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);
  }
  /// <summary>
  /// 
  /// </summary>
  /// <param name="recttransform"></param>
  /// <param name="pos">世界坐标的position</param>
  /// <returns></returns>
  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<int, dynamicrect> inoverlaps = new dictionary<int, dynamicrect>();
 
   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);
    }
   }
  }
 
  /// <summary>
  /// 通过动态格子获得动态渲染器
  /// </summary>
  /// <param name="rect"></param>
  /// <returns></returns>
  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;
  }
  /// <summary>
  /// 获得待渲染的渲染器
  /// </summary>
  /// <returns></returns>
  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
 {
  /// <summary>
  /// 本地坐标
  /// </summary>
  public vector3 localpos;
  /// <summary>
  /// 格子索引
  /// </summary>
  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。