[UnityUI]NGUI性能优化之ScrollView
使用UIWrapContent优化ScrollView
![[UnityUI]NGUI性能优化之ScrollView_第1张图片](http://img.e-com-net.com/image/info8/faf93a73bf7c46fdb7355edf2f7b22a5.png)
如上图，虽然显示20个数据，但实际的GameObject只有6个，5个用于显示，1个用于缓存。NGUI中的UIWrapContent.cs通用性不是很好，需要修改一下：
//----------------------------------------------
// NGUI: Next-Gen UI kit
// Copyright © 2011-2015 Tasharen Entertainment
//----------------------------------------------
using UnityEngine;
using System.Collections.Generic;
///
/// This script makes it possible for a scroll view to wrap its content, creating endless scroll views.
/// Usage: simply attach this script underneath your scroll view where you would normally place a UIGrid:
///
/// + Scroll View
/// |- UIWrappedContent
/// |-- Item 1
/// |-- Item 2
/// |-- Item 3
///
[AddComponentMenu("NGUI/Interaction/Wrap Content")]
public class UIWrapContent : MonoBehaviour
{
public delegate void OnInitializeItem (GameObject go, int wrapIndex, int realIndex);
///
/// Width or height of the child items for positioning purposes.
///
public int itemSize = 100;
///
/// Whether the content will be automatically culled. Enabling this will improve performance in scroll views that contain a lot of items.
///
public bool cullContent = true;
///
/// Minimum allowed index for items. If "min" is equal to "max" then there is no limit.
/// For vertical scroll views indices increment with the Y position (towards top of the screen).
///
public int minIndex = 0;
///
/// Maximum allowed index for items. If "min" is equal to "max" then there is no limit.
/// For vertical scroll views indices increment with the Y position (towards top of the screen).
///
public int maxIndex = 0;
///
/// Callback that will be called every time an item needs to have its content updated.
/// The 'wrapIndex' is the index within the child list, and 'realIndex' is the index using position logic.
///
public OnInitializeItem onInitializeItem;
Transform mTrans;
UIPanel mPanel;
UIScrollView mScroll;
bool mHorizontal = false;
bool mFirstTime = true;
List mChildren = new List();
Vector3 mFirstPos;
///
/// Initialize everything and register a callback with the UIPanel to be notified when the clipping region moves.
///
protected virtual void Start ()
{
if (onInitializeItem == null) onInitializeItem = RefreshItem;
SortBasedOnScrollMovement();
WrapContent();
if (mScroll != null) mScroll.GetComponent().onClipMove = OnMove;
mFirstTime = false;
}
///
/// Callback triggered by the UIPanel when its clipping region moves (for example when it's being scrolled).
///
protected virtual void OnMove (UIPanel panel) { WrapContent(); }
///
/// Immediately reposition all children.
///
[ContextMenu("Sort Based on Scroll Movement")]
public void SortBasedOnScrollMovement ()
{
if (!CacheScrollView()) return;
// Cache all children and place them in order
mChildren.Clear();
for (int i = 0; i < mTrans.childCount; ++i)
mChildren.Add(mTrans.GetChild(i));
// Sort the list of children so that they are in order
if (mHorizontal) mChildren.Sort(UIGrid.SortHorizontal);
else mChildren.Sort(UIGrid.SortVertical);
ResetChildPositions();
}
///
/// Immediately reposition all children, sorting them alphabetically.
///
[ContextMenu("Sort Alphabetically")]
public void SortAlphabetically ()
{
if (!CacheScrollView()) return;
// Cache all children and place them in order
mChildren.Clear();
for (int i = 0; i < mTrans.childCount; ++i)
mChildren.Add(mTrans.GetChild(i));
// Sort the list of children so that they are in order
mChildren.Sort(UIGrid.SortByName);
ResetChildPositions();
}
///
/// Cache the scroll view and return 'false' if the scroll view is not found.
///
protected bool CacheScrollView ()
{
if (mTrans == null) mTrans = transform;
if (mPanel == null) mPanel = NGUITools.FindInParents(gameObject);
if (mScroll == null) mScroll = mPanel.GetComponent();
if (mScroll == null) return false;
if (mScroll.movement == UIScrollView.Movement.Horizontal) mHorizontal = true;
else if (mScroll.movement == UIScrollView.Movement.Vertical) mHorizontal = false;
else return false;
return true;
}
///
/// Helper function that resets the position of all the children.
///
void ResetChildPositions ()
{
mFirstPos = mChildren[0].localPosition;
for (int i = 0, imax = mChildren.Count; i < imax; ++i)
{
Transform t = mChildren[i];
t.localPosition = mHorizontal ? new Vector3(mFirstPos.x + i * itemSize, mFirstPos.y, 0f) : new Vector3(mFirstPos.x, mFirstPos.y - i * itemSize, 0f);
UpdateItem(t, i);
}
}
///
/// Wrap all content, repositioning all children as needed.
