AndroidTV VerticalGridView倒数第二行下面为空时修改KEYCODE_DPAD_DOWN事件跳转逻辑

需求背景 : Android TV开发视频列表最后一行未满时，如果当前焦点在倒数第二行，下面为空，需要特殊处理将KEYCODE_DPAD_DOWN事件，移动焦点至最后一行

处理逻辑 : OnChildViewHolderSelectedListener监听中，记录位置，在setOnKeyListener中处理KEYCODE_DPAD_DOWN事件跳转逻辑。

具体逻辑参考如下代码 :

public class CustomVerticalGridView extends VerticalGridView {

    private int columns;
    private int itemCount;

    private static final String TAG = "CustomVerticalGridView";

    /**
     * 倒数第二行下方没有item的时候，
     * 按KEYCODE_DPAD_DOWN时，最后一行第一个item获取焦点
     */
    private final OnChildViewHolderSelectedListener mListener = new OnChildViewHolderSelectedListener() {
        @Override
        public void onChildViewHolderSelected(RecyclerView parent, ViewHolder child, int position, int subPosition) {
            super.onChildViewHolderSelected(parent, child, position, subPosition);
            itemCount = Objects.requireNonNull(getAdapter()).getItemCount();
            Log.d(TAG, "position=======" + position);
            Log.d(TAG, "itemCount======" + itemCount);
            int lastRowNumber = itemCount % columns;
            int rowNumber = itemCount / columns;
            //用于判断当前位置是倒数第二行，且下方Item为空
            if ((lastRowNumber > 0) && ((position + 1) <= (itemCount - lastRowNumber)) &&
                    ((position + 1) > (rowNumber * columns - (columns - lastRowNumber)))) {
                child.itemView.setOnKeyListener((v, keyCode, event) -> {
                    if (keyCode == KeyEvent.KEYCODE_DPAD_DOWN && event.getAction() == KeyEvent.ACTION_DOWN) {
                    //焦点移动至最后一行第一个
                    //此处逻辑可根据具体项目要求修改
                        scrollToPosition(rowNumber * columns);
                    }
                    return false;
                });
            }
        }
    };

    public CustomVerticalGridView(Context context) {
        super(context);
        setOnChildViewHolderSelectedListener(mListener);
    }

    public CustomVerticalGridView(Context context, AttributeSet attrs) {
        super(context, attrs);
        setOnChildViewHolderSelectedListener(mListener);
    }

    public CustomVerticalGridView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        setOnChildViewHolderSelectedListener(mListener);
    }

    @Override
    public void setNumColumns(int numColumns) {
        super.setNumColumns(numColumns);
        Log.i(TAG, "setNumColumns=====" + numColumns);
        columns = numColumns;
    }

}