can not paint picture in a widget which inside a qsrcollarea

[hashb]

Hi All,

I want to paint pic to a widget which inside a qscroll area,
but it seems no pic paint out

here is my code :

class Widget2 : public QWidget{
    public:
        Widget2(QWidget *parent)    {  }
    protected:
        void paintEvent(QPaintEvent*) 
        {
            QPainter realPainter(this);
            realPainter.drawPixmap(0,0,QPixmap("./01.png"));
        }
    };
 
 
 
    class Widget : public QScrollArea{
    public:
       Widget(QWidget *parent=0)
        {
            w_ = new QWidget(this);
            w_->resize(3000,3000);
           setWidget(w_);
        }
    protected:
        void paintEvent(QPaintEvent*)
        {
            QPainter realPainter(w_);
            realPainter.drawPixmap(0,0,QPixmap("./01.png"));
        }
    private:
        QWidget *w_;
    };
 
int main(int argc ,char *argv[])
{
    QApplication app(argc,argv);
    Widget w;
    w.show(); //the picture not paint out!!!
    ////////////////////////////
    //the code blow works ,I was wondering why?:confused:
    //Widget2 w;
    //w.show(); //the picture not paint out!!!
    /////////////////////////
 
    app.exec();
 
 
}

class Widget2 : public QWidget{
    public:
        Widget2(QWidget *parent)    {  }
    protected:
        void paintEvent(QPaintEvent*) 
        {
            QPainter realPainter(this);
            realPainter.drawPixmap(0,0,QPixmap("./01.png"));
        }
    };



    class Widget : public QScrollArea{
    public:
       Widget(QWidget *parent=0)
        {
            w_ = new QWidget(this);
            w_->resize(3000,3000);
           setWidget(w_);
        }
    protected:
        void paintEvent(QPaintEvent*)
        {
            QPainter realPainter(w_);
            realPainter.drawPixmap(0,0,QPixmap("./01.png"));
        }
    private:
        QWidget *w_;
    };

int main(int argc ,char *argv[])
{
    QApplication app(argc,argv);
    Widget w;
    w.show(); //the picture not paint out!!!
    ////////////////////////////
    //the code blow works ,I was wondering why?:confused:
    //Widget2 w;
    //w.show(); //the picture not paint out!!!
    /////////////////////////
 
    app.exec();


}

To copy to clipboard, switch view to plain text mode 

Any ideas about it ?
Thanks advance for your help
Best regards,
hb