概要

做一个自动滑动的列表，用于展示聊天记录或者通知栏信息等，还是使用主流的RecyclerView来做。网上有很多案例，但当手动滑动时会一直无限循环，数据重复的出现，如果想要自动滑动时能无限循环，手动滑动时又能滑到底呢？本案例就解决这种手动滑动和自动滑动无缝衔接的问题。

思路

1、重写RecyclerView，通过scrollBy和postDelayed进行定时移动到达自动滑动目的

2、RecyclerView添加addOnScrollListener，进行手指按下滑动和抬起监听，用于判断是手动滑动还是自动滑动。

3、修改adapter的itemCount

4、接下来上代码

实现方案

1、重写 RecyclerView：

public class SocllRecyclerView extends RecyclerView {private Autoaaview autoview;private boolean running;private boolean canrun;private static final int Timea = 40;//控制滚动的速度，值越大速度越慢public SocllRecyclerView(@NonNull Context context, @Nullable AttributeSet attrs) {super(context, attrs);autoview = new Autoaaview(this);}public SocllRecyclerView(@NonNull Context context, @Nullable AttributeSet attrs, int defStyle) {super(context, attrs, defStyle);}private class Autoaaview implements Runnable{WeakReference<SocllRecyclerView> myScrViewWeakReference;public Autoaaview(SocllRecyclerView myScrView) {myScrViewWeakReference = new WeakReference<>(myScrView);}@Overridepublic void run() {SocllRecyclerView myScrView = myScrViewWeakReference.get();if (myScrView.canrun&&myScrView.running){myScrView.scrollBy(2,2);myScrView.postDelayed(myScrView.autoview,Timea);}}}//开始滚动public void start(){if (running)stop();running = true;canrun = true;postDelayed(autoview,Timea);}//停止滚动public void stop() {running = false;removeCallbacks(autoview);}@Overridepublic boolean onTouchEvent(MotionEvent e) {return super.onTouchEvent(e);}
}

2、适配器 MyscrviewAdapter

public class MyscrviewAdapter extends RecyclerView.Adapter<ViewHolder> {Context context;List<NoticeBean.RecordsBean> mies;private int itemCount = Integer.MAX_VALUE;public MyscrviewAdapter(Context context, List<NoticeBean.RecordsBean> mies) {this.context = context;this.mies = mies;}public void updateAll(List<NoticeBean.RecordsBean> list) {mies.clear();mies.addAll(list);notifyDataSetChanged();}/*** 设置状态，用于设置ItemCount的数量* state：1 表示正在手指滑动，itemCount设置为实际数量；* 其他的表示结束手动滑动，itemCount设置为最大值Integer.MAX_VALUE* @param state*/public void setItemCount(int state) {this.itemCount = state == 1 ? mies.size() : Integer.MAX_VALUE;notifyDataSetChanged();}@NonNull@Overridepublic ViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {View inflate = LayoutInflater.from(context).inflate(R.layout.item_home_news, parent, false);ViewHolder baseViewHolder = new ViewHolder(inflate);return baseViewHolder;}@Overridepublic void onBindViewHolder(@NonNull ViewHolder holder, final int position) {holder.setText(R.id.tvNewsTitle, mies.get(position % mies.size()).getTitle());holder.itemView.setOnClickListener(new View.OnClickListener() {@Overridepublic void onClick(View v) {if (null != mItemClickListener) {mItemClickListener.onItemClick(mies.get(position % mies.size()), position);}}});}@Overridepublic int getItemCount() {return mies.size() > 4 ? itemCount : mies.size();}//使用接口回调点击事件private ItemClickListener mItemClickListener;public void setOnItemClickListener(ItemClickListener itemClickListener) {this.mItemClickListener = itemClickListener;}public interface ItemClickListener {void onItemClick(Object obj, int position);}
}

