Android新控件RecyclerView浅析及上拉和下拉刷新

2015-09-10 00:18:11   来源:   评论: 点击:

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。

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:

RecyclerView初步使用

RecyclerView的上拉和下拉刷新


Android新控件RecyclerView浅析及上拉和下拉刷新

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