需求是，我们在一个text组件中像写网页那样写入链接，然后点击这个链接，就能访问配置的网页啥的。比如：
<a href="hello">链接文本</a></summary>最终的效果如下：
图中，image区域就是各个链接的点击范围。原理是获取text中，每个字符的位置，然后算出每个链接对应的点击区域，最后返回鼠标点到的那个区域的链接。代码比较简单，就直接写点注释看吧。实现是继承了text组件，当然写成静态方法传入text来计算也可以。
比较一下网上搜到的其他方案，这个方法不用重载mesh，效率应该是比较高的。
#define TEST_CheckClickURL
using System.Collections.Generic;
using System.Text.RegularExpressions;
using UnityEngine;
using UnityEngine.Profiling;
using UnityEngine.UI;public class TestClickURL : Text
{public Button button;public void OnButtonClick(){Debug.Log(CheckClickURL()?.url);}// 定义返回的结果public class CheckClickURLResult{public string url;public string text;public Rect rect;public CheckClickURLResult(string url, string text, Rect rect){this.url = url;this.text = text;this.rect = rect;}}private static Regex hrefRegex =new Regex(@"<a href=([^>\n\s]+)>(.*?)(</a>)",RegexOptions.Singleline);/// <summary> 计算点击到的URL文本内容，返回网址/// 格式如下：<a href="hello">链接文本</a></summary>public CheckClickURLResult CheckClickURL(){Profiler.BeginSample("CheckClickURL");if (hrefRegex == null)hrefRegex = new Regex(@"<a href=([^>\n\s]+)>(.*?)(</a>)", RegexOptions.Singleline);InitDebugGOList();// 将点击位置从屏幕坐标转为本地坐标RectTransformUtility.ScreenPointToLocalPointInRectangle(this.rectTransform, Input.mousePosition,null, out var mouseLocalPosition);//注意使用UI相机// 获取生成的文本数据。// characters 保存了每个字符左上角的位置。// lines 保存了每行开始字符ID，和行高。var generator = cachedTextGenerator;var charList = generator.characters;var lineList = generator.lines;var textStr = text;// 正则表达式查找链接文本var matchs = hrefRegex.Matches(textStr);foreach (Match match in matchs){var urlGroup = match.Groups[1];var textGroup = match.Groups[0];var textStartIndex = textGroup.Index;var textEndIndex = textGroup.Index + textGroup.Length;// 我们的字符可能是换行的，所以要按行分割。// 倒着遍历就很容易获取每行开始和结束位置。var lineEndIndex = charList.Count - 1;for (int i = lineList.Count - 1; i >= 0; i--){var lineStartIndex = lineList[i].startCharIdx;// 处理换行后的截取var realStart = Mathf.Max(lineStartIndex, textStartIndex);var realEnd = Mathf.Min(lineEndIndex, textEndIndex);// 本行没有链接内容的情况if (realStart > realEnd) continue;// 问题简化成单行的点击检查，提个函数继续处理。var result = CheckLine(realStart, realEnd, lineList[i].height, mouseLocalPosition, out var rect);if (result) return new CheckClickURLResult(urlGroup.Value, textGroup.Value, rect);//Debug.Log($"{start}/{end}");lineEndIndex = lineStartIndex - 1;}}Profiler.EndSample();return null;}public bool CheckLine(int start, int end, float lineHeight, Vector2 mouseLocalPosition, out Rect rect){// 获取生成的文本数据。var charList = cachedTextGenerator.characters;var startPoint = charList[start].cursorPos;var endPoint = charList[end].cursorPos;// 直接计算出本行中链接可点击区域。var x = startPoint.x;var y = startPoint.y - lineHeight;var width = endPoint.x - startPoint.x;var height = lineHeight;rect = new Rect(x, y, width, height);var result = rect.Contains(mouseLocalPosition);CreateDebugImage(rect, result);return result;}#if TEST_CheckClickURL// 测试用。生成空image展示出点击判定范围。public static List<GameObject> debugGOList;public void CreateDebugImage(Rect rect, bool contains){Debug.Log($"rect={rect}");var go = new GameObject("DebugImage",typeof(RectTransform), typeof(Image));debugGOList.Add(go);var rtf = go.GetComponent<RectTransform>();rtf.SetParent(transform);rtf.pivot = Vector2.zero;rtf.anchorMin = Vector2.one / 2;rtf.anchorMax = Vector2.one / 2;rtf.sizeDelta = rect.size;rtf.localScale = Vector3.one;rtf.rotation = Quaternion.identity;rtf.anchoredPosition = rect.position - rectTransform.rect.center;// 点击到的那个范围展示为红色。if (contains)go.GetComponent<Image>().color = Color.red;}public void InitDebugGOList(){if (debugGOList == null)debugGOList = new List<GameObject>();debugGOList.ForEach(p => Destroy(p));}
#elsepublic void CreateDebugImage(Rect rect, bool contains) { }public void InitDebugGOList() { }
#endif
}
