unity实现无限列表功能

本文实例为大家分享了unity实现无限列表功能的具体代码,供大家参考,具体内容如下

public static class RectTransformExtensions
  {
    public static bool Overlaps(this RectTransform a, RectTransform b)
    {
      return a.WorldRect().Overlaps(b.WorldRect());
    }
    public static bool Overlaps(this RectTransform a, RectTransform b, bool allowInverse)
    {
      return a.WorldRect().Overlaps(b.WorldRect(), allowInverse);
    }
 
    public static Rect WorldRect(this RectTransform rectTransform)
    {
      Vector2 sizeDelta = rectTransform.sizeDelta;
      float rectTransformWidth = sizeDelta.x * rectTransform.lossyScale.x;
      float rectTransformHeight = sizeDelta.y * rectTransform.lossyScale.y;
 
      Vector3 position = rectTransform.position;
 
      return new Rect(
        position.x - rectTransformWidth * rectTransform.pivot.x,
        position.y - rectTransformHeight * rectTransform.pivot.y,
        rectTransformWidth,
        rectTransformHeight);
    }
    /// 
    /// 
    /// 
    /// 
    /// 世界坐标的position
    /// 
    public static Rect WorldRect2(this RectTransform rectTransform, Vector3 pos)
    {
      Rect rect = new Rect();
      Vector2 sizeDelta = rectTransform.sizeDelta;
      float rectTransformWidth = sizeDelta.x * rectTransform.lossyScale.x;
      float rectTransformHeight = sizeDelta.y * rectTransform.lossyScale.y;
 
      Vector3 position = pos;
 
      rect.x = position.x - rectTransformWidth * rectTransform.pivot.x;
      rect.y = position.y - rectTransformHeight * rectTransform.pivot.y;
      rect.width = rectTransformWidth;
      rect.height = rectTransformHeight;
 
      return rect;
    }
  }

以上拓展方法是判断两个Recttransform类型的物体是否相交。

然后ScrollRec的滑动回调方法中更新UI位置,代码如下

private void OnScrollRectValueChanged(Vector2 arg0)
    {
      Dictionary inOverlaps = new Dictionary();
 
      mRectMask = 遮罩物体的RectTransform.WorldRect();
      //m_DynamicRectDic这个字典保存的是你所有UI需要放置的位置数据,
      //判断所有UI哪个是可见哪个不可见 ,保存起来
      foreach (DynamicRect dR in m_DynamicRectDic.Values)
      {
        tmpTra.localPosition = dR.localPos;
        //获取每个位置UI的世界坐标Rect
        Rect rect = m_LevelItemPrefabRT.WorldRect2(tmpTra.position);
        if (rect.Overlaps(mRectMask))
        {
          inOverlaps.Add(dR.Index, dR);
        }
      }
      //m_LevelItemList是保存你实例化后的UI列表,比如你这个遮罩页面最多显示3个UI,你需要实例化4个UI,然后动态修改gameobject的显示与隐藏
      int len = m_LevelItemList.Count;
      for (int i = 0; i < len; ++i)
      {
        //LevelItem是UI上挂载的脚本,用于更新UI界面的显示和数据存储的
        LevelItem item = m_LevelItemList[i];
        if (item.DRect != null && !inOverlaps.ContainsKey(item.DRect.Index))
        {
          //item的DRect为null时,隐藏物体,否则显示物体
          item.DRect = null;
        }
      }
      //判断哪些可以重复利用的UI,然后赋予新的数据与位置
      foreach (DynamicRect dR in inOverlaps.Values)
      {
        if (GetDynmicItem(dR) == null)
        {
          LevelItem item = GetNullDynmicItem();
 
          if (item == null) continue;
 
          item.DRect = dR;
          //更新UI的位置和显示(自己计算,每种显示不一样)
          _UpdateChildTransformPos(item.gameObject, dR.Index);
        }
      }
    }
 
    /// 
    /// 通过动态格子获得动态渲染器
    /// 
    /// 
    /// 
    private LevelItem GetDynmicItem(DynamicRect rect)
    {
      int len = m_LevelItemList.Count;
      for (int i = 0; i < len; ++i)
      {
        LevelItem item = m_LevelItemList[i];
        if (item.DRect == null)
          continue;
        if (rect.Index == item.DRect.Index)
          return item;
      }
      return null;
    }
    /// 
    /// 获得待渲染的渲染器
    /// 
    /// 
    private LevelItem GetNullDynmicItem()
    {
      int len = m_LevelItemList.Count;
      for (int i = 0; i < len; ++i)
      {
        LevelItem item = m_LevelItemList[i];
        if (item.DRect == null)
          return item;
      }
 
      return null;
    }
 
  public class DynamicRect
  {
    /// 
    /// 本地坐标
    /// 
    public Vector3 localPos;
    /// 
    /// 格子索引
    /// 
    public int Index;
 
    public DynamicRect(int index, Vector3 localPos)
    {
      this.Index = index;
      this.localPos = localPos;
    }
  }

以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持脚本之家。

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