Qt使用QGraphicsView实现滑动窗体效果

 源码已上传至CSDN，http://download.csdn.net/source/2808505

 

QGraphicsView用来显示一个滚动视图区的QGraphicsScene内容。QGraphicsScene提供了QGraphicsItem的容器功能。通常与QGraphicsView一起使用来描述可视化图形项目。

 

QGraphicsScene提供了一个视图的场景，通过在这样一个场景之上加入不同的QGraphicsItem来构建视图。而QGraphicsView则提供了一个widget来显示QGraphicsScene的内容。所以要想成功构建一个视图，这三个元素缺一不可。

 

以下是一个QGraphicsView的例子，实现滑动的窗体效果，工具栏和图片均为场景中的Item。

 

 

 

 

#include <QtCore>
#include <QtGui>
#include <QtSvg>
/*程序中用到了svg格式的图片，所以需包含QtSvg*/
#define PAGE_COUNT 5
/*定义滑动窗体的窗体数*/

 

 

 

定义工具栏，NviBar继承自QGraphicsRectItem，用法与QGraphicsItem类似。

 

class NaviBar : public QObject, public QGraphicsRectItem
{
    Q_OBJECT
public:
    NaviBar();
    void setPageOffset(qreal ofs);
signals:
    void pageSelected(int page);
protected:
    void mousePressEvent(QGraphicsSceneMouseEvent *event);
    void paint(QPainter *painter, const QStyleOptionGraphicsItem *option, QWidget *widget = 0);
private:
    QList<QGraphicsSvgItem*> m_icons;
    QGraphicsRectItem *m_cursor;
};

 

 

 

函数实现

 

#define ICON_SIZE 50
#define ICON_PAD 4
NaviBar::NaviBar()
        : QGraphicsRectItem()
{
    setRect(0, 0, 5 * ICON_SIZE, ICON_SIZE);
    setPen(Qt::NoPen);
    QStringList names;
    names << "map" << "web" << "home" << "weather" << "contacts";
    for (int i = 0; i < names.count(); ++i) {
        QString fname = names[i];
        fname.prepend(":/icons/");
        fname.append("-page.svg");
        QGraphicsSvgItem *icon = new QGraphicsSvgItem(fname);
        icon->setParentItem(this);
        const int dim = ICON_SIZE - ICON_PAD * 2;
        qreal sw = dim / icon->boundingRect().width();
        qreal sh = dim / icon->boundingRect().height();
        icon->setTransform(QTransform().scale(sw, sh));
        icon->setZValue(2);
        m_icons << icon;
    }
    m_cursor = new QGraphicsRectItem;
    m_cursor->setParentItem(this);
    m_cursor->setRect(0, 0, ICON_SIZE, ICON_SIZE);
    m_cursor->setZValue(1);
    m_cursor->setPen(Qt::NoPen);
    m_cursor->setBrush(QColor(Qt::white));
    m_cursor->setOpacity(0.6);
}
void NaviBar::setPageOffset(qreal ofs)
{
    m_cursor->setPos(ofs * ICON_SIZE, 0);
    for (int i = 0; i < m_icons.count(); ++i) {
        int y = (i == static_cast<int>(ofs + 0.5)) ? ICON_PAD : ICON_PAD * 2;
        m_icons[i]->setPos(i * ICON_SIZE + ICON_PAD, y);
        m_icons[i]->setOpacity(1);
    }
}
void NaviBar::mousePressEvent(QGraphicsSceneMouseEvent *event)
{
    emit pageSelected(static_cast<int>(event->pos().x() / ICON_SIZE));
}
void NaviBar::paint(QPainter * painter, const QStyleOptionGraphicsItem *option, QWidget *widget)
{
    painter->setBrush(Qt::white);
    painter->setOpacity(0.2);
    painter->drawRect(option->rect.adjusted(-20, ICON_PAD, 20, 0));
}

 

 

 

 

定义视图

 

class ParallaxHome: public QGraphicsView
{

};

 

 

 

main函数

 

#include "parallaxhome.moc"
int main(int argc, char *argv[])
{
    QApplication app(argc, argv);
    ParallaxHome w;
    w.resize(360, 640);
    w.show();
    return app.exec();
}

 

 

 

效果图

本文来源：http://blog.csdn.net/huihui1988/article/details/5725955