Qt 5.9 | Qt UI Tools | Text Finder Example | textfinder.cpp Example File

Qt 5.9.2 Reference Documentation

# textfinder.cpp Example File

textfinder/textfinder.cpp

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      #include "textfinder.h"
      #include <QFile>
      #include <QLineEdit>
      #include <QMessageBox>
      #include <QPushButton>
      #include <QTextEdit>
      #include <QTextStream>
      #include <QUiLoader>
      #include <QVBoxLayout>

      static QWidget *loadUiFile(QWidget *parent)
      {
          QFile file(":/forms/textfinder.ui");
          file.open(QIODevice::ReadOnly);

          QUiLoader loader;
          return loader.load(&file, parent);
      }

      static QString loadTextFile()
      {
          QFile inputFile(":/forms/input.txt");
          inputFile.open(QIODevice::ReadOnly);
          QTextStream in(&inputFile);
          in.setCodec("UTF-8");
          return in.readAll();
      }

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

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

          QMetaObject::connectSlotsByName(this);

          ui_textEdit->setText(loadTextFile());

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

          setWindowTitle(tr("Text Finder"));
      }

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

          bool found = false;

          // undo previous change (if any)
          document->undo();

          if (searchString.isEmpty()) {
              QMessageBox::information(this, tr("Empty Search Field"),
                                       tr("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();

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