languagechooser.cpp Example File

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  #include <QtWidgets>

  #include "languagechooser.h"
  #include "mainwindow.h"

  #ifdef Q_DEAD_CODE_FROM_QT4_MAC
  extern void qt_mac_set_menubar_merge(bool merge);

  #endif

  LanguageChooser::LanguageChooser(const QString& defaultLang, QWidget *parent)
      : QDialog(parent, Qt::WindowStaysOnTopHint)
  {
      groupBox = new QGroupBox("Languages");

      QGridLayout *groupBoxLayout = new QGridLayout;

      QStringList qmFiles = findQmFiles();
      for (int i = 0; i < qmFiles.size(); ++i) {
          QCheckBox *checkBox = new QCheckBox(languageName(qmFiles[i]));
          qmFileForCheckBoxMap.insert(checkBox, qmFiles[i]);
          connect(checkBox, SIGNAL(toggled(bool)), this, SLOT(checkBoxToggled()));
          if (languageMatch(defaultLang, qmFiles[i]))
                  checkBox->setCheckState(Qt::Checked);
          groupBoxLayout->addWidget(checkBox, i / 2, i % 2);
      }
      groupBox->setLayout(groupBoxLayout);

      buttonBox = new QDialogButtonBox;

      showAllButton = buttonBox->addButton("Show All",
                                           QDialogButtonBox::ActionRole);
      hideAllButton = buttonBox->addButton("Hide All",
                                           QDialogButtonBox::ActionRole);

      connect(showAllButton, SIGNAL(clicked()), this, SLOT(showAll()));
      connect(hideAllButton, SIGNAL(clicked()), this, SLOT(hideAll()));

      QVBoxLayout *mainLayout = new QVBoxLayout;
      mainLayout->addWidget(groupBox);
      mainLayout->addWidget(buttonBox);
      setLayout(mainLayout);

  #ifdef Q_DEAD_CODE_FROM_QT4_MAC
      qt_mac_set_menubar_merge(false);
  #endif

      setWindowTitle("I18N");
  }

  bool LanguageChooser::languageMatch(const QString& lang, const QString& qmFile)
  {
      //qmFile: i18n_xx.qm
      const QString prefix = "i18n_";
      const int langTokenLength = 2; /*FIXME: is checking two chars enough?*/
      return qmFile.midRef(qmFile.indexOf(prefix) + prefix.length(), langTokenLength) == lang.leftRef(langTokenLength);
  }

  bool LanguageChooser::eventFilter(QObject *object, QEvent *event)
  {
      if (event->type() == QEvent::Close) {
          MainWindow *window = qobject_cast<MainWindow *>(object);
          if (window) {
              QCheckBox *checkBox = mainWindowForCheckBoxMap.key(window);
              if (checkBox)
                  checkBox->setChecked(false);
          }
      }
      return QWidget::eventFilter(object, event);
  }

  void LanguageChooser::closeEvent(QCloseEvent * /* event */)
  {
      qApp->quit();
  }

  void LanguageChooser::checkBoxToggled()
  {
      QCheckBox *checkBox = qobject_cast<QCheckBox *>(sender());
      MainWindow *window = mainWindowForCheckBoxMap[checkBox];
      if (!window) {
          QTranslator translator;
          translator.load(qmFileForCheckBoxMap[checkBox]);
          qApp->installTranslator(&translator);

          window = new MainWindow;
          window->setPalette(colorForLanguage(checkBox->text()));

          window->installEventFilter(this);
          mainWindowForCheckBoxMap.insert(checkBox, window);
      }
      window->setVisible(checkBox->isChecked());
  }

  void LanguageChooser::showAll()
  {
      foreach (QCheckBox *checkBox, qmFileForCheckBoxMap.keys())
          checkBox->setChecked(true);
  }

  void LanguageChooser::hideAll()
  {
      foreach (QCheckBox *checkBox, qmFileForCheckBoxMap.keys())
          checkBox->setChecked(false);
  }

  QStringList LanguageChooser::findQmFiles()
  {
      QDir dir(":/translations");
      QStringList fileNames = dir.entryList(QStringList("*.qm"), QDir::Files,
                                            QDir::Name);
      QMutableStringListIterator i(fileNames);
      while (i.hasNext()) {
          i.next();
          i.setValue(dir.filePath(i.value()));
      }
      return fileNames;
  }

  QString LanguageChooser::languageName(const QString &qmFile)
  {
      QTranslator translator;
      translator.load(qmFile);

      return translator.translate("MainWindow", "English");
  }

  QColor LanguageChooser::colorForLanguage(const QString &language)
  {
      uint hashValue = qHash(language);
      int red = 156 + (hashValue & 0x3F);
      int green = 156 + ((hashValue >> 6) & 0x3F);
      int blue = 156 + ((hashValue >> 12) & 0x3F);
      return QColor(red, green, blue);
  }