用recyclerview实现跑马灯文字无限轮播

网上找了一些跑马灯实现都是直接重写的textview不停的改变绘制文字的位置来达到跑马灯效果，但是有的时候需求要求来回滚动多条信息，用textview实现的就不尽人意了，于是用recyclerview整理了一个
思路就是利用recyclerview的scrollBy不停的滚动，来达到效果

recyclerview代码

import android.content.Context;
import android.util.AttributeSet;
import android.view.MotionEvent;

import androidx.annotation.Nullable;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

import com.cy.utils.LogUtil;

import java.lang.ref.WeakReference;

public class AutoPollRecyclerView extends RecyclerView {
    private static final long TIME_AUTO_POLL = 10;
    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) {
                LinearLayoutManager layoutManager = (LinearLayoutManager) recyclerView.getLayoutManager();
                int lastVisibleItemPosition = layoutManager.findLastVisibleItemPosition();
                if (lastVisibleItemPosition == (Integer.MAX_VALUE - 1))//如果真有人等到一直滚动到最大值那就让他回到头部重新滚
                    recyclerView.scrollToPosition(0);
                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) {
        //若果需要触摸停止就把这里打开
//        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 false;
    }
}

其中要注意recyclerview的adapter里面的getItemCount方法要写成最大值，

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

    @Override
    public int getItemCount() {
        return Integer.MAX_VALUE;
    }