public class LeftSnapHelper extends LinearSnapHelper {

 private OrientationHelper mHorizontalHelper;

 /**
 * 当拖拽或滑动结束时会回调该方法,该方法返回的是一个长度为2的数组,out[0]表示横轴,x[1]表示纵轴,这两个值就是你需要修正的位置的偏移量
 *
 * @param layoutManager
 * @param targetView
 * @return
 */
 @Override
 public int[] calculateDistanceToFinalSnap(RecyclerView.LayoutManager layoutManager, View targetView) {
 //注:由于是横向滚动,在这里我们只考虑横轴的值
 int[] out = new int[2];
 if (layoutManager.canScrollHorizontally()) {
  out[0] = distanceToStart(targetView, getHorizontalHelper(layoutManager));
 } else {
  out[0] = 0;
 }
 return out;
 }

 /**
 * 这个方法是计算偏移量
 *
 * @param targetView
 * @param helper
 * @return
 */
 private int distanceToStart(View targetView, OrientationHelper helper) {
 return helper.getDecoratedStart(targetView) - helper.getStartAfterPadding();
 }

 @Override
 public View findSnapView(RecyclerView.LayoutManager layoutManager) {
 return findStartView(layoutManager, getHorizontalHelper(layoutManager));
 }

 /**
 * 找到第一个显示的view
 * @param layoutManager
 * @param helper
 * @return
 */
 private View findStartView(RecyclerView.LayoutManager layoutManager,
    OrientationHelper helper) {
 if (layoutManager instanceof LinearLayoutManager) {
  int firstChild = ((LinearLayoutManager) layoutManager).findFirstVisibleItemPosition();
  int lastChild = ((LinearLayoutManager) layoutManager).findLastVisibleItemPosition();
  if (firstChild == RecyclerView.NO_POSITION) {
  return null;
  }

  //这是为了解决当翻到最后一页的时候，最后一个Item不能完整显示的问题
  if (lastChild == layoutManager.getItemCount() - 1) {
  return layoutManager.findViewByPosition(lastChild);
  }
  View child = layoutManager.findViewByPosition(firstChild);

  //得到此时需要左对齐显示的条目
  if (helper.getDecoratedEnd(child) >= helper.getDecoratedMeasurement(child) / 2
   && helper.getDecoratedEnd(child) > 0) {
  return child;
  } else {
  return layoutManager.findViewByPosition(firstChild + 1);
  }
 }
 return super.findSnapView(layoutManager);
 }

 /**
 * 获取视图的方向
 *
 * @param layoutManager
 * @return
 */
 private OrientationHelper getHorizontalHelper(@NonNull RecyclerView.LayoutManager layoutManager) {
 if (mHorizontalHelper == null) {
  mHorizontalHelper = OrientationHelper.createHorizontalHelper(layoutManager);
 }
 return mHorizontalHelper;
 }
}

public class RightSnapHelper extends LinearSnapHelper {

 private OrientationHelper mHorizontalHelper;

 /**
 * 当拖拽或滑动结束时会回调该方法,该方法返回的是一个长度为2的数组,out[0]表示横轴,x[1]表示纵轴,这两个值就是你需要修正的位置的偏移量
 *
 * @param layoutManager
 * @param targetView
 * @return
 */
 @Override
 public int[] calculateDistanceToFinalSnap(RecyclerView.LayoutManager layoutManager, View targetView) {
 //注:由于是横向滚动,在这里我们只考虑横轴的值
 int[] out = new int[2];
 if (layoutManager.canScrollHorizontally()) {
  out[0] = distanceToEnd(targetView, getHorizontalHelper(layoutManager));
 } else {
  out[0] = 0;
 }
 return out;
 }

 /**
 * 这个方法是计算偏移量
 *
 * @param targetView
 * @param helper
 * @return
 */
 private int distanceToEnd(View targetView, OrientationHelper helper) {
 return helper.getDecoratedEnd(targetView) - helper.getEndAfterPadding();
 }

 @Override
 public View findSnapView(RecyclerView.LayoutManager layoutManager) {
 return findEndView(layoutManager, getHorizontalHelper(layoutManager));
 }

