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。

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   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. [email protected]
   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. [email protected]
   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. [email protected]
   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. [email protected]
   52. ????public
       int getItemCount() {
   53. ????????return mDatas.size();
   54. ????}
   55. ?
   56. }

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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。