概述:
RecyclerView是android-support-v7-21版本中新增的一个Widgets,RecyclerView是ListView的升级版本,更加先进和灵活。在以后的开发中我们就可以直接使用RecyclerView来替换ListView。
特点介绍:
1. 可横向展示
2. 消除错位问题
3. 标准化了ViewHolder
横向:
private void initHorizaontal(List<ItemModel> models) { RecyclerView recyclerView = (RecyclerView) findViewById(R.id.activity_main_horizontal_recyclerview); LinearLayoutManager layoutManager = new LinearLayoutManager(MainActivity.this); layoutManager.setOrientation(LinearLayoutManager.HORIZONTAL); recyclerView.setLayoutManager(layoutManager); RecyclerViewAdapter adapter = new RecyclerViewAdapter(MainActivity.this, models); recyclerView.setAdapter(adapter); }
竖向:
public void initVertical(List<ItemModel> models) { RecyclerView recyclerView = (RecyclerView) findViewById(R.id.activity_main_vertical_recyclerview); LinearLayoutManager layoutManager = new LinearLayoutManager(MainActivity.this); layoutManager.setOrientation(LinearLayoutManager.VERTICAL); recyclerView.setLayoutManager(layoutManager); RecyclerViewAdapter adapter = new RecyclerViewAdapter(MainActivity.this, models); recyclerView.setAdapter(adapter); }
Adapter的变化:
Google在对RecyclerView的改进中还为我们解决了一个初学者比较头痛的问题:错位。
public class RecyclerViewAdapter extends RecyclerView.Adapter<ViewHolder> { private List<ItemModel> mList = null; private Context mContext = null; private LayoutInflater mInflater = null; public RecyclerViewAdapter(Context context, List<ItemModel> list) { mContext = context; mList = list; mInflater = LayoutInflater.from(mContext); } @Override public int getItemCount() { if (mList != null) { return mList.size(); } return 0; } @Override public void onBindViewHolder(ViewHolder viewHolder, int position) { ((ItemViewHolder)viewHolder).mLabelTextView.setText(mList.get(position).getLabel()); } @Override public ViewHolder onCreateViewHolder(ViewGroup viewGroup, int arg1) { View view = mInflater.inflate(R.layout.list_item, viewGroup, false); ItemViewHolder holder = new ItemViewHolder(view); holder.mLabelTextView = (TextView) view.findViewById(R.id.list_item_textview); return holder; } public static class ItemViewHolder extends ViewHolder{ public ItemViewHolder(View itemView) { super(itemView); } private TextView mLabelTextView = null; } }
上拉或下拉刷新:
对于下拉刷新,Android自身有一个控件SwipeRefreshLayout已经有所实现。我们把SwipeRefreshLayout包在RecyclerView的外面,然后再设置其绑定到一个OnRefreshListener上。
布局:
<android.support.v4.widget.SwipeRefreshLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:id="@+id/swipe_refresh_widget" android:layout_width="match_parent" android:layout_height="match_parent" > <android.support.v7.widget.RecyclerView android:id="@android:id/list" android:layout_width="match_parent" android:layout_height="match_parent" android:cacheColorHint="@null" android:scrollbars="vertical" /> </android.support.v4.widget.SwipeRefreshLayout>
监听:
@Override public void onRefresh() { handler.sendEmptyMessageDelayed(0, 3000); }
而对于上拉刷新,我们则是自定义一个FooterView和线程来进行的。
mRecyclerView.setOnScrollListener(new RecyclerView.OnScrollListener() { @Override public void onScrollStateChanged(RecyclerView recyclerView, int newState) { super.onScrollStateChanged(recyclerView, newState); if (newState == RecyclerView.SCROLL_STATE_IDLE && lastVisibleItem + 1 == adapter.getItemCount()) { handler.sendEmptyMessageDelayed(1, 3000); } } @Override public void onScrolled(RecyclerView recyclerView, int dx, int dy) { super.onScrolled(recyclerView, dx, dy); lastVisibleItem = mLayoutManager.findLastVisibleItemPosition(); } });
相关源码下载: