Qt 5.11 | Qt Core | MIME Type Browser Example | mainwindow.cpp Example File

Qt 5.11.3 Reference Documentation

# mainwindow.cpp Example File

mimetypes/mimetypebrowser/mainwindow.cpp

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      #include "mainwindow.h"
      #include "mimetypemodel.h"

      #include <QAction>
      #include <QApplication>
      #include <QFileDialog>
      #include <QInputDialog>
      #include <QMenu>
      #include <QMenuBar>
      #include <QMessageBox>
      #include <QPlainTextEdit>
      #include <QSplitter>
      #include <QStatusBar>
      #include <QTextEdit>
      #include <QTreeView>

      #include <QFileInfo>
      #include <QItemSelectionModel>
      #include <QMimeDatabase>
      #include <QMimeType>

      MainWindow::MainWindow(QWidget *parent)
          : QMainWindow(parent)
          , m_model(new MimetypeModel(this))
          , m_treeView(new QTreeView(this))
          , m_detailsText(new QTextEdit(this))
          , m_findIndex(0)
      {
          setWindowTitle(tr("Qt Mime Database Browser"));

          QMenu *fileMenu = menuBar()->addMenu(tr("&File"));
          QAction *detectFileAction =
              fileMenu->addAction(tr("&Detect File Type..."), this, &MainWindow::detectFile);
          detectFileAction->setShortcuts(QKeySequence::Open);

          QAction *exitAction = fileMenu->addAction(tr("E&xit"), qApp, &QApplication::closeAllWindows);
          exitAction->setShortcuts(QKeySequence::Quit);

          QMenu *findMenu = menuBar()->addMenu(tr("&Edit"));
          QAction *findAction =
              findMenu->addAction(tr("&Find..."), this, &MainWindow::find);
          findAction->setShortcuts(QKeySequence::Find);
          m_findNextAction = findMenu->addAction(tr("Find &Next"), this, &MainWindow::findNext);
          m_findNextAction->setShortcuts(QKeySequence::FindNext);
          m_findPreviousAction = findMenu->addAction(tr("Find &Previous"), this, &MainWindow::findPrevious);
          m_findPreviousAction->setShortcuts(QKeySequence::FindPrevious);

          menuBar()->addMenu(tr("&About"))->addAction(tr("&About Qt"), qApp, &QApplication::aboutQt);

          QSplitter *centralSplitter = new QSplitter(this);
          setCentralWidget(centralSplitter);
          m_treeView->setUniformRowHeights(true);
          m_treeView->setModel(m_model);

          const auto items = m_model->findItems("application/octet-stream", Qt::MatchContains | Qt::MatchFixedString | Qt::MatchRecursive);
          if (!items.isEmpty())
              m_treeView->expand(m_model->indexFromItem(items.constFirst()));

          connect(m_treeView->selectionModel(), &QItemSelectionModel::currentChanged,
                  this, &MainWindow::currentChanged);
          centralSplitter->addWidget(m_treeView);
          m_detailsText->setReadOnly(true);
          centralSplitter->addWidget(m_detailsText);

          updateFindActions();
      }

      void MainWindow::currentChanged(const QModelIndex &index)
      {
          if (index.isValid())
              m_detailsText->setText(MimetypeModel::formatMimeTypeInfo(m_model->mimeType(index)));
          else
              m_detailsText->clear();
      }

      void MainWindow::selectAndGoTo(const QModelIndex &index)
      {
          m_treeView->scrollTo(index, QAbstractItemView::PositionAtCenter);
          m_treeView->setCurrentIndex(index);
      }

      void MainWindow::detectFile()
      {
          const QString fileName = QFileDialog::getOpenFileName(this, tr("Choose File"));
          if (fileName.isEmpty())
              return;
          QMimeDatabase mimeDatabase;
          const QFileInfo fi(fileName);
          const QMimeType mimeType = mimeDatabase.mimeTypeForFile(fi);
          const QModelIndex index = mimeType.isValid()
              ? m_model->indexForMimeType(mimeType.name()) : QModelIndex();
          if (index.isValid()) {
              statusBar()->showMessage(tr("\"%1\" is of type \"%2\"").arg(fi.fileName(), mimeType.name()));
              selectAndGoTo(index);
          } else {
              QMessageBox::information(this, tr("Unknown File Type"),
                                       tr("The type of %1 could not be determined.")
                                       .arg(QDir::toNativeSeparators(fileName)));
          }
      }

      void MainWindow::updateFindActions()
      {
          const bool findNextPreviousEnabled = m_findMatches.size() > 1;
          m_findNextAction->setEnabled(findNextPreviousEnabled);
          m_findPreviousAction->setEnabled(findNextPreviousEnabled);
      }

      void MainWindow::findPrevious()
      {
          if (--m_findIndex < 0)
              m_findIndex = m_findMatches.size() - 1;
          if (m_findIndex >= 0)
              selectAndGoTo(m_findMatches.at(m_findIndex));
      }

      void MainWindow::findNext()
      {
          if (++m_findIndex >= m_findMatches.size())
              m_findIndex = 0;
          if (m_findIndex < m_findMatches.size())
              selectAndGoTo(m_findMatches.at(m_findIndex));
      }

      void MainWindow::find()
      {
          QInputDialog inputDialog(this);
          inputDialog.setWindowTitle(tr("Find"));
          inputDialog.setLabelText(tr("Text:"));
          if (inputDialog.exec() != QDialog::Accepted)
              return;
          const QString value = inputDialog.textValue().trimmed();
          if (value.isEmpty())
              return;

          m_findMatches.clear();
          m_findIndex = 0;
          foreach (const QStandardItem *item, m_model->findItems(value, Qt::MatchContains | Qt::MatchFixedString | Qt::MatchRecursive))
              m_findMatches.append(m_model->indexFromItem(item));
          statusBar()->showMessage(tr("%n mime types match \"%1\".", 0, m_findMatches.size()).arg(value));
          updateFindActions();
          if (!m_findMatches.isEmpty())
              selectAndGoTo(m_findMatches.constFirst());
      }