UGUI轮播图组件实现方法详解

本文实例为大家分享了ugui轮播图组件实现的具体代码，供大家参考，具体内容如下

要用到，于是就自已做了一个，自认为封装上还是ok的，开发于unity5.1.2。

支持自动轮播、手势切换、代码调用切换，支持水平和竖直两个方向以及正负方向轮播，轮播索引改变有回调可以用，也可以获取到当前处于正中的子元素。

要注意的是，向轮播列表中加入新元素不能直接setparent，要调用该组件的addchild方法

下面是鄙人的代码：

/// 主要关注属性、事件及函数：
///  public int currentindex;
///  public action<int> onindexchange;
///  public virtual void movetoindex(int ind);
///  public virtual void addchild(recttransform t);
/// by yangxun
using unityengine;
using system.collections;
using system.collections.generic;
using unityengine.ui;
using unityengine.eventsystems;
using system;
/// <summary>
/// 轮播图组件
/// </summary>
[requirecomponent(typeof(recttransform)), executeineditmode]
public class carousel : uibehaviour, ieventsystemhandler, ibegindraghandler, iinitializepotentialdraghandler, idraghandler, ienddraghandler, icanvaselement {
 
 /// <summary>
 /// 子物体size
 /// </summary>
 public vector2 cellsize;
 /// <summary>
 /// 子物体间隔
 /// </summary>
 public vector2 spacing;
 /// <summary>
 /// 方向
 /// </summary>
 public axis moveaxis;
 /// <summary>
 /// tween时的步数
 /// </summary>
 public int tweenstepcount = 10;
 /// <summary>
 /// 自动轮播
 /// </summary>
 public bool autoloop = false;
 /// <summary>
 /// 轮播间隔
 /// </summary>
 public float loopspace = 1;
 /// <summary>
 /// 轮播方向--1为向左移动，-1为向右移动
 /// </summary>
 public int loopdir = 1;
 /// <summary>
 /// 可否拖动
 /// </summary>
 public bool drag = true;
 /// <summary>
 /// 位于正中的子元素变化的事件,参数为index
 /// </summary>
 public action<int> onindexchange;
 /// <summary>
 /// 当前处于正中的元素
 /// </summary>
 public int currentindex {
  get {
   return m_index;
  }
 }
 
 private bool m_dragging = false;
 private bool m_isnormalizing = false;
 private vector2 m_currentpos;
 private int m_currentstep = 0;
 private recttransform viewrecttran;
 private vector2 m_prepos;
 private int m_index = 0,m_preindex = 0;
 private recttransform header;
 private bool contentcheckcache = true;
 
 private float currtimedelta = 0;
 private float viewrectxmin {
  get{
   vector3[] v = new vector3[4];
   viewrecttran.getworldcorners(v);
   return v[0].x;
  }
 }
 private float viewrectxmax {
  get {
   vector3[] v = new vector3[4];
   viewrecttran.getworldcorners(v);
   return v[3].x;
  }
 }
 private float viewrectymin {
  get {
   vector3[] v = new vector3[4];
   viewrecttran.getworldcorners(v);
   return v[0].y;
  }
 }
 private float viewrectymax {
  get {
   vector3[] v = new vector3[4];
   viewrecttran.getworldcorners(v);
   return v[2].y;
  }
 }
 
