qt - open a QGraphicScene child widget in the mainwindow -

i'm trying create qgraphicscene (with appropriate view) in mainwindow. scene defined in seperate class (a child widget mainwindow).

the open action works , can open every picture, open in new window , not within in mainwindow.

when create label (or so) in child widget, displayed correctly within mainwindow. problem seems qgraphicscene or qgraphicview.

mainwindow:

mainwindow::mainwindow() {     qwidget *widget = new qwidget;     setcentralwidget(widget);      picturearea = new picturearea(this);      qhboxlayout *hlayout = new qhboxlayout(this);       hlayout->addwidget(picturearea,1);         widget->setlayout(hlayout);       createactions();                               createmenus();                      this->setminimumsize(800,600);     this->resize(800,600);   }  ...  void mainwindow::open() {     qstring filename = qfiledialog::getopenfilename(this, tr("open image"),       qdir::currentpath(), tr("image files (*.png *.jpg)"));      if (!filename.isempty())     {         qimage image(filename);         if (image.isnull())         {             qmessagebox::information(this, tr("image viewer"),              tr("cannot load %1.").arg(filename));             return;         }         //transfer child widget, guess no mistakes far         picturearea->setpicture(image);            }   } 

picturearea:

picturearea::picturearea(qwidget *parent) : qwidget(parent) {    }  void picturearea::setpicture(qimage image) {        qgraphicsscene* scene = new qgraphicsscene();     qgraphicsview* view = new qgraphicsview(scene);      qgraphicspixmapitem* item =                  new qgraphicspixmapitem(qpixmap::fromimage(image));     scene->additem(item);      view->show(); } 

how can create scene within mainwindow , not in separate window? i'm using qt 4.7.4, windows7 64bit.

you creating new qgraphicsscene , qgraphicsview every time set picture. , not putting view inside layout or setting parent it, it's opening in new window when call view->show().

you should create qgraphicsview , qgraphicsscene inside constructor.

//picturearea.h ... public:     qgraphicsview *view;     qgraphicsscene *scene;         ... 

 

//pircurearea.cpp picturearea::picturearea(qwidget *parent) : qwidget(parent) {     this->setlayout(new qvboxlayout);     view = new qgraphicsview(this);     this->layout()->addwidget(view);     scene = new qgraphicsscene;     view->setscene(scene); }  void picturearea::setpicture(qimage image) {     scene->clear();     scene->addpixmap(qpixmap::fromimage(image)); }