unity ugui list 代码封装

以下是使用Unity UGUI创建可滚动列表的封装代码：

using UnityEngine;
using UnityEngine.UI;
using System.Collections.Generic;

public class ScrollableList : MonoBehaviour
{
    public GameObject listItemPrefab;
    public Transform contentPanel;
    public ScrollRect scrollRect;

    private List<GameObject> listItems = new List<GameObject>();

    public void AddListItem(string text)
    {
        GameObject listItem = Instantiate(listItemPrefab) as GameObject;
        listItem.transform.SetParent(contentPanel, false);
        listItem.GetComponent<Text>().text = text;
        listItems.Add(listItem);

        UpdateContentSize();
    }

    public void RemoveListItem(int index)
    {
        if (index >= 0 && index < listItems.Count)
        {
            Destroy(listItems[index]);
            listItems.RemoveAt(index);

            UpdateContentSize();
        }
    }

    public void ClearList()
    {
        foreach (GameObject listItem in listItems)
        {
            Destroy(listItem);
        }

        listItems.Clear();

        UpdateContentSize();
    }

    private void UpdateContentSize()
    {
        GridLayoutGroup gridLayout = contentPanel.GetComponent<GridLayoutGroup>();
        float cellSize = gridLayout.cellSize.y + gridLayout.spacing.y;
        float spacing = gridLayout.padding.top + gridLayout.padding.bottom + gridLayout.spacing.y;
        int rowCount = Mathf.CeilToInt(listItems.Count / (float)gridLayout.constraintCount);
        float height = rowCount * cellSize + spacing;
        contentPanel.GetComponent<RectTransform>().sizeDelta = new Vector2(0, height);
    }
}

在这个封装代码中，我们将创建、添加、删除和清空列表项的功能封装成了公共函数。当添加、删除、或清空列表项时，我们都会调用`UpdateContentSize()`函数来重新计算内容面板的大小并设置为`contentPanel`的大小。这样，我们就可以在脚本中方便地使用这个可滚动列表了。