mainwindow.cpp Example File

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  #include <QUndoGroup>
  #include <QUndoStack>
  #include <QFileDialog>
  #include <QMessageBox>
  #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 = (int) (3.0*(rand()/(RAND_MAX + 1.0)));
      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())*(rand()/(RAND_MAX + 1.0)));
      int top = (int) ((0.0 + s.height() - min.height())*(rand()/(RAND_MAX + 1.0)));
      int width = (int) ((0.0 + s.width() - left - min.width())*(rand()/(RAND_MAX + 1.0))) + min.width();
      int height = (int) ((0.0 + s.height() - top - min.height())*(rand()/(RAND_MAX + 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"));
  }