How to make MDI editor with QGraphicsView support

[Kuzemko]

Hello All!
I am a notice in Qt-programming.
I need MDI editor with support QGraphicsScene and QGraphicsView. I see example in Qt docs, and make some change to it.
But I have a wrong result.
In constructor I add text "Hello" to the scene, but I not see it on the screen.
I think that I write wrong constructor

SymbolEditor::SymbolEditor(QWidget *parent)
: QGraphicsView(parent)
{
QGraphicsScene symbolEditorScene;
symbolEditorScene.addText("Hello");
QGraphicsView symbolEditorView(&symbolEditorScene);
symbolEditorView.setRenderHint(QPainter::Antialias ing);
symbolEditorView.setCacheMode(QGraphicsView::Cache Background);
//symbolEditorView.show();
symbolAction = new QAction(this);
symbolAction->setCheckable(true);
connect(symbolAction, SIGNAL(triggered()), this, SLOT(show()));
connect(symbolAction,SIGNAL(triggered()), this,SLOT(setFocus()));

isUntitled = true;
modified=false;
selected=false;
fileSymbolFilters = tr("Файлы символов УГО (*.ksef)\n"
"Все файлы (*)");
connect(this, SIGNAL(contentsChanged()),this, SLOT(documentWasModified()));

symbolEditorView.setWindowIcon(QPixmap(":/images/document.png"));
symbolEditorView.setAttribute(Qt::WA_DeleteOnClose );
}

And when I close active window it closed but I can see it in windows list in menu.
Please help me.

[aamer4yu]

As i can see u have inherited symbolEditor from QGraphicsView. So this represents a view class.

U need to set the scene for this view from outside the class..
such as view->setScene(scene);

can u give the class declaration of symboEditor?? will help to know ur design..

[fullmetalcoder]

SymbolEditor::SymbolEditor(QWidget *parent)
    : QGraphicsView(parent)
{
    QGraphicsScene symbolEditorScene;
    symbolEditorScene.addText("Hello");
    QGraphicsView symbolEditorView(&symbolEditorScene);
    symbolEditorView.setRenderHint(QPainter::Antialiasing);
    symbolEditorView.setCacheMode(QGraphicsView::CacheBackground);
    //symbolEditorView.show();
    symbolAction = new QAction(this);
    symbolAction->setCheckable(true);
    connect(symbolAction, SIGNAL(triggered()), this, SLOT(show()));
    connect(symbolAction,SIGNAL(triggered()), this,SLOT(setFocus()));
 
    isUntitled = true;
    modified=false;
    selected=false;
    fileSymbolFilters = tr("Файлы символов УГО (*.ksef)\n"
                     "Все файлы (*)");
    connect(this, SIGNAL(contentsChanged()),this, SLOT(documentWasModified()));
 
    symbolEditorView.setWindowIcon(QPixmap(":/images/document.png"));
    symbolEditorView.setAttribute(Qt::WA_DeleteOnClose);
}

SymbolEditor::SymbolEditor(QWidget *parent)
    : QGraphicsView(parent)
{
    QGraphicsScene symbolEditorScene;
    symbolEditorScene.addText("Hello");
    QGraphicsView symbolEditorView(&symbolEditorScene);
    symbolEditorView.setRenderHint(QPainter::Antialiasing);
    symbolEditorView.setCacheMode(QGraphicsView::CacheBackground);
    //symbolEditorView.show();
    symbolAction = new QAction(this);
    symbolAction->setCheckable(true);
    connect(symbolAction, SIGNAL(triggered()), this, SLOT(show()));
    connect(symbolAction,SIGNAL(triggered()), this,SLOT(setFocus()));

    isUntitled = true;
    modified=false;
    selected=false;
    fileSymbolFilters = tr("Файлы символов УГО (*.ksef)\n"
                     "Все файлы (*)");
    connect(this, SIGNAL(contentsChanged()),this, SLOT(documentWasModified()));

    symbolEditorView.setWindowIcon(QPixmap(":/images/document.png"));
    symbolEditorView.setAttribute(Qt::WA_DeleteOnClose);
}

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There's something wrong in your code : your SymbolEditor class inherits from QGraphicsView but creates another QGraphicsView inside its constructor... Moreover the internaly created QGraphicsView has no chance to be seen because :

• it is allocated on heap (i.e. it's not a pointer...) and will be destroyed just at the end of the constructor...
• the QWidget::show() method is not called

here is what I suggest :

SymbolEditor::SymbolEditor(QWidget *parent)
    : QGraphicsView(parent)
{
 QGraphicsScene *symbolEditorScene = new QGraphicsScene;
 symbolEditorScene->addText("Hello");
 
 setScene(symbolEditorScene);
 setRenderHint(QPainter::Antialiasing);
 setCacheMode(QGraphicsView::CacheBackground);
 
 symbolAction = new QAction(this);
 symbolAction->setCheckable(true);
 connect(symbolAction, SIGNAL(triggered()), this, SLOT(show()));
 connect(symbolAction,SIGNAL(triggered()), this,SLOT(setFocus()));
 
 isUntitled = true;
 modified=false;
 selected=false;
 fileSymbolFilters = tr("Файлы символов УГО (*.ksef)\n"
 "Все файлы (*)");
 connect(this, SIGNAL(contentsChanged()),this, SLOT(documentWasModified()));
 
 setWindowIcon(QPixmap(":/images/document.png"));
 setAttribute(Qt::WA_DeleteOnClose);
 
 show();
}

SymbolEditor::SymbolEditor(QWidget *parent)
    : QGraphicsView(parent)
{
 QGraphicsScene *symbolEditorScene = new QGraphicsScene;
 symbolEditorScene->addText("Hello");
 
 setScene(symbolEditorScene);
 setRenderHint(QPainter::Antialiasing);
 setCacheMode(QGraphicsView::CacheBackground);
 
 symbolAction = new QAction(this);
 symbolAction->setCheckable(true);
 connect(symbolAction, SIGNAL(triggered()), this, SLOT(show()));
 connect(symbolAction,SIGNAL(triggered()), this,SLOT(setFocus()));
  
 isUntitled = true;
 modified=false;
 selected=false;
 fileSymbolFilters = tr("Файлы символов УГО (*.ksef)\n"
 "Все файлы (*)");
 connect(this, SIGNAL(contentsChanged()),this, SLOT(documentWasModified()));
  
 setWindowIcon(QPixmap(":/images/document.png"));
 setAttribute(Qt::WA_DeleteOnClose);
 
 show();
}

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Hope this helps.

[Kuzemko]

Thanks, It work!

[Kuzemko]

I need realize in the program, that 1 pixel on the screen corresponded 0.001mm on a paper. Help me as it to realize.