 /**
 * 找到第一个显示的view
 *
 * @param layoutManager
 * @param helper
 * @return
 */
 private View findEndView(RecyclerView.LayoutManager layoutManager, OrientationHelper helper) {
 if (layoutManager instanceof LinearLayoutManager) {
  int lastChild = ((LinearLayoutManager) layoutManager).findLastVisibleItemPosition();
  if (lastChild == RecyclerView.NO_POSITION) {
  return null;
  }

  View child = layoutManager.findViewByPosition(lastChild);

  //得到此时需要右对齐显示的条目
  if (helper.getDecoratedStart(child) >= helper.getDecoratedMeasurement(child) / 2
   && helper.getDecoratedStart(child) > 0) {
  return child;
  } else {
  return layoutManager.findViewByPosition(lastChild - 1);
  }
 }
 return super.findSnapView(layoutManager);
 }

 /**
 * 获取视图的方向
 *
 * @param layoutManager
 * @return
 */
 private OrientationHelper getHorizontalHelper(@NonNull RecyclerView.LayoutManager layoutManager) {
 if (mHorizontalHelper == null) {
  mHorizontalHelper = OrientationHelper.createHorizontalHelper(layoutManager);
 }
 return mHorizontalHelper;
 }
}

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

@Override
public void onBindViewHolder(RecyclerViewHolder holder, int position) {
 Glide.with(mContext).load(mList.get(position % mList.size())
  .getImageUrl()).placeholder(R.mipmap.ic_launcher)
  .into(holder.ivImage);
 holder.tvName.setText(mList.get(position % mList.size()).getName());
}

private int cnt = 2; //表示当前最右边显示的item的position
private boolean isSlidingByHand = false; //表示是否是手在滑动
private boolean isSlidingAuto = true; //表示是否自动滑动

timer.schedule(new TimerTask() {
 @Override
 public void run() {
  if (isSlidingAuto) {
  myHandler.sendEmptyMessage(CHANGE_ITEM);
  }
 }
 }, 1000, 3000);

alRecyclerview.addOnScrollListener(new RecyclerView.OnScrollListener() {
 @Override
 public void onScrollStateChanged(RecyclerView recyclerView, int newState) {
  LinearLayoutManager manager = (LinearLayoutManager) recyclerView.getLayoutManager();
  int firstVisibleItemPosition = manager.findFirstVisibleItemPosition();
  switch (newState) {
  case SCROLL_STATE_IDLE: //（静止没有滚动）
   if (isSlidingByHand) {
   Message msg = myHandler.obtainMessage();
   msg.arg1 = firstVisibleItemPosition;
   msg.what = CHANGE_ITEM;
   myHandler.sendMessage(msg);
   }
   break;
  case SCROLL_STATE_DRAGGING: //（正在被外部拖拽,一般为用户正在用手指滚动）
   isSlidingByHand = true;
   isSlidingAuto = false;
   break;
  case SCROLL_STATE_SETTLING: //（自动滚动）
   if (isSlidingByHand) {
   isSlidingAuto = false;
   } else {
   isSlidingAuto = true;
   }
   break;
  }
 }
 });

private static class MyHandler extends Handler {
 //采用弱引用的方式，防止内存泄漏
 WeakReference<CenterActivity> weakReference;

 public MyHandler(CenterActivity mActivity) {
 this.weakReference = new WeakReference<>(mActivity);
 }

 @Override
 public void handleMessage(Message msg) {
 final CenterActivity mActivity = weakReference.get();
 Log.d(TAG, "handleMessage: " + "handler is running");
 if (mActivity.isSlidingByHand) {
  mActivity.cnt = msg.arg1;
  mActivity.isSlidingByHand = false;
  mActivity.isSlidingAuto = true;
  mActivity.cnt+=2;
  //让RecyclerView平滑的滚动
  mActivity.alRecyclerview.smoothScrollToPosition(++mActivity.cnt);
 } else {
  mActivity.alRecyclerview.smoothScrollToPosition(++mActivity.cnt);
 }
 }
}