Android 【实现自动轮询的RecycleView】

需求：类似医院或者商场，大屏幕无限轮播item (广告词/广告图…)

代码如下

/**
 * Created by Xia_焱 on 2017/8/20.
 */

public class AutoPollRecyclerView extends RecyclerView {
    private static final long TIME_AUTO_POLL = 32;
    AutoPollTask autoPollTask;
    private boolean running; //标示是否正在自动轮询
    private boolean canRun;//标示是否可以自动轮询,可在不需要的是否置false
    public AutoPollRecyclerView(Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
        autoPollTask = new AutoPollTask(this);
    }
    static class AutoPollTask implements Runnable {
        private final WeakReference<AutoPollRecyclerView> mReference;
        //使用弱引用持有外部类引用->防止内存泄漏
        public AutoPollTask(AutoPollRecyclerView reference) {
            this.mReference = new WeakReference<AutoPollRecyclerView>(reference);
        }
        @Override
        public void run() {
            AutoPollRecyclerView recyclerView = mReference.get();
            if (recyclerView != null &&  recyclerView.running &&recyclerView.canRun) {
                recyclerView.scrollBy(2, 2);
                recyclerView.postDelayed(recyclerView.autoPollTask,recyclerView.TIME_AUTO_POLL);
            }
        }
    }
    //开启:如果正在运行,先停止->再开启
    public void start() {
        if (running)
            stop();
        canRun = true;
        running = true;
        postDelayed(autoPollTask,TIME_AUTO_POLL);
    }
    public void stop(){
        running = false;
        removeCallbacks(autoPollTask);
    }
    @Override
    public boolean onTouchEvent(MotionEvent e) {
        switch (e.getAction()){
            case MotionEvent.ACTION_DOWN:
                if (running)
                    stop();
                break;
            case MotionEvent.ACTION_UP:
            case MotionEvent.ACTION_CANCEL:
            case MotionEvent.ACTION_OUTSIDE:
                if (canRun)
                    start();
                break;
        }
        return super.onTouchEvent(e);
    }
}

开启:如果正在运行,先停止->再开启

  public void start() {
        if (running)
            stop();
        canRun = true;
        running = true;
        postDelayed(autoPollTask,TIME_AUTO_POLL);
    }
    public void stop(){
        running = false;
        removeCallbacks(autoPollTask);
    }
    @Override
    public boolean onTouchEvent(MotionEvent e) {
        switch (e.getAction()){
            case MotionEvent.ACTION_DOWN:
                if (running)
                    stop();
                break;
            case MotionEvent.ACTION_UP:
            case MotionEvent.ACTION_CANCEL:
            case MotionEvent.ACTION_OUTSIDE:
                if (canRun)
                    start();
                break;
        }
        return super.onTouchEvent(e);
    }
}

Adapter中的代码如下

    @Override
    public void onBindViewHolder(BaseViewHolder holder, int position) {
        String data = mData.get(position%mData.size());
        holder.setText(R.id.tv_content,data);
    }
    @Override
    public int getItemCount() {
        return Integer.MAX_VALUE;
    }

Activity中的代码

  mRecyclerView.setAdapter(adapter);
        if (true) //保证itemCount的总个数宽度超过屏幕宽度->自己处理
            mRecyclerView.start();