使用 ScrollView 的大列表

Question

我正在创建一个布局，其中我有大量要显示的项目，每个项目都包含一个具有 ImageView、EditText 和 TextView 的布局。理想情况下，这是 ListView 的完美候选者，但是，由于我有一个 EditText，当用户尝试键入某些内容时，我无法专注于它。在 SO 上阅读了很多关于此的帖子，似乎没有干净的解决方案来使用 ListView 实现此功能。

但是，我可能有 100 多个项目要显示，直接在 ScrollView 上渲染所有这些似乎不是一个明智的主意。是否有任何设计模式来处理这种情况？

Answer 1

您可以尝试使用RecycleView。它适用于大型数据集。 https://developer.android.com/training/material/lists-cards.html

"The RecyclerView widget is a more advanced and flexible version of ListView. This widget is a container for displaying large data sets that can be scrolled very efficiently by maintaining a limited number of views. Use the RecyclerView widget when you have data collections whose elements change at runtime based on user action or network events."

Answer 2

我想你需要的是新的RecyclerView that was recently added to the support library. A simple introduction is available here。

RecyclerView 特别有用，因为它没有 onItemClickListener。人们往往会问 "but why doesn't it have one?"

它实际上非常聪明，正是因为您的 use-case：它不会窃取您对可点击项目的关注（如您所知，ListView 会这样做），而是将每个点击事件委托给children 的 onClickListeners.

来自指定link的示例（来源是Antonio Leiva的博客）：

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

    private List<ViewModel> items;
    private int itemLayout;

    public MyRecyclerAdapter(List<ViewModel> items, int itemLayout) {
        this.items = items;
        this.itemLayout = itemLayout;
    }

    @Override public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View v = LayoutInflater.from(parent.getContext()).inflate(itemLayout, parent, false);
        return new ViewHolder(v);
    }

    @Override public void onBindViewHolder(ViewHolder holder, int position) {
        ViewModel item = items.get(position);
        holder.text.setText(item.getText());
        holder.image.setImageBitmap(null);
        Picasso.with(holder.image.getContext()).cancelRequest(holder.image);
        Picasso.with(holder.image.getContext()).load(item.getImage()).into(holder.image);
        holder.itemView.setTag(item);
    }

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

    public static class ViewHolder extends RecyclerView.ViewHolder {
        public ImageView image;
        public TextView text;

        public ViewHolder(View itemView) {
            super(itemView);
            image = (ImageView) itemView.findViewById(R.id.image);
            text = (TextView) itemView.findViewById(R.id.text);
        }
    }
}

add 和 remove 上的位置：

public void add(ViewModel item, int position) {
    items.add(position, item);
    notifyItemInserted(position);
}

public void remove(ViewModel item) {
    int position = items.indexOf(item);
    items.remove(position);
    notifyItemRemoved(position);
}

和初始化：

RecyclerView recyclerView = (RecyclerView) findViewById(R.id.list);
recyclerView.setHasFixedSize(true);  // use this setting to improve performance if you know that changes
                                     // in content do not change the layout size of the RecyclerView
recyclerView.setAdapter(new MyRecyclerAdapter(list, R.layout.item));
recyclerView.setLayoutManager(new LinearLayoutManager(this));
recyclerView.setItemAnimator(new DefaultItemAnimator());

需要依赖项：

dependencies {
    ...
    compile 'com.android.support:recyclerview-v7:21.0.+'
}

使用 ScrollView 的大列表

Large list using ScrollView

android

listview

scrollview