95 lines
3.0 KiB
Dart
95 lines
3.0 KiB
Dart
import 'dart:ui';
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import 'package:flutter/cupertino.dart';
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import 'package:flutter/material.dart';
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richText({required String txt, required String key, Color highlight = Colors.red, Color defaultColor = Colors.black}) {
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assert(txt != null);
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assert(key != null);
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if (txt.contains(key)) {
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// 采用正则表达式环视保留分割的文本
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// 目前只考虑命中一次的情况简单分割
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// List<String> sps = txt.trim().split('$key'); //new RegExp('[?=$key]')
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// 使用最新的算法来计算
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List<String> sps = splitStr(txt, key);
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if (sps.length > 0) {
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List<TextSpan> textSpanList = [];
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for (String sp in sps) {
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print(sp);
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textSpanList.add(TextSpan(text: sp, style: TextStyle(color: sp == key ? highlight : defaultColor)));
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}
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return Text.rich(TextSpan(children: textSpanList));
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}
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}
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return Text(txt, style: TextStyle(color: defaultColor),);
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}
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List<String> splitStr(String txt, String key) {
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int keyLength = key.length;
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int index = txt.indexOf(key);
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// 因为要replace，所以使用备份的字符串
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String bakTxt = txt;
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if (index > -1) {
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List<int> indexes = [];
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indexes.add(index);
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int count = 0;
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while (index > -1) {
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bakTxt = bakTxt.replaceFirst('$key', '');
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int localIndex = bakTxt.indexOf(key);
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if (localIndex > -1) {
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count += 1;
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indexes.add(localIndex + keyLength * count);
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index = localIndex + keyLength * count;
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} else {
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index = localIndex;
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}
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}
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print('所有的索引：${indexes.toString()}');
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List<String> results = [];
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// 对上一步算出的所有索引进行迭代，导出分割后的数组
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int indexArrayIndex = 0;
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while (indexArrayIndex < indexes.length) {
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// 从左往后迭代。
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if (indexArrayIndex == 0) {
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if (indexes[indexArrayIndex] == 0) {
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results.add(txt.substring(0, keyLength));
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} else {
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results.add(txt.substring(0, indexes[indexArrayIndex]));
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results.add(txt.substring(indexes[indexArrayIndex], indexes[indexArrayIndex] + keyLength));
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}
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} else {
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results.add(txt.substring(indexes[indexArrayIndex], indexes[indexArrayIndex] + keyLength));
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}
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int endIndex = indexes[indexArrayIndex] + keyLength;
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// 如果还有索引，这一次只能算到下一个索引前
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if (indexArrayIndex < indexes.length - 1) {
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if (endIndex < indexes[indexArrayIndex + 1]) {
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results.add(txt.substring(endIndex, indexes[indexArrayIndex + 1]));
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} else {
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// 刚好是下一个自己，等下一次循环再说
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}
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} else {
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//只有一个索引的情况
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if (endIndex < txt.length) {
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results.add(txt.substring(endIndex, txt.length));
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} else {
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//结束了
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}
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}
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indexArrayIndex += 1;
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}
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print('迭代的结果：$results');
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return results;
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}
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return [];
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}
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