Unity3d—做一个年月日选择器（Scroll Rect拖动效果优化）

Unity3d—做一个年月日选择器（Scroll Rect拖动效果优化）— 无限滚动 + 锁定元素...

效果图

用的是UGUI

我先说思路

通过判断元素的位置信息来改变Hierarchy的顺序实现无限滚动

改变位置的同时也要不断的调整Content的位置防止乱跳

元素锁定就是直接锁死的元素的移动范围当只有拖动大于一定程度时才会发生改变

然后是面板设置

整体结构是这样子的

需要注意的是Content需要的两个组件

Content的爸爸只需要一个脚本

大小改变曲线（大致就行）

颜色渐变曲线

最后是脚本

  1 using System;
  2 using System.Collections;
  3 using System.Collections.Generic;
  4 using UnityEngine;
  5 using UnityEngine.EventSystems;
  6 using UnityEngine.UI;
  7 
  8 public class DateControl : MonoBehaviour, IBeginDragHandler, IDragHandler, IEndDragHandler {
  9 
 10     public enum ItemType { _year, _month, _day }
 11 
 12     public ItemType _itemtype;
 13 
 14     RectTransform conentRect;
 15 
 16     RectTransform targetRec;
 17 
 18     Vector3 oldDragPos;
 19 
 20     Vector3 newDragPos;
 21 
 22     public AnimationCurve curve_scale;//改变大小曲线
 23     public AnimationCurve curve_color;//渐变效果曲线
 24 
 25 
 26     List<Text> textList = new List<Text>();
 27 
 28     Button testBtn;
 29 
 30     float 
 31         itemHeight,             //子项item的高
 32         contentParentHeight,    //Content爸爸的高
 33         itemNum,                //子项数量
 34         itemHeight_min,         //子项最小发生改变位置
 35         itemHeight_max,         //子项最大发生改变位置
 36         conentLimit,            //Conent纠正位置
 37         conentSpacing;          //子项间隔大小
 38 
 39     float deltaX, deltaY;
 40 
 41     [HideInInspector]
 42     public static int _year, _month, _day;
 43 
 44     [HideInInspector]
 45     int dateItemNum;
 46 
 47     Color itemColor_hig = new Color32(255, 255, 255, 255);
 48 
 49     void Awake() {
 50         conentRect = transform.FindChild("Content").GetComponent<RectTransform>();
 51         targetRec = transform.parent.FindChild("HighlightTarget").GetComponent<RectTransform>();
 52 
 53     }
 54 
 55     void OnEnable() {
 56         ItemList();
 57     }
 58 
 59     void Start() {
 60         switch (_itemtype) {
 61             case ItemType._year: InstantiateData(15, 2017); break;
 62             case ItemType._month: InstantiateData(12, 12); break;
 63             case ItemType._day: InstantiateData(31, 31); break;
 64         }
 65 
 66         itemNum = transform.FindChild("Content").childCount - 1;
 67 
 68         contentParentHeight = conentRect.parent.GetComponent<RectTransform>().sizeDelta.y;
 69 
 70         conentSpacing = conentRect.GetComponent<VerticalLayoutGroup>().spacing / 2;
 71 
 72         itemHeight = textList[0].rectTransform.sizeDelta.y + conentSpacing;
 73 
 74         if (itemNum % 2 == 0) conentLimit = (itemHeight + 5) / 2;
 75 
 76         else conentLimit = 0;
 77 
 78         conentRect.anchoredPosition = new Vector2(conentRect.anchoredPosition.x, conentLimit);
 79 
 80         deltaX = textList[0].GetComponent<RectTransform>().sizeDelta.x;
 81         deltaY = textList[0].GetComponent<RectTransform>().sizeDelta.y;
 82 
 83         Invoke("ItemList", 0.05f);
 84 
 85     }
 86 
 87     /// <summary>
 88     /// 生成子项item
 89     /// </summary>
 90     /// <param name="itemNum">子项数量</param>
 91     /// <param name="dat">子项最大值</param>
 92     void InstantiateData(int itemNum, int dat) {
 93         GameObject go;
 94         Text testObj = conentRect.FindChild("Text").GetComponent<Text>();
 95         for (int i = dat - itemNum + 1; i <= dat; i++) {
 96             go = Instantiate(testObj.gameObject, conentRect);
 97             go.GetComponent<Text>().text = i.ToString();
 98             go.name = i.ToString();
 99             textList.Add(go.GetComponent<Text>());
100             ShowItem(true);
101         }
102         Destroy(conentRect.FindChild("Text").gameObject);
103     }
104 
105     /// <summary>
106     /// 是增加或减少
107     /// </summary>
108     /// <param name="isIncreaseOrdecrease"></param>
109     void ShowItem(bool isIncreaseOrdecrease) {
110         itemHeight_min = -itemHeight;
111 
112         if (_itemtype == ItemType._day) itemHeight_max = -itemHeight * itemNum - 95;
113         else itemHeight_max = -itemHeight * itemNum;
114 
115         if (isIncreaseOrdecrease) {
116             foreach (Text rectItem in textList) {
117                 if (rectItem.GetComponent<RectTransform>().anchoredPosition.y > itemHeight_min) {
