Qt 5.11 | Qt Widgets | Chart Example | mainwindow.cpp Example File

Qt 5.11.3 Reference Documentation

# mainwindow.cpp Example File

itemviews/chart/mainwindow.cpp

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      #include <QtWidgets>

      #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, &QAction::triggered, this, &MainWindow::openFile);
          connect(saveAction, &QAction::triggered, this, &MainWindow::saveFile);
          connect(quitAction, &QAction::triggered, qApp, &QCoreApplication::quit);

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

          loadFile(":/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 fileName =
              QFileDialog::getOpenFileName(this, tr("Choose a data file"), "", "*.cht");
          if (!fileName.isEmpty())
              loadFile(fileName);
      }

      void MainWindow::loadFile(const QString &fileName)
      {
          QFile file(fileName);
          if (!file.open(QFile::ReadOnly | QFile::Text))
              return;

          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())
              return;

          QFile file(fileName);
          if (!file.open(QFile::WriteOnly | QFile::Text))
              return;

          QTextStream stream(&file);
          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);
      }