textfinder.cpp Example File

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  #include <QtUiTools>
  #include <QtWidgets>
  #include "textfinder.h"

  TextFinder::TextFinder(QWidget *parent)
      : QWidget(parent)
  {
      QWidget *formWidget = loadUiFile();

      ui_findButton = findChild<QPushButton*>("findButton");
      ui_textEdit = findChild<QTextEdit*>("textEdit");
      ui_lineEdit = findChild<QLineEdit*>("lineEdit");

      QMetaObject::connectSlotsByName(this);

      loadTextFile();

      QVBoxLayout *layout = new QVBoxLayout;
      layout->addWidget(formWidget);
      setLayout(layout);

      setWindowTitle(tr("Text Finder"));
      isFirstTime = true;
  }

  QWidget* TextFinder::loadUiFile()
  {
      QUiLoader loader;

      QFile file(":/forms/textfinder.ui");
      file.open(QFile::ReadOnly);

      QWidget *formWidget = loader.load(&file, this);
      file.close();

      return formWidget;
  }

  void TextFinder::loadTextFile()
  {
      QFile inputFile(":/forms/input.txt");
      inputFile.open(QIODevice::ReadOnly);
      QTextStream in(&inputFile);
      QString line = in.readAll();
      inputFile.close();

      ui_textEdit->append(line);
      ui_textEdit->setUndoRedoEnabled(false);
      ui_textEdit->setUndoRedoEnabled(true);
  }

  void TextFinder::on_findButton_clicked()
  {
      QString searchString = ui_lineEdit->text();
      QTextDocument *document = ui_textEdit->document();

      bool found = false;

      if (isFirstTime == false)
          document->undo();

      if (searchString.isEmpty()) {
          QMessageBox::information(this, tr("Empty Search Field"),
                  "The search field is empty. Please enter a word and click Find.");
      } else {

          QTextCursor highlightCursor(document);
          QTextCursor cursor(document);

          cursor.beginEditBlock();

          QTextCharFormat plainFormat(highlightCursor.charFormat());
          QTextCharFormat colorFormat = plainFormat;
          colorFormat.setForeground(Qt::red);

          while (!highlightCursor.isNull() && !highlightCursor.atEnd()) {
              highlightCursor = document->find(searchString, highlightCursor, QTextDocument::FindWholeWords);

              if (!highlightCursor.isNull()) {
                  found = true;
                  highlightCursor.movePosition(QTextCursor::WordRight,
                                         QTextCursor::KeepAnchor);
                  highlightCursor.mergeCharFormat(colorFormat);
              }
          }

          cursor.endEditBlock();
          isFirstTime = false;

          if (found == false) {
              QMessageBox::information(this, tr("Word Not Found"),
                  "Sorry, the word cannot be found.");
          }
      }
  }