Qt 5.11 | Qt Widgets | Undo Framework | mainwindow.cpp Example File

Qt 5.11.3 Reference Documentation

# mainwindow.cpp Example File

tools/undo/mainwindow.cpp

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      #include <QUndoGroup>
      #include <QUndoStack>
      #include <QFileDialog>
      #include <QMessageBox>
      #include <QRandomGenerator>
      #include <QTextStream>
      #include <QToolButton>
      #include "document.h"
      #include "mainwindow.h"
      #include "commands.h"

      MainWindow::MainWindow(QWidget *parent)
          : QMainWindow(parent)
      {
          setupUi(this);

          QWidget *w = documentTabs->widget(0);
          documentTabs->removeTab(0);
          delete w;

          connect(actionOpen, SIGNAL(triggered()), this, SLOT(openDocument()));
          connect(actionClose, SIGNAL(triggered()), this, SLOT(closeDocument()));
          connect(actionNew, SIGNAL(triggered()), this, SLOT(newDocument()));
          connect(actionSave, SIGNAL(triggered()), this, SLOT(saveDocument()));
          connect(actionExit, SIGNAL(triggered()), this, SLOT(close()));
          connect(actionRed, SIGNAL(triggered()), this, SLOT(setShapeColor()));
          connect(actionGreen, SIGNAL(triggered()), this, SLOT(setShapeColor()));
          connect(actionBlue, SIGNAL(triggered()), this, SLOT(setShapeColor()));
          connect(actionAddCircle, SIGNAL(triggered()), this, SLOT(addShape()));
          connect(actionAddRectangle, SIGNAL(triggered()), this, SLOT(addShape()));
          connect(actionAddTriangle, SIGNAL(triggered()), this, SLOT(addShape()));
          connect(actionRemoveShape, SIGNAL(triggered()), this, SLOT(removeShape()));
          connect(actionAddRobot, SIGNAL(triggered()), this, SLOT(addRobot()));
          connect(actionAddSnowman, SIGNAL(triggered()), this, SLOT(addSnowman()));
          connect(actionAbout, SIGNAL(triggered()), this, SLOT(about()));
          connect(actionAboutQt, SIGNAL(triggered()), this, SLOT(aboutQt()));

          connect(undoLimit, SIGNAL(valueChanged(int)), this, SLOT(updateActions()));
          connect(documentTabs, SIGNAL(currentChanged(int)), this, SLOT(updateActions()));

          actionOpen->setShortcut(QString("Ctrl+O"));
          actionClose->setShortcut(QString("Ctrl+W"));
          actionNew->setShortcut(QString("Ctrl+N"));
          actionSave->setShortcut(QString("Ctrl+S"));
          actionExit->setShortcut(QString("Ctrl+Q"));
          actionRemoveShape->setShortcut(QString("Del"));
          actionRed->setShortcut(QString("Alt+R"));
          actionGreen->setShortcut(QString("Alt+G"));
          actionBlue->setShortcut(QString("Alt+B"));
          actionAddCircle->setShortcut(QString("Alt+C"));
          actionAddRectangle->setShortcut(QString("Alt+L"));
          actionAddTriangle->setShortcut(QString("Alt+T"));

          m_undoGroup = new QUndoGroup(this);
          undoView->setGroup(m_undoGroup);
          undoView->setCleanIcon(QIcon(":/icons/ok.png"));

          QAction *undoAction = m_undoGroup->createUndoAction(this);
          QAction *redoAction = m_undoGroup->createRedoAction(this);
          undoAction->setIcon(QIcon(":/icons/undo.png"));
          redoAction->setIcon(QIcon(":/icons/redo.png"));
          menuShape->insertAction(menuShape->actions().at(0), undoAction);
          menuShape->insertAction(undoAction, redoAction);

          toolBar->addAction(undoAction);
          toolBar->addAction(redoAction);

          newDocument();
          updateActions();
      };

      void MainWindow::updateActions()
      {
          Document *doc = currentDocument();
          m_undoGroup->setActiveStack(doc == 0 ? 0 : doc->undoStack());
          QString shapeName = doc == 0 ? QString() : doc->currentShapeName();

          actionAddRobot->setEnabled(doc != 0);
          actionAddSnowman->setEnabled(doc != 0);
          actionAddCircle->setEnabled(doc != 0);
          actionAddRectangle->setEnabled(doc != 0);
          actionAddTriangle->setEnabled(doc != 0);
          actionClose->setEnabled(doc != 0);
          actionSave->setEnabled(doc != 0 && !doc->undoStack()->isClean());
          undoLimit->setEnabled(doc != 0 && doc->undoStack()->count() == 0);

