在Unity中除了用Slider、Image做进度条，其实用Scrollbar也可以做进度条。

首先，在场景中新建一个Scrollbar组件和一个Text组件：

其次，创建模拟进度的一个脚本，Scrollbar_Progressbar.cs:

using System.Collections;
using System.Collections.Generic;
using UnityEngine;
using UnityEngine.UI;
using TMPro;public class Scrollbar_Progressbar : MonoBehaviour
{public Scrollbar scrollbar;public TextMeshProUGUI text;private float curCount = 0;  //当前加载量,从0开始加载private float allCount = 100f;   //总加载量,这里设置为100private float smoothSpeed = 0.1f;  //加载的速度private bool changeValue;private bool changeSize;// Start is called before the first frame updatevoid Start(){}// Update is called once per framevoid Update(){if(Input.GetKeyDown(KeyCode.A)){changeValue = true;curCount = 0;scrollbar.size = 0;}else if(Input.GetKeyDown(KeyCode.S)){changeSize = true;curCount = 0;scrollbar.value = 0;            }if(changeValue){if (curCount < allCount){curCount += smoothSpeed;if (curCount > allCount){curCount = 100f;}scrollbar.value = curCount / 100f;text.text = (int)curCount / allCount * 100 + "%";}else{changeValue = false;}}if(changeSize){if (curCount < allCount){curCount += smoothSpeed;if (curCount > allCount){curCount = 100f;}scrollbar.size = curCount / 100f;text.text = (int)curCount / allCount * 100 + "%";}else{changeSize = false;}}}
}

我这里特别模拟了改变scrollbar中Value和Size属性的两种情况，经检验，只有改变Size值才符合进度条的效果。

具体效果如下：