mainwindow.cpp Example File
itemviews/chart/mainwindow.cpp

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 #include <QtGui>

 #include "pieview.h"
 #include "mainwindow.h"

 MainWindow::MainWindow()
 {
     QMenu *fileMenu = new QMenu(tr("&File"), this);
     QAction *openAction = fileMenu->addAction(tr("&Open..."));
     openAction->setShortcuts(QKeySequence::Open);
     QAction *saveAction = fileMenu->addAction(tr("&Save As..."));
     saveAction->setShortcuts(QKeySequence::SaveAs);
     QAction *quitAction = fileMenu->addAction(tr("E&xit"));
     quitAction->setShortcuts(QKeySequence::Quit);

     setupModel();
     setupViews();

     connect(openAction, SIGNAL(triggered()), this, SLOT(openFile()));
     connect(saveAction, SIGNAL(triggered()), this, SLOT(saveFile()));
     connect(quitAction, SIGNAL(triggered()), qApp, SLOT(quit()));

     menuBar()->addMenu(fileMenu);
     statusBar();

     openFile(":/Charts/qtdata.cht");

     setWindowTitle(tr("Chart"));
     resize(870, 550);
 }

 void MainWindow::setupModel()
 {
     model = new QStandardItemModel(8, 2, this);
     model->setHeaderData(0, Qt::Horizontal, tr("Label"));
     model->setHeaderData(1, Qt::Horizontal, tr("Quantity"));
 }

 void MainWindow::setupViews()
 {
     QSplitter *splitter = new QSplitter;
     QTableView *table = new QTableView;
     pieChart = new PieView;
     splitter->addWidget(table);
     splitter->addWidget(pieChart);
     splitter->setStretchFactor(0, 0);
     splitter->setStretchFactor(1, 1);

     table->setModel(model);
     pieChart->setModel(model);

     QItemSelectionModel *selectionModel = new QItemSelectionModel(model);
     table->setSelectionModel(selectionModel);
     pieChart->setSelectionModel(selectionModel);

     QHeaderView *headerView = table->horizontalHeader();
     headerView->setStretchLastSection(true);

     setCentralWidget(splitter);
 }

 void MainWindow::openFile(const QString &path)
 {
     QString fileName;
     if (path.isNull())
         fileName = QFileDialog::getOpenFileName(this, tr("Choose a data file"),
                                                 "", "*.cht");
     else
         fileName = path;

     if (!fileName.isEmpty()) {
         QFile file(fileName);

         if (file.open(QFile::ReadOnly | QFile::Text)) {
             QTextStream stream(&file);
             QString line;

             model->removeRows(0, model->rowCount(QModelIndex()), QModelIndex());

             int row = 0;
             do {
                 line = stream.readLine();
                 if (!line.isEmpty()) {

                     model->insertRows(row, 1, QModelIndex());

                     QStringList pieces = line.split(",", QString::SkipEmptyParts);
                     model->setData(model->index(row, 0, QModelIndex()),
                                    pieces.value(0));
                     model->setData(model->index(row, 1, QModelIndex()),
                                    pieces.value(1));
                     model->setData(model->index(row, 0, QModelIndex()),
                                    QColor(pieces.value(2)), Qt::DecorationRole);
                     row++;
                 }
             } while (!line.isEmpty());

             file.close();
             statusBar()->showMessage(tr("Loaded %1").arg(fileName), 2000);
         }
     }
 }

 void MainWindow::saveFile()
 {
     QString fileName = QFileDialog::getSaveFileName(this,
         tr("Save file as"), "", "*.cht");

     if (!fileName.isEmpty()) {
         QFile file(fileName);
         QTextStream stream(&file);

         if (file.open(QFile::WriteOnly | QFile::Text)) {
             for (int row = 0; row < model->rowCount(QModelIndex()); ++row) {

                 QStringList pieces;

                 pieces.append(model->data(model->index(row, 0, QModelIndex()),
                                           Qt::DisplayRole).toString());
                 pieces.append(model->data(model->index(row, 1, QModelIndex()),
                                           Qt::DisplayRole).toString());
                 pieces.append(model->data(model->index(row, 0, QModelIndex()),
                                           Qt::DecorationRole).toString());

                 stream << pieces.join(",") << "\n";
             }
         }

         file.close();
         statusBar()->showMessage(tr("Saved %1").arg(fileName), 2000);
     }
 }