qt4.8.4 QWidget se mueve con el mouse y establece el fondo

#ifndef SETTINGWGT_H
#define SETTINGWGT_H

#include <QWidget>
#include "ui_settingwgt.h"
#include <QPainter>
#include <QMouseEvent>

class SettingWgt : public QWidget
{
Q_OBJECT
señala:
void SendClose();
espacios privados:
void sltOn_Enter();
vacío sltOn_Close();
público:
SettingWgt(QWidget *padre = 0);
~ConfiguraciónWgt();
protegido:
void paintEvent (QPaintEvent * evento);
void mousePressEvent(QMouseEvent*);
void mouseReleaseEvent(QMouseEvent*);
void mouseMoveEvent(QMouseEvent*);
privado:
Ui::SettingWgt ui;
QPixmap * m_pQPixmapBg;
QPoint mover_punto;
bool mouse_press;
};

#endif // SETTINGWGT_H

#include "settingwgt.h"

这里写代码片

SettingWgt::SettingWgt(QWidget *parent)
    : QWidget(parent)
{
    ui.setupUi(this);
    setWindowFlags(/*Qt::WindowStaysOnTopHint |*/ Qt::FramelessWindowHint |  Qt::WindowSystemMenuHint | Qt::WindowMinMaxButtonsHint | Qt::Dialog);
    m_pQPixmapBg = new QPixmap("Resources/widbox");
    mouse_press = false;
    connect(ui.pushButton_close, SIGNAL(clicked()), this, SLOT(void sltOn_Close()));
    connect(ui.pushButton_enter, SIGNAL(clicked()), this, SLOT(sltOn_Enter()));

}

SettingWgt::~SettingWgt()
{

}
void SettingWgt::sltOn_Close()
{
    close();
    emit SendClose();
}
void SettingWgt::sltOn_Enter()
{
    close();
    emit SendClose();
}
void SettingWgt::paintEvent(QPaintEvent *event) {

    QPainter painter(this);
    painter.drawPixmap(m_pQPixmapBg->rect(), *m_pQPixmapBg);
}

void SettingWgt::mousePressEvent(QMouseEvent * pQMouseEvent )
{
    switch(pQMouseEvent->button()) {
    case Qt::LeftButton:
        mouse_press = true;
        break;

    default:
        break;
    }

    move_point = pQMouseEvent->globalPos() - pos();
}
void SettingWgt::mouseReleaseEvent(QMouseEvent* pQMouseEvent)
{
    mouse_press = false;
}
void SettingWgt::mouseMoveEvent(QMouseEvent* pQMouseEvent)
{
    if(mouse_press) {
        QPoint move_pos = pQMouseEvent->globalPos();
        move(move_pos - move_point);
    }
}