unity实现图片轮播效果_Unity3D实现列表拖拽轮播分页滚动功能
在使用UGUI的ScrollRect做列表滚动时，会有分页滚动的需求，基于ScrollRect写了一个，只需要一个ScrollRect组件即可
效果截图：
Threshold为滚动阈值，当翻页的长度达到总长度的0.2时即会翻页，speed为松开鼠标后的缓动速度
以下为代码：
using UnityEngine;
using UnityEngine.UI;
using UnityEngine.EventSystems;
using System.Collections;
public class RollScroll : MonoBehaviour, IBeginDragHandler, IEndDragHandler
{
//滚动条
public ScrollRect scrollRect;
//左右按钮
public Button leftButton, rightButton;
//滚动阈值
public float Threshold = 0.2f;
//缓动速度
public float speed = 10f;
//是否开启拖拽滚动
private bool IsStart = false;
//总个数
private int Number;
//当前进行到的个数
private int currentNumber;
private int CurrentNumber
{
get
{
return currentNumber;
}
set
{
currentNumber = value;
//更新按钮显示状态
ButtonUIUpdate();
}
}
/// /// 初始化轮播
///
/// 总页数
/// 初始页数
public void OnInitRollScroll(int _number, int _currentNumber)
{
if (_number <= 1) return;
//总个数
Number = _number;
//当前个数
CurrentNumber = _currentNumber;
//设置起点
StartCoroutine(HandlePosition(GetScrollPosition(CurrentNumber)));
//content = scrollRect.content;
//左按钮点击事件
leftButton.onClick.RemoveAllListeners();
leftButton.onClick.AddListener(OnLeft);
//右按钮点击事件
rightButton.onClick.RemoveAllListeners();
rightButton.onClick.AddListener(OnRight);
IsStart = true;
}
//延迟执行设置初始化滚动起点
private IEnumerator HandlePosition(float number)
{
yield return null;
yield return null;
scrollRect.horizontalNormalizedPosition = number;
}
#region 拖拽事件
public void OnBeginDrag(PointerEventData eventData)
{
if (!IsStart) return;
StopAllCoroutines();
}
public void OnEndDrag(PointerEventData eventData)
{
if (!IsStart) return;
//Debug.Log("结束拖拽");
//滚动前的position
float lastPosition = GetScrollPosition(currentNumber);
//滚动后的position
float currentPosition = scrollRect.horizontalNormalizedPosition;
if (currentPosition > lastPosition)
{
float n = 1f / (Number - 1);
float thre = currentPosition - lastPosition;
if (thre > n * Threshold)
{
OnRight();
}
else //还原
{
StopAllCoroutines();
StartCoroutine(LerpRoll(lastPosition));
}
}
else
{
float n = 1f / (Number - 1);
float thre = lastPosition - currentPosition;
if (thre > n * Threshold)
{
OnLeft();
}
else //还原
{
StopAllCoroutines();
StartCoroutine(LerpRoll(lastPosition));
}
}
}
#endregion
#region 左右按钮事件
//左按钮事件
private void OnLeft()
{
if (CurrentNumber > 0)
{
CurrentNumber--;
StopAllCoroutines();
StartCoroutine(LerpRoll(GetScrollPosition(CurrentNumber)));
}
}
//右按钮事件
private void OnRight()
{
if (CurrentNumber < Number - 1)
{
CurrentNumber++;
StopAllCoroutines();
StartCoroutine(LerpRoll(GetScrollPosition(CurrentNumber)));
}
}
#endregion
#region 功能方法
//缓动滚动到...
private IEnumerator LerpRoll(float position)
{
while (true)
{
if (Mathf.Abs(scrollRect.horizontalNormalizedPosition - position) <= 0.001f)
{
scrollRect.horizontalNormalizedPosition = position;
break;
}
else
{
scrollRect.horizontalNormalizedPosition = Mathf.Lerp(scrollRect.horizontalNormalizedPosition, position, Time.deltaTime * speed);
}
yield return null;
}
}
/// /// 获取滚动条value 0 - 1的值
///
private float GetScrollPosition(int number)
{
float n = 1f / (Number - 1);
float scrollPosition = Mathf.Clamp(n * number, 0, 1);
//Debug.Log(scrollPosition);
return scrollPosition;
}
//按钮更新显示状态
private void ButtonUIUpdate()
{
if (Number == 1)
{
leftButton.interactable = false;
rightButton.interactable = false;
return;
}
if (currentNumber == 0)
{
leftButton.interactable = false;
rightButton.interactable = true;
}
else if (currentNumber == Number - 1)
{
leftButton.interactable = true;
rightButton.interactable = false;
}
else
{
leftButton.interactable = true;
rightButton.interactable = true;
}
}
#endregion
}