Android新控件RecyclerView浅析及上拉和下拉刷新 概述： 特点介绍： 横向： 竖向： 上拉或下拉刷新： 相关源码下载：
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:andro
xmlns:tools="http://schemas.android.com/tools"
android:
android:layout_width="match_parent"
android:layout_height="match_parent" >
<android.support.v7.widget.RecyclerView
android:
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();
}
});