 public int cellcount {
  get {
   return transform.childcount;
  }
 }
 protected override void awake() {
  base.awake();
  viewrecttran = getcomponent<recttransform>();
  header = getchild(viewrecttran, 0);
 }
 public void resizechildren() {
  //init child size and pos
  vector2 delta;
  if (moveaxis == axis.horizontal) {
   delta = new vector2(cellsize.x + spacing.x, 0);
  }
  else {
   delta = new vector2(0, cellsize.y + spacing.y);
  }
  for (int i = 0; i < cellcount; i++) {
   var t = getchild(viewrecttran, i);
   if (t) {
    t.localposition = delta * i;
    t.sizedelta = cellsize;
   }
  }
  m_isnormalizing = false;
  m_currentpos = vector2.zero;
  m_currentstep = 0;
 }
 /// <summary>
 /// 加子物体到当前列表的最后面
 /// </summary>
 /// <param name="t"></param>
 public virtual void addchild(recttransform t) {
  if (t!=null) {
   t.setparent(viewrecttran, false);
   t.setaslastsibling();
   vector2 delta;
   if (moveaxis == axis.horizontal) {
    delta = new vector2(cellsize.x + spacing.x, 0);
   }
   else {
    delta = new vector2(0, cellsize.y + spacing.y);
   }
   if (cellcount == 0) {
    t.localposition = vector3.zero;
    header = t;
   }
   else {
    t.localposition = delta + (vector2)getchild(viewrecttran,cellcount-1).localposition;
   }
  }
 }
 protected override void onenable() {
  base.onenable();
  resizechildren();
  return;
  if (application.isplaying) {
   if (contentislongerthanrect()) {
    int s;
    do {
     s = getboundarystate();
     loopcell(s);
    } while (s != 0);
   }
  }
 }
 protected virtual void update() {
  if (contentislongerthanrect()) {
   //实现在必要时loop子元素
   if (application.isplaying) {
    int s = getboundarystate();
    loopcell(s);
   }
   //缓动回指定位置
   if (m_isnormalizing && ensurelistcanadjust()) {
    if (m_currentstep == tweenstepcount) {
     m_isnormalizing = false;
     m_currentstep = 0;
     m_currentpos = vector2.zero;
     return;
    }
    vector2 delta = m_currentpos/tweenstepcount;
    m_currentstep++;
    tweentocorrect(-delta);
   }
   //自动loop
   if (autoloop && !m_isnormalizing && ensurelistcanadjust()) {
    currtimedelta += time.deltatime;
    if (currtimedelta>loopspace) {
     currtimedelta = 0;
     movetoindex(m_index + loopdir);
    }
   }
   //检测index是否变化
   if (moveaxis == axis.horizontal) {
    m_index = (int)(header.localposition.x / (cellsize.x + spacing.x-1));
   }
   else {
    m_index = (int)(header.localposition.y / (cellsize.y + spacing.y-1));
   }
   if (m_index<=0) {
    m_index = mathf.abs(m_index);
   }
   else {
    m_index = cellcount - m_index;
   }
   if (m_index != m_preindex) {
    if (onindexchange != null) {
     onindexchange(m_index);
    }
   }
   m_preindex = m_index;
  }
 }
 public virtual void onbegindrag(pointereventdata eventdata) {
  if (!drag || !contentcheckcache) {
   return;
  }
  vector2 vector;
  if (((eventdata.button == pointereventdata.inputbutton.left) && this.isactive()) && recttransformutility.screenpointtolocalpointinrectangle(this.viewrecttran, eventdata.position, eventdata.presseventcamera, out vector)) {
   this.m_dragging = true;
   m_prepos = vector;
  }
 }
 
 public virtual void oninitializepotentialdrag(pointereventdata eventdata) {
  if (!drag) {
   return;
  }
  return;
 }
 
 public virtual void ondrag(pointereventdata eventdata) {
  if (!drag || !contentcheckcache) {
   return;
  }
  vector2 vector;
  if (((eventdata.button == pointereventdata.inputbutton.left) && this.isactive()) && recttransformutility.screenpointtolocalpointinrectangle(this.viewrecttran, eventdata.position, eventdata.presseventcamera, out vector)) {
   m_isnormalizing = false;
   m_currentpos = vector2.zero;
   m_currentstep = 0;
   vector2 vector2 = vector - this.m_prepos;
   vector2 vec = calculateoffset(vector2);
   this.setcontentposition(vec);
   m_prepos = vector;
  }
 }
 /// <summary>
 /// 移动到指定索引
 /// </summary>
 /// <param name="ind"></param>
 public virtual void movetoindex(int ind) {
  if (m_isnormalizing) {
   return;
  }
  //debug.logformat("{0}->{1}",m_index,ind);
  if (ind == m_index) {
   return;
  }
  this.m_isnormalizing = true;
  vector2 offset;
  if (moveaxis == axis.horizontal) {
   offset = new vector2(cellsize.x + spacing.x, 0);
  }
  else {
   offset = new vector2(0, cellsize.y + spacing.y);
  }
  var delta = calccorrectdeltapos();
  int vindex = m_index;
  m_currentpos = delta + offset * (ind - vindex);
  //m_currentpos = -(vector2)header.localposition + offset * (ind - m_index);
  m_currentstep = 0;
 }
 private vector2 calculateoffset(vector2 delta) {
  if (moveaxis == axis.horizontal) {
   delta.y = 0;
  }
  else {
   delta.x = 0;
  }
  return delta;
 }
 private void setcontentposition(vector2 position) {
  foreach (recttransform i in viewrecttran) {
   i.localposition += (vector3)position;
  }
  return;
 }
 
