原工程：tools/undoframework.pro

//==========================mainwindow.h

//add the slot into mainwindow.h

private slots:

//Jingz添加 void hideItem(); //     void deleteItem();

//add the action into mainwindow.h

private:

    void createActions();     void createMenus();     void createUndoView(); //Jingz添加 QAction *hideAction; //

//==========================mainwindow.cpp

//! [2] initialize the action

void MainWindow::createActions() {     deleteAction = new QAction(tr("&Delete Item"), this);     deleteAction->setShortcut(tr("Del"));     connect(deleteAction, SIGNAL(triggered()), this, SLOT(deleteItem())); //! [2] //! [3] -------------------------------------------------------------------------- Jingz  hideAction = new QAction(tr("&Hide Item"),this); hideAction->setShortcut(tr("Ctrl+H")); connect(hideAction,SIGNAL(triggered()),this,SLOT(hideItem())); //! [3] //! [4]

.............

undoAction = undoStack->createUndoAction(this, tr("&Undo"));

    undoAction->setShortcuts(QKeySequence::Undo);     redoAction = undoStack->createRedoAction(this, tr("&Redo"));     redoAction->setShortcuts(QKeySequence::Redo); ...............

void MainWindow::createMenus()

{ //! [6]     fileMenu = menuBar()->addMenu(tr("&File"));     fileMenu->addAction(exitAction); //! [7]     editMenu = menuBar()->addMenu(tr("&Edit"));     editMenu->addAction(undoAction);     editMenu->addAction(redoAction);     editMenu->addSeparator();     editMenu->addAction(deleteAction); editMenu->addAction(hideAction);//---------------------------------Jingz add the action into menu

..............................

//! [16] ================Jingz realize hidItem 

void MainWindow::hideItem() { if (diagramScene->selectedItems().isEmpty()) return; QUndoCommand *hideCommand = new HideCommand(diagramScene); 

//operation  to change the item status and keep previous diagramScene in the undoStack 

undoStack->push(hideCommand);//把压制的代码解决就行啦。 } //! [16]

//! [3]   ================================================commands.h    Jingz

class HideCommand : public QUndoCommand { public: HideCommand(QGraphicsScene *graphicsScene, QUndoCommand *parent = 0); ~HideCommand(); void undo(); void redo(); private: DiagramItem *myDiagramItem; QGraphicsScene *myGraphicsScene; //QList <int> hideGraphics; //int undoIndex; }; //! [3]

//! [10]=================================================commands.cpp Jingz

HideCommand::HideCommand(QGraphicsScene *scene,QUndoCommand *parent) : QUndoCommand(parent) { myGraphicsScene = scene; QList<QGraphicsItem *> list = myGraphicsScene->selectedItems(); myGraphicsScene->selectedItems().first()->setVisible(false); list.first()->setSelected(false); myDiagramItem = static_cast<DiagramItem *>(list.first()); //QList<QGraphicsItem *> list = myGraphicsScene->selectedItems(); //list.first()->setSelected(false); //myDiagramItem = static_cast<DiagramItem *>(list.first()); //setText(QObject::tr("Delete %1") // .arg(createCommandString(myDiagramItem, myDiagramItem->pos()))); //if (hideGraphics.count()>undoIndex)//当出现undo后做新修改，覆盖后面的redo记录 //{ // hideGraphics.pop_back(); //} //for (int i = 0;i < myGraphicsScene->items().count();i++ ) //{ // myDiagramItem = static_cast<DiagramItem *>(myGraphicsScene->items().value(i)); // if (!myGraphicsScene->items().value(i)->isVisible()) // { // myGraphicsScene->items().value(i)->show(); // setText(QObject::tr("Show %1").arg(createCommandString(myDiagramItem, myDiagramItem->pos()))); // } // //} // QList<QGraphicsItem *> list = myGraphicsScene->selectedItems(); /*for (int i = 0;i < myGraphicsScene->selectedItems().count();i++) { myGraphicsScene->selectedItems().value(i)->hide(); myDiagramItem = static_cast<DiagramItem *>(myGraphicsScene->selectedItems().value(i)); myGraphicsScene->selectedItems().value(i)->setSelected(false); hideGraphics.append(i); undoIndex = hideGraphics.count(); setText(QObject::tr("Hide %1").arg(createCommandString(myDiagramItem, myDiagramItem->pos()))); }*/ // myGraphicsScene->update(); //myGraphicsScene->selectedItems().first()->setSelected(false); setText(QObject::tr("Hide %1").arg(createCommandString(myDiagramItem, myDiagramItem->pos()))); } //! [10] HideCommand::~HideCommand() { /*if (!myDiagramItem->scene()) delete myDiagramItem;*/ } //! [11] void HideCommand::undo() { /*int i = hideGraphics.at(--undoIndex);*///撤销本次操作 //if (myGraphicsScene->items().at(i)->isVisible()) //{ // myGraphicsScene->items().at(i)->hide(); //} //else //{ // myGraphicsScene->items().at(i)->show(); //}// //i = hideGraphics.at(--undoIndex);//恢复现场 //if (myGraphicsScene->items().at(i)->isVisible()) //{ // myGraphicsScene->items().at(i)->hide(); //} //else //{ // myGraphicsScene->items().at(i)->show(); //} // myGraphicsScene->items().at(i)->setVisible(false); myDiagramItem->setVisible(true); myGraphicsScene->update(); } //! [11] //! [12] void HideCommand::redo() { /*int i = hideGraphics.at(++undoIndex);*/ /*if (myGraphicsScene->items().at(i)->isVisible()) { myGraphicsScene->items().at(i)->hide(); } else { myGraphicsScene->items().at(i)->show(); } i = hideGraphics.at(++undoIndex); if (myGraphicsScene->items().at(i)->isVisible()) { myGraphicsScene->items().at(i)->hide(); } else { myGraphicsScene->items().at(i)->show(); }*/ /*myGraphicsScene->items().at(i)->setVisible(true);*/ myDiagramItem->setVisible(false); myGraphicsScene->update(); } //! [12] QString createCommandString(DiagramItem *item, const QPointF &pos) {     return QObject::tr("%1 at (%2, %3)")         .arg(item->diagramType() == DiagramItem::Box ? "Box" : "Triangle")         .arg(pos.x()).arg(pos.y()); }