118                     print("+");
119                     rectItem.transform.SetSiblingIndex((int)itemNum);
120                 }
121             }
122             print(itemHeight_min);
123         } else {
124             foreach (Text rectItem in textList) {
125                 if (rectItem.GetComponent<RectTransform>().anchoredPosition.y < itemHeight_max) {
126                     print("-");
127                     rectItem.transform.SetSiblingIndex(0);
128                 }
129             }
130             print(itemHeight_max);
131 
132         }
133     }
134 
135     /// <summary>
136     /// 渐变效果，改变大小，高亮显示
137     /// </summary>
138     void ItemList() {
139         foreach (Text item in textList) {
140             float indexA = Mathf.Abs(item.GetComponent<RectTransform>().position.y - targetRec.position.y);
141             float indexSc_scale = Mathf.Abs(curve_scale.Evaluate(indexA / contentParentHeight));
142             float indexSc_color = Mathf.Abs(curve_color.Evaluate(indexA / contentParentHeight));
143             if (indexA < 15) {
144                 item.color = itemColor_hig;
145                 switch (_itemtype) {
146                     case ItemType._year: _year = int.Parse(item.text); break;
147                     case ItemType._month: _month = int.Parse(item.text); break;
148                     case ItemType._day: _day = int.Parse(item.text); break;
149                 }
150             } else item.color = new Color(0, 0, 0, 1 - indexSc_color);
151 
152             item.GetComponent<RectTransform>().localScale = new Vector3(1 - indexSc_scale, 1 - indexSc_scale * 3, 1 - indexSc_scale);
153             //item.GetComponent<RectTransform>().sizeDelta = new Vector2(deltaX - (deltaX * indexSc), deltaY - (deltaY * indexSc));
154         }
155 
156     }
157 
158     /// <summary>
159     /// 获取int类型日期，并转换为指定格式
160     /// </summary>
161     /// <returns></returns>
162     public static string GetDateInfo() { return _year + "-" + _month + "-" + _day; }
163 
164     /// <summary>
165     /// 纠正Conent位置
166     /// </summary>
167     void UpdateEx() {
168         if (conentRect.anchoredPosition.y > conentLimit) {
169             ShowItem(true);
170             conentRect.anchoredPosition = new Vector2(conentRect.anchoredPosition.x, conentRect.anchoredPosition.y - itemHeight);
171         }
172         if (conentRect.anchoredPosition.y < conentLimit) {
173             ShowItem(false);
174             conentRect.anchoredPosition = new Vector2(conentRect.anchoredPosition.x, conentRect.anchoredPosition.y + itemHeight);
175         }
176     }
177 
178     /// <summary>
179     /// 获取拖拽信息并改变Conent位置
180     /// </summary>
181     /// <param name="eventData"></param>
182     void SetDraggedPosition(PointerEventData eventData) {
183         if (RectTransformUtility.ScreenPointToWorldPointInRectangle(conentRect, eventData.position, eventData.pressEventCamera, out newDragPos)) {
184             newDragPos = eventData.position;
185             if (Mathf.Abs(newDragPos.y - oldDragPos.y) >= itemHeight) {
186                 if (newDragPos.y > oldDragPos.y) {
187                     conentRect.anchoredPosition = new Vector2(conentRect.anchoredPosition.x, conentRect.anchoredPosition.y + itemHeight);
188                     oldDragPos += new Vector3(0, itemHeight, 0);
189                     ItemList();
190                 } else {
191                     conentRect.anchoredPosition = new Vector2(conentRect.anchoredPosition.x, conentRect.anchoredPosition.y - itemHeight);
192                     oldDragPos -= new Vector3(0, itemHeight, 0);
193                     ItemList();
194                 }
195             }
196         }
197     }
198 
199     /// <summary>
200     /// 当开始拖拽
201     /// </summary>
202     /// <param name="eventData"></param>
203     public void OnBeginDrag(PointerEventData eventData) {
204         oldDragPos = eventData.position;
205     }
206 
207     public void OnDrag(PointerEventData eventData) {
208         SetDraggedPosition(eventData);
209         UpdateEx();
210     }
211 
212     public void OnEndDrag(PointerEventData eventData) {
213         SetDraggedPosition(eventData);
214         UpdateEx();
215     }
216 }