public class LooperLayoutManager extends RecyclerView.LayoutManager {
    @Override
  public RecyclerView.LayoutParams generateDefaultLayoutParams() {
    return new RecyclerView.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT,
        ViewGroup.LayoutParams.WRAP_CONTENT);
  }
}

  @Override
  public boolean canScrollHorizontally() {
    return true;
  }

  @Override
  public void onLayoutChildren(RecyclerView.Recycler recycler, RecyclerView.State state) {
    if (getItemCount() <= 0) {
      return;
    }
    //標(biāo)注1.如果當(dāng)前時(shí)準(zhǔn)備狀態(tài)，直接返回
    if (state.isPreLayout()) {
      return;
    }
    //標(biāo)注2.將視圖分離放入scrap緩存中，以準(zhǔn)備重新對(duì)view進(jìn)行排版
    detachAndScrapAttachedViews(recycler);

    int autualWidth = 0;
    for (int i = 0; i < getItemCount(); i++) {
      //標(biāo)注3.初始化，將在屏幕內(nèi)的view填充
      View itemView = recycler.getViewForPosition(i);
      addView(itemView);
      //標(biāo)注4.測(cè)量itemView的寬高
      measureChildWithMargins(itemView, 0, 0);
      int width = getDecoratedMeasuredWidth(itemView);
      int height = getDecoratedMeasuredHeight(itemView);
      //標(biāo)注5.根據(jù)itemView的寬高進(jìn)行布局
      layoutDecorated(itemView, autualWidth, 0, autualWidth + width, height);

      autualWidth += width;
      //標(biāo)注6.如果當(dāng)前布局過的itemView的寬度總和大于RecyclerView的寬，則不再進(jìn)行布局
      if (autualWidth > getWidth()) {
        break;
      }
    }
  }

@Override
  public int scrollHorizontallyBy(int dx, RecyclerView.Recycler recycler, RecyclerView.State state) {
    //標(biāo)注1.橫向滑動(dòng)的時(shí)候，對(duì)左右兩邊按順序填充itemView
    int travl = fill(dx, recycler, state);
    if (travl == 0) {
      return 0;
    }

    //2.滑動(dòng)
    offsetChildrenHorizontal(-travl);

    //3.回收已經(jīng)不可見的itemView
    recyclerHideView(dx, recycler, state);
    return travl;
  }

  /**
   * 左右滑動(dòng)的時(shí)候，填充
   */
  private int fill(int dx, RecyclerView.Recycler recycler, RecyclerView.State state) {
    if (dx > 0) {
      //標(biāo)注1.向左滾動(dòng)
      View lastView = getChildAt(getChildCount() - 1);
      if (lastView == null) {
        return 0;
      }
      int lastPos = getPosition(lastView);
      //標(biāo)注2.可見的最后一個(gè)itemView完全滑進(jìn)來了，需要補(bǔ)充新的
      if (lastView.getRight() < getWidth()) {
        View scrap = null;
        //標(biāo)注3.判斷可見的最后一個(gè)itemView的索引，
        // 如果是最后一個(gè)，則將下一個(gè)itemView設(shè)置為第一個(gè)，否則設(shè)置為當(dāng)前索引的下一個(gè)
        if (lastPos == getItemCount() - 1) {
          if (looperEnable) {
            scrap = recycler.getViewForPosition(0);
          } else {
            dx = 0;
          }
        } else {
          scrap = recycler.getViewForPosition(lastPos + 1);
        }
        if (scrap == null) {
          return dx;
        }
        //標(biāo)注4.將新的itemViewadd進(jìn)來并對(duì)其測(cè)量和布局
        addView(scrap);
        measureChildWithMargins(scrap, 0, 0);
        int width = getDecoratedMeasuredWidth(scrap);
        int height = getDecoratedMeasuredHeight(scrap);
        layoutDecorated(scrap,lastView.getRight(), 0,
            lastView.getRight() + width, height);
        return dx;
      }
    } else {
      //向右滾動(dòng)
      View firstView = getChildAt(0);
      if (firstView == null) {
        return 0;
      }
      int firstPos = getPosition(firstView);

      if (firstView.getLeft() >= 0) {
        View scrap = null;
        if (firstPos == 0) {
          if (looperEnable) {
            scrap = recycler.getViewForPosition(getItemCount() - 1);
          } else {
            dx = 0;
          }
        } else {
          scrap = recycler.getViewForPosition(firstPos - 1);
        }
        if (scrap == null) {
          return 0;
        }
        addView(scrap, 0);
        measureChildWithMargins(scrap,0,0);
        int width = getDecoratedMeasuredWidth(scrap);
        int height = getDecoratedMeasuredHeight(scrap);
        layoutDecorated(scrap, firstView.getLeft() - width, 0,
            firstView.getLeft(), height);
      }
    }
    return dx;
  }

    //2.滾動(dòng)
    offsetChildrenHorizontal(travl * -1);

  /**
   * 回收界面不可見的view
   */
  private void recyclerHideView(int dx, RecyclerView.Recycler recycler, RecyclerView.State state) {
    for (int i = 0; i < getChildCount(); i++) {
      View view = getChildAt(i);
      if (view == null) {
        continue;
      }
      if (dx > 0) {
        //標(biāo)注1.向左滾動(dòng)，移除左邊不在內(nèi)容里的view
        if (view.getRight() < 0) {
          removeAndRecycleView(view, recycler);
          Log.d(TAG, "循環(huán): 移除 一個(gè)view childCount=" + getChildCount());
        }
      } else {
        //標(biāo)注2.向右滾動(dòng)，移除右邊不在內(nèi)容里的view
        if (view.getLeft() > getWidth()) {
          removeAndRecycleView(view, recycler);
          Log.d(TAG, "循環(huán): 移除 一個(gè)view childCount=" + getChildCount());
        }
      }
    }

  }

    recyclerView.setAdapter(new MyAdapter());
    LooperLayoutManager layoutManager = new LooperLayoutManager();
    layoutManager.setLooperEnable(true);
    recyclerView.setLayoutManager(layoutManager);