mainwindow.cpp Example File

tools/codecs/mainwindow.cpp

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  ** This file is part of the examples of the Qt Toolkit.
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  #include <QtWidgets>

  #include "mainwindow.h"
  #include "previewform.h"

  MainWindow::MainWindow()
  {
      textEdit = new QTextEdit;
      textEdit->setLineWrapMode(QTextEdit::NoWrap);
      setCentralWidget(textEdit);

      findCodecs();

      previewForm = new PreviewForm(this);
      previewForm->setCodecList(codecs);

      createActions();
      createMenus();

      setWindowTitle(tr("Codecs"));
      resize(500, 400);
  }

  void MainWindow::open()
  {
      QString fileName = QFileDialog::getOpenFileName(this);
      if (!fileName.isEmpty()) {
          QFile file(fileName);
          if (!file.open(QFile::ReadOnly)) {
              QMessageBox::warning(this, tr("Codecs"),
                                   tr("Cannot read file %1:\n%2")
                                   .arg(fileName)
                                   .arg(file.errorString()));
              return;
          }

          QByteArray data = file.readAll();

          previewForm->setEncodedData(data);
          if (previewForm->exec())
              textEdit->setPlainText(previewForm->decodedString());
      }
  }

  void MainWindow::save()
  {
      QString fileName = QFileDialog::getSaveFileName(this);
      if (!fileName.isEmpty()) {
          QFile file(fileName);
          if (!file.open(QFile::WriteOnly | QFile::Text)) {
              QMessageBox::warning(this, tr("Codecs"),
                                   tr("Cannot write file %1:\n%2")
                                   .arg(fileName)
                                   .arg(file.errorString()));
              return;
          }

          QAction *action = qobject_cast<QAction *>(sender());
          QByteArray codecName = action->data().toByteArray();

          QTextStream out(&file);
          out.setCodec(codecName.constData());
          out << textEdit->toPlainText();
      }
  }

  void MainWindow::about()
  {
      QMessageBox::about(this, tr("About Codecs"),
              tr("The <b>Codecs</b> example demonstrates how to read and write "
                 "files using various encodings."));
  }

  void MainWindow::aboutToShowSaveAsMenu()
  {
      QString currentText = textEdit->toPlainText();

      foreach (QAction *action, saveAsActs) {
          QByteArray codecName = action->data().toByteArray();
          QTextCodec *codec = QTextCodec::codecForName(codecName);
          action->setVisible(codec && codec->canEncode(currentText));
      }
  }

  void MainWindow::findCodecs()
  {
      QMap<QString, QTextCodec *> codecMap;
      QRegExp iso8859RegExp("ISO[- ]8859-([0-9]+).*");

      foreach (int mib, QTextCodec::availableMibs()) {
          QTextCodec *codec = QTextCodec::codecForMib(mib);

          QString sortKey = codec->name().toUpper();
          int rank;

          if (sortKey.startsWith("UTF-8")) {
              rank = 1;
          } else if (sortKey.startsWith("UTF-16")) {
              rank = 2;
          } else if (iso8859RegExp.exactMatch(sortKey)) {
              if (iso8859RegExp.cap(1).size() == 1)
                  rank = 3;
              else
                  rank = 4;
          } else {
              rank = 5;
          }
          sortKey.prepend(QChar('0' + rank));

          codecMap.insert(sortKey, codec);
      }
      codecs = codecMap.values();
  }

  void MainWindow::createActions()
  {
      openAct = new QAction(tr("&Open..."), this);
      openAct->setShortcuts(QKeySequence::Open);
      connect(openAct, SIGNAL(triggered()), this, SLOT(open()));

      foreach (QTextCodec *codec, codecs) {
          QString text = tr("%1...").arg(QString(codec->name()));

          QAction *action = new QAction(text, this);
          action->setData(codec->name());
          connect(action, SIGNAL(triggered()), this, SLOT(save()));
          saveAsActs.append(action);
      }

      exitAct = new QAction(tr("E&xit"), this);
      exitAct->setShortcuts(QKeySequence::Quit);
      connect(exitAct, SIGNAL(triggered()), this, SLOT(close()));

      aboutAct = new QAction(tr("&About"), this);
      connect(aboutAct, SIGNAL(triggered()), this, SLOT(about()));

      aboutQtAct = new QAction(tr("About &Qt"), this);
      connect(aboutQtAct, SIGNAL(triggered()), qApp, SLOT(aboutQt()));
  }

  void MainWindow::createMenus()
  {
      saveAsMenu = new QMenu(tr("&Save As"), this);
      foreach (QAction *action, saveAsActs)
          saveAsMenu->addAction(action);
      connect(saveAsMenu, SIGNAL(aboutToShow()),
              this, SLOT(aboutToShowSaveAsMenu()));

      fileMenu = new QMenu(tr("&File"), this);
      fileMenu->addAction(openAct);
      fileMenu->addMenu(saveAsMenu);
      fileMenu->addSeparator();
      fileMenu->addAction(exitAct);

      helpMenu = new QMenu(tr("&Help"), this);
      helpMenu->addAction(aboutAct);
      helpMenu->addAction(aboutQtAct);

      menuBar()->addMenu(fileMenu);
      menuBar()->addSeparator();
      menuBar()->addMenu(helpMenu);
  }