在RecyclerView的Adapter中，可以通过重写onBindViewHolder方法来动态设置ViewHolder的视图大小。例如，在以下示例中，我们使用LinearLayoutManager和getItemCount()方法来实现从屏幕上方滑入的动画效果：

public class MyAdapter extends RecyclerView.Adapter {

    private List mData;
    private LinearLayoutManager mLayoutManager;

    public MyAdapter(List data, LinearLayoutManager layoutManager) {
        mData = data;
        mLayoutManager = layoutManager;
    }

    @Override
    public ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(parent.getContext())
                .inflate(R.layout.item_layout, parent, false);
        return new ViewHolder(view);
    }

    @Override
    public void onBindViewHolder(ViewHolder holder, int position) {
        holder.mTextView.setText(mData.get(position));
        // 获取屏幕高度
        int screenHeight = Resources.getSystem().getDisplayMetrics().heightPixels;
        // 设置ViewHolder视图大小为屏幕高度/3
        ViewGroup.LayoutParams params = holder.itemView.getLayoutParams();
        params.height = screenHeight / 3;
        holder.itemView.setLayoutParams(params);
        // 判断当前位置是否在屏幕上一半以上
        if (holder.getAdapterPosition() > mLayoutManager.getItemCount() / 2) {
            holder.itemView.setTranslationY(screenHeight / 3);
            holder.itemView.animate().translationY(0)
                    .setInterpolator(new DecelerateInterpolator(3.f))
                    .setDuration(700)
                    .start();
        }
    }

    @Override
    public int getItemCount() {
        return mData.size();
    }

    static class ViewHolder extends RecyclerView.ViewHolder {

        TextView mTextView;

        ViewHolder(View itemView) {
            super(itemView);
            mTextView = itemView.findViewById(R.id.item_text);
        }
    }
}