyVisibleItemPosition returns N.

另外，不要让位置参数最后在 onBindViewHolder 方法。相反，使用 ViewHolder.getPosition（）如果你需要它的回调。当该项目改变位置，你会不会，除非该项目本身是无效的接收onBind电话。

Also, don't make the position parameter final in your onBindViewHolder method. Instead, use ViewHolder.getPosition() if you need it in a callback. When position of the item changes, you will not receive an onBind call unless the item itself is invalidated.

更新

此外，您的更新逻辑是不正确的，因为你不是在视图中清除值。

Also your update logic is not correct because you are not clearing values in views.

if (!movie.getTagline().isEmpty()) {
    movieViewHolder.tagline.setText(movie.getTagline());
} else if (!movie.getPlot().isEmpty()) {
    movieViewHolder.tagline.setText(movie.getPlot());
} else {
    movieViewHolder.tagline.setText(null);
}

同样的海报URL。

Same for the poster URL.

这篇关于RecyclerView向下滚动，最多只有当刷新项目的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！