findWord method

void findWord(String word, { TextStyle? highlightStyle, bool matchCase = false, bool matchWholeWord = false, })

Search the document for occurrences of word and add highlight ranges.

• word: The substring to search for. If empty, existing highlights are cleared and listeners are notified.
• highlightStyle: Optional style applied to each found match. If null, a default amber background style is used.
• matchCase: When true the search is case-sensitive; otherwise the search is performed case-insensitively.
• matchWholeWord: When true matches are considered valid only when the matched substring is not adjacent to other word characters (letters, digits, or underscore).

Behavior: Clears existing searchHighlights, scans the document for matches according to the provided options, appends a SearchHighlight for each match, sets searchHighlightsChanged = true and calls notifyListeners() to request a repaint/update.

Implementation

void findWord(
  String word, {
  TextStyle? highlightStyle,
  bool matchCase = false,
  bool matchWholeWord = false,
}) {
  final style =
      highlightStyle ?? const TextStyle(backgroundColor: Colors.amberAccent);

  searchHighlights.clear();

  if (word.isEmpty) {
    searchHighlightsChanged = true;
    notifyListeners();
    return;
  }

  final searchText = text;
  final searchWord = matchCase ? word : word.toLowerCase();
  final textToSearch = matchCase ? searchText : searchText.toLowerCase();

  int offset = 0;
  while (offset < textToSearch.length) {
    final index = textToSearch.indexOf(searchWord, offset);
    if (index == -1) break;

    bool isMatch = true;

    if (matchWholeWord) {
      final before = index > 0 ? searchText[index - 1] : '';
      final after = index + word.length < searchText.length
          ? searchText[index + word.length]
          : '';

      final isWordChar = RegExp(r'\w');
      final beforeIsWord = before.isNotEmpty && isWordChar.hasMatch(before);
      final afterIsWord = after.isNotEmpty && isWordChar.hasMatch(after);

      if (beforeIsWord || afterIsWord) {
        isMatch = false;
      }
    }

    if (isMatch) {
      searchHighlights.add(
        SearchHighlight(start: index, end: index + word.length, style: style),
      );
    }

    offset = index + 1;
  }

  searchHighlightsChanged = true;
  notifyListeners();
}