 public virtual void onenddrag(pointereventdata eventdata) {
  if (!drag || !contentcheckcache) {
   return;
  }
  this.m_dragging = false;
  this.m_isnormalizing = true;
  m_currentpos = calccorrectdeltapos();
  m_currentstep = 0;
 }
 
 public virtual void rebuild(canvasupdate executing) {
  return;
 }
 /// <summary>
 /// list是否处于可*调整状态
 /// </summary>
 /// <returns></returns>
 public virtual bool ensurelistcanadjust() {
  return !m_dragging && contentislongerthanrect();
 }
 /// <summary>
 /// 内容是否比显示范围大
 /// </summary>
 /// <returns></returns>
 public virtual bool contentislongerthanrect() {
  float contentlen;
  float rectlen;
  if (moveaxis == axis.horizontal) {
   contentlen = cellcount*(cellsize.x + spacing.x) - spacing.x;
   rectlen = viewrecttran.rect.xmax - viewrecttran.rect.xmin;
  }
  else {
   contentlen = cellcount * (cellsize.y + spacing.y) - spacing.y;
   rectlen = viewrecttran.rect.ymax - viewrecttran.rect.ymin;
  }
  contentcheckcache = contentlen > rectlen;
  return contentcheckcache;
 }
 /// <summary>
 /// 检测边界情况，分为0未触界，-1左(下)触界，1右(上)触界
 /// </summary>
 /// <returns></returns>
 public virtual int getboundarystate() {
  recttransform left;
  recttransform right;
  left = getchild(viewrecttran, 0);
  right = getchild(viewrecttran, cellcount - 1);
  vector3[] l = new vector3[4];
  left.getworldcorners(l);
  vector3[] r = new vector3[4];
  right.getworldcorners(r);
  if (moveaxis == axis.horizontal) {
   if (l[0].x>=viewrectxmin) {
    return -1;
   }
   else if (r[3].x < viewrectxmax) {
    return 1;
   }
  }
  else {
   if (l[0].y >= viewrectymin) {
    return -1;
   }
   else if (r[1].y < viewrectymax) {
    return 1;
   }
  }
  return 0;
 }
 /// <summary>
 /// loop列表，分为-1把最右(上)边一个移到最左(下)边，1把最左(下)边一个移到最右(上)边
 /// </summary>
 /// <param name="dir"></param>
 protected virtual void loopcell(int dir) {
  if (dir == 0) {
   return;
  }
  recttransform movecell;
  recttransform tarborder;
  vector2 tarpos;
  if (dir == 1) {
   movecell = getchild(viewrecttran, 0);
   tarborder = getchild(viewrecttran, cellcount - 1);
   movecell.setsiblingindex(cellcount-1);
  }
  else {
   tarborder = getchild(viewrecttran, 0);
   movecell = getchild(viewrecttran, cellcount - 1);
   movecell.setsiblingindex(0);
  }
  if (moveaxis == axis.horizontal) {
   tarpos = tarborder.localposition + new vector3((cellsize.x + spacing.x) * dir, 0,0);
  }
  else {
   tarpos = (vector2)tarborder.localposition + new vector2(0, (cellsize.y + spacing.y) * dir);
  }
  movecell.localposition = tarpos;
 }
 /// <summary>
 /// 计算一个最近的正确位置
 /// </summary>
 /// <returns></returns>
 public virtual vector2 calccorrectdeltapos() {
  vector2 delta = vector2.zero;
  float distance = float.maxvalue;
  foreach (recttransform i in viewrecttran) {
   var td = mathf.abs(i.localposition.x) + mathf.abs(i.localposition.y);
   if (td<=distance) {
    distance = td;
    delta = i.localposition;
   }
   else {
    break;
   }
  }
  return delta;
 }
 /// <summary>
 /// 移动指定增量
 /// </summary>
 protected virtual void tweentocorrect(vector2 delta) {
  foreach (recttransform i in viewrecttran) {
   i.localposition += (vector3)delta;
  }
 }
 public enum axis {
  horizontal,
  vertical
 }
 private static recttransform getchild(recttransform parent, int index) {
  if (parent == null||index>=parent.childcount) {
   return null;
  }
  return parent.getchild(index) as recttransform;
 }
}

用法和ugui的scrollrect组件是差不多的，因为本来在drag事件上有所借鉴
例图如下：

另外，它不会像ugui的几个布局组件一样自动去改变子元素的大小为cellsize，cellsize只是虚拟的子元素容器大小，这个要注意下。

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。