///
public void WrapContent ()
{
float extents = itemSize * mChildren.Count * 0.5f;
Vector3[] corners = mPanel.worldCorners;
for (int i = 0; i < 4; ++i)
{
Vector3 v = corners[i];
v = mTrans.InverseTransformPoint(v);
corners[i] = v;
}
Vector3 center = Vector3.Lerp(corners[0], corners[2], 0.5f);
bool allWithinRange = true;
float ext2 = extents * 2f;
if (mHorizontal)
{
float min = corners[0].x - itemSize;
float max = corners[2].x + itemSize;
for (int i = 0, imax = mChildren.Count; i < imax; ++i)
{
Transform t = mChildren[i];
float distance = t.localPosition.x - center.x;
if (distance < -extents)
{
Vector3 pos = t.localPosition;
pos.x += ext2;
distance = pos.x - center.x;
//int realIndex = Mathf.RoundToInt(pos.x / itemSize);
int realIndex = Mathf.RoundToInt((pos.x - mFirstPos.x) / itemSize);
if (minIndex == maxIndex || (minIndex <= realIndex && realIndex <= maxIndex))
{
t.localPosition = pos;
UpdateItem(t, i);
}
else allWithinRange = false;
}
else if (distance > extents)
{
Vector3 pos = t.localPosition;
pos.x -= ext2;
distance = pos.x - center.x;
//int realIndex = Mathf.RoundToInt(pos.x / itemSize);
int realIndex = Mathf.RoundToInt((pos.x - mFirstPos.x) / itemSize);
if (minIndex == maxIndex || (minIndex <= realIndex && realIndex <= maxIndex))
{
t.localPosition = pos;
UpdateItem(t, i);
}
else allWithinRange = false;
}
else if (mFirstTime) UpdateItem(t, i);
if (cullContent)
{
distance += mPanel.clipOffset.x - mTrans.localPosition.x;
if (!UICamera.IsPressed(t.gameObject))
NGUITools.SetActive(t.gameObject, (distance > min && distance < max), false);
}
}
}
else
{
float min = corners[0].y - itemSize;
float max = corners[2].y + itemSize;
for (int i = 0, imax = mChildren.Count; i < imax; ++i)
{
Transform t = mChildren[i];
float distance = t.localPosition.y - center.y;
if (distance < -extents)
{
Vector3 pos = t.localPosition;
pos.y += ext2;
distance = pos.y - center.y;
//int realIndex = Mathf.RoundToInt(pos.y / itemSize);
int realIndex = Mathf.RoundToInt((mFirstPos.y - pos.y) / itemSize);
if (minIndex == maxIndex || (minIndex <= realIndex && realIndex <= maxIndex))
{
t.localPosition = pos;
UpdateItem(t, i);
}
else allWithinRange = false;
}
else if (distance > extents)
{
Vector3 pos = t.localPosition;
pos.y -= ext2;
distance = pos.y - center.y;
//int realIndex = Mathf.RoundToInt(pos.y / itemSize);
int realIndex = Mathf.RoundToInt((mFirstPos.y - pos.y) / itemSize);
if (minIndex == maxIndex || (minIndex <= realIndex && realIndex <= maxIndex))
{
t.localPosition = pos;
UpdateItem(t, i);
}
else allWithinRange = false;
}
else if (mFirstTime) UpdateItem(t, i);
if (cullContent)
{
distance += mPanel.clipOffset.y - mTrans.localPosition.y;
if (!UICamera.IsPressed(t.gameObject))
NGUITools.SetActive(t.gameObject, (distance > min && distance < max), false);
}
}
}
mScroll.restrictWithinPanel = !allWithinRange;
}
///
/// Sanity checks.
///
void OnValidate ()
{
if (maxIndex < minIndex)
maxIndex = minIndex;
if (minIndex > maxIndex)
maxIndex = minIndex;
}
///
/// Want to update the content of items as they are scrolled? Override this function.
///
protected virtual void UpdateItem (Transform item, int index)
{
if (onInitializeItem != null)
{
int realIndex = (mScroll.movement == UIScrollView.Movement.Vertical) ?
Mathf.RoundToInt((mFirstPos.y - item.localPosition.y) / itemSize) :
Mathf.RoundToInt((item.localPosition.x - mFirstPos.x) / itemSize);
onInitializeItem(item.gameObject, index, realIndex);
}
}
protected virtual void RefreshItem(GameObject go, int wrapIndex, int realIndex)
{
}
}
使用起来也很简单：
using UnityEngine;
using System.Collections;
public class MyUIWrapContent : UIWrapContent {
protected override void RefreshItem(GameObject go, int wrapIndex, int realIndex)
{
go.transform.FindChild("Label").GetComponent().text = realIndex.ToString();
//Debug.Log(go.name + " " + wrapIndex + " " + realIndex);
}
}