mainwindow.cpp Example File

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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());
 }