RecyclerView 介绍 01

RecyclerView是Android support v7里面是一个自定义控件。用来显示大量数据集合。类似ListView和GridView这两个控件，RecyclerView同样可以实现，甚至更好。

以前我们在实现ListView和GridView的时候，都会定义一个ViewHolder用于优化UI性能【详见】，RecycleView的实现，已经是自带ViewHolder的实现。请看示例。

1. 实现Adapter，定义每个Item的布局UI和数据。
   1. public class MyRecyclerAdapter extends RecyclerView.Adapter<MyRecyclerAdapter.ViewHolder> {
   2.  
   3.     private List<String> mDatas = new ArrayList<>(0);
   4.  
   5.     public MyRecyclerAdapter(List<String> datas) {
   6.         if (datas != null) {
   7.             mDatas.addAll(datas);
   8.         }
   9.     }
   10.  
   11.     public static final class ViewHolder extends RecyclerView.ViewHolder {
   12.  
   13.         private final TextView textView;
   14.         private final Button button;
   15.  
   16.  
   17.         public ViewHolder(View itemView) {
   18.             super(itemView);
   19.             textView = (TextView) itemView.findViewById(R.id.item_text);
   20.             button = (Button) itemView.findViewById(R.id.item_button);
   21.             button.setOnClickListener(new View.OnClickListener() {
   22.  
   23.                 @Override
   24.                 public void onClick(View v) {
   25.                     Toast.makeText(v.getContext(), String.valueOf(getPosition()), Toast.LENGTH_SHORT).show();
   26.                 }
   27.             });
   28.         }
   29.  
   30.         public TextView getTextView() {
   31.             return textView;
   32.         }
   33.  
   34.         public Button getButton() {
   35.             return button;
   36.         }
   37.     }
   38.  
   39.     @Override
   40.     public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
   41.         View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.item, null);
   42.         return new ViewHolder(view);
   43.     }
   44.  
   45.     @Override
   46.     public void onBindViewHolder(ViewHolder holder, int position) {
   47.         holder.getButton().setText(String.valueOf(position));
   48.         holder.getTextView().setText(mDatas.get(position));
   49.     }
   50.  
   51.     @Override
   52.     public int getItemCount() {
   53.         return mDatas.size();
   54.     }
   55.  
   56. }
2. 初始化RecyclerView

   设置Adapter和LayoutManager。LayoutManager定义了每个Item的排列形式。官方提供两种实现，LinearLayoutManager和GridLayoutManager，当然我们也可以根据需求，自己实现LayoutManager。

   1. recyclerView = (RecyclerView) findViewById(R.id.recycler);
   2. MyRecyclerAdapter adapter = new MyRecyclerAdapter(Datas.getDatas(1000));
   3. RecyclerView.LayoutManager layoutManager = new LinearLayoutManager(this,LinearLayoutManager.VERTICAL,false);
   4. recyclerView.setLayoutManager(layoutManager);
   5. recyclerView.setAdapter(adapter);

RecyclerView就是这么简单。

源码：GitHub