由于正常recycleview注册context menu 后在 onContextItemSelected 里获取的 item.getMenuInfo() 为空， 不能正常使用长按menu，因此需要改造一下recycleview即可, 具体如下：

public class ContextMenuRecycleView extends RecyclerView {
    private AdapterView.AdapterContextMenuInfo contextMenuInfo;
    public ContextMenuRecycleView(Context context) {
        super(context);
    }
    public ContextMenuRecycleView(Context context, @Nullable AttributeSet attrs) {
        super(context, attrs);
    }
    public ContextMenuRecycleView(Context context, @Nullable AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }
    @Override
    public AdapterView.AdapterContextMenuInfo getContextMenuInfo() {
        return contextMenuInfo;
    }
    @Override
    public boolean showContextMenuForChild(View originalView) {
        int position = getChildAdapterPosition(originalView);
        long id = getChildItemId(originalView);
        contextMenuInfo = new AdapterView.AdapterContextMenuInfo(originalView, position, id);
        return super.showContextMenuForChild(originalView);
    }
}
具体原文参考 为RecycleView添加ContextMenu支持 - 爱码网 (likecs.com)