要实现一个简单的UI左右折叠显示与隐藏，可以结合遮罩，通过代码控制UI区块的宽度和位移来实现。

具体可以按以下步骤实现：

1、新建一个Image组件，并添加精灵，调整大小后，复制一份作为该UI的父物体，然后在该父物体上添加Mask组件，并勾掉Show Mask Graphic选项，如图：

2、新建两个控制按钮，如下图：

3、编写控制脚本：

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;public class SlideInOutUI : MonoBehaviour
{public RectTransform uiPanel;public Button showButton;public Button hideButton;public float slideSpeed = 5f;private bool isPanelShown = true;// Start is called before the first frame updatevoid Start(){showButton.onClick.AddListener(ShowPanel);hideButton.onClick.AddListener(HidePanel);}// Update is called once per framevoid Update(){Vector2 targetPosition = isPanelShown ? Vector2.zero : new Vector2(-uiPanel.rect.width, 0);uiPanel.anchoredPosition = Vector2.Lerp(uiPanel.anchoredPosition, targetPosition, Time.deltaTime * slideSpeed);}private void ShowPanel(){isPanelShown = true;}private void HidePanel(){isPanelShown = false;}
}

4、运行效果：