          if (shapeName.isEmpty()) {
              actionRed->setEnabled(false);
              actionGreen->setEnabled(false);
              actionBlue->setEnabled(false);
              actionRemoveShape->setEnabled(false);
          } else {
              Shape shape = doc->shape(shapeName);
              actionRed->setEnabled(shape.color() != Qt::red);
              actionGreen->setEnabled(shape.color() != Qt::green);
              actionBlue->setEnabled(shape.color() != Qt::blue);
              actionRemoveShape->setEnabled(true);
          }

          if (doc != 0) {
              int index = documentTabs->indexOf(doc);
              Q_ASSERT(index != -1);
              static const QIcon unsavedIcon(":/icons/filesave.png");
              documentTabs->setTabIcon(index, doc->undoStack()->isClean() ? QIcon() : unsavedIcon);

              if (doc->undoStack()->count() == 0)
                  doc->undoStack()->setUndoLimit(undoLimit->value());
          }
      }

      void MainWindow::openDocument()
      {
          QString fileName = QFileDialog::getOpenFileName(this);
          if (fileName.isEmpty())
              return;

          QFile file(fileName);
          if (!file.open(QIODevice::ReadOnly)) {
              QMessageBox::warning(this,
                                  tr("File error"),
                                  tr("Failed to open\n%1").arg(fileName));
              return;
          }
          QTextStream stream(&file);

          Document *doc = new Document();
          if (!doc->load(stream)) {
              QMessageBox::warning(this,
                                  tr("Parse error"),
                                  tr("Failed to parse\n%1").arg(fileName));
              delete doc;
              return;
          }

          doc->setFileName(fileName);
          addDocument(doc);
      }

      QString MainWindow::fixedWindowTitle(const Document *doc) const
      {
          QString title = doc->fileName();

          if (title.isEmpty())
              title = tr("Unnamed");
          else
              title = QFileInfo(title).fileName();

          QString result;

          for (int i = 0; ; ++i) {
              result = title;
              if (i > 0)
                  result += QString::number(i);

              bool unique = true;
              for (int j = 0; j < documentTabs->count(); ++j) {
                  const QWidget *widget = documentTabs->widget(j);
                  if (widget == doc)
                      continue;
                  if (result == documentTabs->tabText(j)) {
                      unique = false;
                      break;
                  }
              }

              if (unique)
                  break;
          }

          return result;
      }

      void MainWindow::addDocument(Document *doc)
      {
          if (documentTabs->indexOf(doc) != -1)
              return;
          m_undoGroup->addStack(doc->undoStack());
          documentTabs->addTab(doc, fixedWindowTitle(doc));
          connect(doc, SIGNAL(currentShapeChanged(QString)), this, SLOT(updateActions()));
          connect(doc->undoStack(), SIGNAL(indexChanged(int)), this, SLOT(updateActions()));
          connect(doc->undoStack(), SIGNAL(cleanChanged(bool)), this, SLOT(updateActions()));

          setCurrentDocument(doc);
      }

      void MainWindow::setCurrentDocument(Document *doc)
      {
          documentTabs->setCurrentWidget(doc);
      }

      Document *MainWindow::currentDocument() const
      {
          return qobject_cast<Document*>(documentTabs->currentWidget());
      }

      void MainWindow::removeDocument(Document *doc)
      {
          int index = documentTabs->indexOf(doc);
          if (index == -1)
              return;

          documentTabs->removeTab(index);
          m_undoGroup->removeStack(doc->undoStack());
          disconnect(doc, SIGNAL(currentShapeChanged(QString)), this, SLOT(updateActions()));
          disconnect(doc->undoStack(), SIGNAL(indexChanged(int)), this, SLOT(updateActions()));
          disconnect(doc->undoStack(), SIGNAL(cleanChanged(bool)), this, SLOT(updateActions()));

          if (documentTabs->count() == 0) {
              newDocument();
              updateActions();
          }
      }

      void MainWindow::saveDocument()
      {
          Document *doc = currentDocument();
          if (doc == 0)
              return;

          for (;;) {
              QString fileName = doc->fileName();

              if (fileName.isEmpty())
                  fileName = QFileDialog::getSaveFileName(this);
              if (fileName.isEmpty())
                  break;

              QFile file(fileName);
              if (!file.open(QIODevice::WriteOnly)) {
                  QMessageBox::warning(this,
                                      tr("File error"),
                                      tr("Failed to open\n%1").arg(fileName));
                  doc->setFileName(QString());
              } else {
                  QTextStream stream(&file);
                  doc->save(stream);
                  doc->setFileName(fileName);

                  int index = documentTabs->indexOf(doc);
                  Q_ASSERT(index != -1);
                  documentTabs->setTabText(index, fixedWindowTitle(doc));

                  break;
              }
          }
      }

      void MainWindow::closeDocument()
      {
          Document *doc = currentDocument();
          if (doc == 0)
              return;

          if (!doc->undoStack()->isClean()) {
              int button
                  = QMessageBox::warning(this,
                                  tr("Unsaved changes"),
                                  tr("Would you like to save this document?"),
                                  QMessageBox::Yes, QMessageBox::No);
              if (button == QMessageBox::Yes)
                  saveDocument();
          }

