quartz graphics - QGraphicsTextItem mouseDoubleClickEvent -

i new guy qt. question confuses me.

code in mainwindow follows:

mainwindow::mainwindow(qwidget *parent)     : qmainwindow(parent) {     qgraphicsview *view = new qgraphicsview;     qgraphicsscene *scene =new qgraphicsscene;     graphicstextitem *item = (graphicstextitem*)scene->addtext(qstring("hello world"));     item->setpos(100,100);     scene->additem(item);     qgraphicsitem *i = scene->itemat(120,110);     view->setscene(scene);     view->show(); } 

class graphicstextitem inherits qgraphicstextitem , protected method mousepressdown reimplemented follows:

void graphicstextitem::mousedoubleclickevent(qgraphicsscenemouseevent *event) {     qdebug()<<"mousedoubleclickevent happens";     qgraphicstextitem::mousedoubleclickevent(event); } 

the application can works normally, when give graphicstextitem object double click, nothing happens mousedoubleclickevent in class graphicstextitem.

be expecting response!

i searched code , developed example, because left question here is:

#include <qgraphicstextitem>  class graphicstextitem : public qgraphicstextitem {     q_object  public:     graphicstextitem(qgraphicsitem * parent = 0);  protected:     void mousedoubleclickevent ( qgraphicsscenemouseevent * event );  }; 

implementation:

#include "graphicstextitem.h" #include <qdebug> #include <qgraphicsscenemouseevent>  graphicstextitem::graphicstextitem(qgraphicsitem * parent)     :qgraphicstextitem(parent) {     setflags(qgraphicsitem::itemismovable | qgraphicsitem::itemisselectable); }  void graphicstextitem::mousedoubleclickevent(qgraphicsscenemouseevent *event) {     if (textinteractionflags() == qt::notextinteraction)         settextinteractionflags(qt::texteditorinteraction);     qgraphicsitem::mousedoubleclickevent(event); } 

the view

#include "mainwindow.h" #include <qtgui> #include <qtcore> #include "graphicstextitem.h"  mainwindow::mainwindow(qwidget *parent) :         qmainwindow(parent) {     qgraphicsscene * scene = new qgraphicsscene();     qgraphicsview * view = new qgraphicsview();     view->setscene(scene);      graphicstextitem * text = new graphicstextitem();     text->setplaintext("hello world");     scene->additem(text);       text->setpos(100,100);     text->setflag(qgraphicsitem::itemismovable);     setcentralwidget(view); } 

in example can interact , change text qgraphicstextitem doubleclick. hope helpful.