ViewHolder封装类

public class ViewHolder extends RecyclerView.ViewHolder {//用于缓存已找的界面private SparseArray<View> mView;public ViewHolder(View itemView) {super(itemView);mView=new SparseArray<>();}public <T extends View> T getView(int viewId){//对已有的view做缓存View view=mView.get(viewId);//使用缓存的方式减少findViewById的次数if(view==null){view=itemView.findViewById(viewId);mView.put(viewId,view);}return (T) view;}//通用的功能进行封装  设置文本 设置条目点击事件  设置图片public ViewHolder setText(int viewId , CharSequence text){TextView view = getView(viewId);view.setText(text);//希望可以链式调用return this;}//通用的功能进行封装  设置文本 设置条目点击事件  设置图片public ViewHolder setText(int viewId , String text){TextView view = getView(viewId);view.setText(text);//希望可以链式调用return this;}public ViewHolder setSelected(int viewId ,boolean selected){TextView view = getView(viewId);view.setSelected(selected);//希望可以链式调用return this;}public ViewHolder setSelected2(int viewId,boolean selected){View view = getView(viewId);view.setSelected(selected);return this;}public ViewHolder setVisible(int viewId,boolean visible){View view = getView(viewId);view.setVisibility(visible ? View.VISIBLE : View.GONE);return this;}public ViewHolder setVisible(int viewId,boolean visible,boolean isLocation){View view = getView(viewId);if (isLocation){view.setVisibility(visible ? View.VISIBLE : View.INVISIBLE);}else{view.setVisibility(visible ? View.VISIBLE : View.GONE);}return this;}/***设置本地图片* @param viewId* @param resId* @return*/public ViewHolder setImageResource(int viewId,int resId){ImageView iv=getView(viewId);iv.setImageResource(resId);return this;}public ViewHolder setTextSelected(int viewId, boolean bool) {TextView tv = getView(viewId);tv.setSelected(bool);return this;}/***设置本地图片* @param viewId* @param resId* @return*/public ViewHolder setImageDrawable(Context mContext, int viewId, int resId){ImageView iv=getView(viewId);iv.setImageDrawable(mContext.getResources().getDrawable(resId));return this;}/*** 加载图片资源路径* @param viewId* @param imageLoader* @return*/public ViewHolder setImagePath(int viewId,HolderImageLoader imageLoader,int res){ImageView iv=getView(viewId);imageLoader.loadImage(iv,imageLoader.getPath(),res);return this;}public ViewHolder setImage(Context mContext, int viewId, String url, int res) {ImageView view = getView(viewId);GlideLoadImageUtils.loadRectangleImg(mContext, view, url,res);return this;}public ViewHolder setCircleImage(Context mContext, int viewId, String url, int res) {ImageView view = getView(viewId);GlideLoadImageUtils.loadCircleImg(mContext, view, url,res);return this;}public ViewHolder setTextColor(Context mContext, int viewId, int color) {TextView tv = (TextView)this.getView(viewId);tv.setTextColor(mContext.getResources().getColor(color));return this;}public ViewHolder setTextSize(Context mContext, int viewId, float res) {TextView tv = (TextView)this.getView(viewId);tv.setTextSize(Utils.dp2px(mContext,res));return this;}@SuppressLint("NewApi")public ViewHolder setBackground(Context mContext, int viewId, int bg) {TextView tv = (TextView)this.getView(viewId);tv.setBackground(mContext.getResources().getDrawable(bg));return this;}/*** 关于事件的*/public ViewHolder setOnClickListener(int viewId, View.OnClickListener listener) {View view = getView(viewId);view.setOnClickListener(listener);return this;}public abstract static class HolderImageLoader{public String mPath;public Context mContext;public HolderImageLoader(Context mContext, String path){this.mPath=path;this.mContext = mContext;}/*** 需要去复写这个方法加载图片* @param iv* @param path*/public abstract void loadImage(ImageView iv, String path, int res);public String getPath(){return mPath;}}}

3、activity中使用

     RecyclerView滑动监听，注释都说的很详细

/*** 控制通知公告数据滚动* 手指滑动时 停止自动滚动* 手指抬起时，3秒后自动开始滚动*/private void initRlvNews() {scroHandler = new Handler();//定义handlerrunnable = () -> {  //runnable方法，处理延时后的操作newsAdapter.setItemCount(0);//0表示手指已经抬起来了rlvNews.start(); //开始滑动};rlvNews.addOnScrollListener(new RecyclerView.OnScrollListener() {@Overridepublic void onScrollStateChanged(@NonNull RecyclerView recyclerView, int newState) {super.onScrollStateChanged(recyclerView, newState);if (null != newsAdapter) {if (newState == 1) {//newState的值：1 手指按下拖拽滚动，2自动滚动(一般指惯性滚动)，0 禁止没有滚动rlvNews.stop();//停止自动滚动newsAdapter.setItemCount(newState);} else {scroHandler.removeCallbacks(runnable);//清除runnable重新开始//这里设置3秒是预估了手指滑动抬起再滑动的时间，提升体验scroHandler.postDelayed(runnable, 3000);}}}});}

4、布局文件：

  需要给固定高度

<com.anyi.credit.bank.view.SocllRecyclerViewandroid:id="@+id/rlvNews"android:layout_width="match_parent"android:layout_height="144dp"/>

5、数据绑定

         rlvNews.setLayoutManager（）//可设置水平滚动或竖直滚动布局

        MyscrviewAdapter adpter=new MyscrviewAdapter(this,list)

        rlvNews.setAdapter(adpter)

        //关键，条件自定义，如当列表数据大于4条时开始滑动

        if（list.size()>4）{

                rlvNews.start(); //开始滑动

        }

结束------------