          removeDocument(doc);
          delete doc;
      }

      void MainWindow::newDocument()
      {
          addDocument(new Document());
      }

      static QColor randomColor()
      {
          int r = QRandomGenerator::global()->bounded(3);
          switch (r) {
              case 0:
                  return Qt::red;
              case 1:
                  return Qt::green;
              default:
                  break;
          }
          return Qt::blue;
      }

      static QRect randomRect(const QSize &s)
      {
          QSize min = Shape::minSize;

          int left = (int) ((0.0 + s.width() - min.width())*(QRandomGenerator::global()->bounded(1.0)));
          int top = (int) ((0.0 + s.height() - min.height())*(QRandomGenerator::global()->bounded(1.0)));
          int width = (int) ((0.0 + s.width() - left - min.width())*(QRandomGenerator::global()->bounded(1.0))) + min.width();
          int height = (int) ((0.0 + s.height() - top - min.height())*(QRandomGenerator::global()->bounded(1.0))) + min.height();

          return QRect(left, top, width, height);
      }

      void MainWindow::addShape()
      {
          Document *doc = currentDocument();
          if (doc == 0)
              return;

          Shape::Type type;

          if (sender() == actionAddCircle)
              type = Shape::Circle;
          else if (sender() == actionAddRectangle)
              type = Shape::Rectangle;
          else if (sender() == actionAddTriangle)
              type = Shape::Triangle;
          else return;

          Shape newShape(type, randomColor(), randomRect(doc->size()));
          doc->undoStack()->push(new AddShapeCommand(doc, newShape));
      }

      void MainWindow::removeShape()
      {
          Document *doc = currentDocument();
          if (doc == 0)
              return;

          QString shapeName = doc->currentShapeName();
          if (shapeName.isEmpty())
              return;

          doc->undoStack()->push(new RemoveShapeCommand(doc, shapeName));
      }

      void MainWindow::setShapeColor()
      {
          Document *doc = currentDocument();
          if (doc == 0)
              return;

          QString shapeName = doc->currentShapeName();
          if (shapeName.isEmpty())
              return;

          QColor color;

          if (sender() == actionRed)
              color = Qt::red;
          else if (sender() == actionGreen)
              color = Qt::green;
          else if (sender() == actionBlue)
              color = Qt::blue;
          else
              return;

          if (color == doc->shape(shapeName).color())
              return;

          doc->undoStack()->push(new SetShapeColorCommand(doc, shapeName, color));
      }

      void MainWindow::addSnowman()
      {
          Document *doc = currentDocument();
          if (doc == 0)
              return;

          // Create a macro command using beginMacro() and endMacro()

          doc->undoStack()->beginMacro(tr("Add snowman"));
          doc->undoStack()->push(new AddShapeCommand(doc,
                                  Shape(Shape::Circle, Qt::blue, QRect(51, 30, 97, 95))));
          doc->undoStack()->push(new AddShapeCommand(doc,
                                  Shape(Shape::Circle, Qt::blue, QRect(27, 123, 150, 133))));
          doc->undoStack()->push(new AddShapeCommand(doc,
                                  Shape(Shape::Circle, Qt::blue, QRect(11, 253, 188, 146))));
          doc->undoStack()->endMacro();
      }

      void MainWindow::addRobot()
      {
          Document *doc = currentDocument();
          if (doc == 0)
              return;

          // Compose a macro command by explicitly adding children to a parent command

          QUndoCommand *parent = new QUndoCommand(tr("Add robot"));

          new AddShapeCommand(doc, Shape(Shape::Rectangle, Qt::green, QRect(115, 15, 81, 70)), parent);
          new AddShapeCommand(doc, Shape(Shape::Rectangle, Qt::green, QRect(82, 89, 148, 188)), parent);
          new AddShapeCommand(doc, Shape(Shape::Rectangle, Qt::green, QRect(76, 280, 80, 165)), parent);
          new AddShapeCommand(doc, Shape(Shape::Rectangle, Qt::green, QRect(163, 280, 80, 164)), parent);
          new AddShapeCommand(doc, Shape(Shape::Circle, Qt::blue, QRect(116, 25, 80, 50)), parent);
          new AddShapeCommand(doc, Shape(Shape::Rectangle, Qt::green, QRect(232, 92, 80, 127)), parent);
          new AddShapeCommand(doc, Shape(Shape::Rectangle, Qt::green, QRect(2, 92, 80, 125)), parent);

          doc->undoStack()->push(parent);
      }

      void MainWindow::about()
      {
          QMessageBox::about(this, tr("About Undo"), tr("The Undo demonstration shows how to use the Qt Undo framework."));
      }

      void MainWindow::aboutQt()
      {
          QMessageBox::aboutQt(this, tr("About Qt"));
      }