获取同级节点

/// <summary>
/// 获取同级的下一个节点
/// </summary>
/// <param name="node">当前节点</param>
/// <returns>下一个节点</returns>
public static Node GetNextSibling(Node node) {
    Node parent = node.GetParent();
    int index = node.GetIndex();
    return index < parent.GetChildCount() - 1 ? parent.GetChild(index + 1) : null;
}

/// <summary>
/// 获取同级的前一个节点
/// </summary>
/// <param name="node">当前节点</param>
/// <returns>前一个节点</returns>
public static Node GetLastSibling(Node node) {
	int index = node.GetIndex();
	return index != 0 ? node.GetParent().GetChild(index - 1) : null;
}