qt

1、设置qt widget全屏显示

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    MainWindow w;
    //w.show();
    w.showFullScreen();
    return a.exec();
}

int main(int argc, char *argv[]) { QApplication a(argc, argv); MainWindow w; //w.show(); w.showFullScreen(); return a.exec(); }
2、获取屏幕分辨率

#include <QDesktopWidget>
#Include <QApplication>
void MainWindow::GetScreenInfo()
{
    QDesktopWidget* desktopWidget = QApplication::desktop();
    //获取可用桌面大小
    //QRect deskRect = desktopWidget->availableGeometry();
    //获取设备屏幕大小
    QRect screenRect = desktopWidget->screenGeometry();

    sceenSizeX = screenRect.width();
    sceenSizeY = screenRect.height();

    //获取系统设置的屏幕个数（屏幕拷贝方式该值为1）
    //g_nScreenCount = desktopWidget->screenCount();
}

#include <QDesktopWidget> #Include <QApplication> void MainWindow::GetScreenInfo() { QDesktopWidget* desktopWidget = QApplication::desktop(); //获取可用桌面大小 //QRect deskRect = desktopWidget->availableGeometry(); //获取设备屏幕大小 QRect screenRect = desktopWidget->screenGeometry(); sceenSizeX = screenRect.width(); sceenSizeY = screenRect.height(); //获取系统设置的屏幕个数（屏幕拷贝方式该值为1） //g_nScreenCount = desktopWidget->screenCount(); }
3、QGraphicsView添加背景图片：1

view = new QGraphicsView;
scene = new QGraphicsScene(0,0,800,480);
QPixmap pixmap(":/gear.png");
scene->addPixmap(pixmap);
view->setScene(scene);

view = new QGraphicsView; scene = new QGraphicsScene(0,0,800,480); QPixmap pixmap(":/gear.png"); scene->addPixmap(pixmap); view->setScene(scene);
3、QGraphicsView添加背景图片：2

view->setBackgroundBrush(QImage(":/gear.png"));

view->setBackgroundBrush(QImage(":/gear.png"));前提是将gear.png加入到资源中

4、设置无边框（标题栏）的应用程序

QApplication a(argc, argv);
MainWindow w;

w.setWindowOpacity(1);
w.setWindowFlags(Qt::FramelessWindowHint);
w.setAttribute(Qt::WA_TranslucentBackground);
w.show();

QApplication a(argc, argv); MainWindow w; w.setWindowOpacity(1); w.setWindowFlags(Qt::FramelessWindowHint); w.setAttribute(Qt::WA_TranslucentBackground); w.show();

5 、QGraphicsPixmapItem，显示图片Item

scene = new QGraphicsScene(0,0,800,480);

QGraphicsPixmapItem *pixmapItem = new QGraphicsPixmapItem(QPixmap(":/gear.png"));
pixmapItem->setFlags(QGraphicsItem::ItemIsMovable | QGraphicsItem::ItemIsSelectable);
scene->addItem(pixmapItem);

scene = new QGraphicsScene(0,0,800,480); QGraphicsPixmapItem *pixmapItem = new QGraphicsPixmapItem(QPixmap(":/gear.png")); pixmapItem->setFlags(QGraphicsItem::ItemIsMovable | QGraphicsItem::ItemIsSelectable); scene->addItem(pixmapItem);

6 Q_OBJECT 问题

class NodeUI : public QGraphicsPixmapItem
{
    Q_OBJECT
...
}

class NodeUI : public QGraphicsPixmapItem { Q_OBJECT ... }编译不通过

class NodeUI : public QGraphicsPixmapItem ,public QObject
{
    Q_OBJECT
...
}

class NodeUI : public QGraphicsPixmapItem ,public QObject { Q_OBJECT ... }依然不通过

class NodeUI : public QObject,public QGraphicsPixmapItem
{
    Q_OBJECT
...
}

class NodeUI : public QObject,public QGraphicsPixmapItem { Q_OBJECT ... }编译通过！

7 ，编译出错：error: passing 'const QPointF' as 'this' argument of 'QPointF& QPointF::operator=(const QPointF&)' discards qualifiers

NodeUI *MainWindow::selectedNodeUI() const
{
    QList<QGraphicsItem *> items = scene->selectedItems();
    if (items.count() == 1) {
        mmyPos = items.first()->pos();
        //QPointF myPos = pos;
        //mmyPos = pos.toPoint();
        //mmyPos.setX(x);
        //mmyPos.setY(y);
        //mmyPos = QPoint(x,y);
        //qDebug()<<"items.x:"<<nodePos.x()<<"items.y:"<<nodePos.y();
        return dynamic_cast<NodeUI *>(items.first());
    } else {
        return 0;
    }
}

NodeUI *MainWindow::selectedNodeUI() const { QList<QGraphicsItem *> items = scene->selectedItems(); if (items.count() == 1) { mmyPos = items.first()->pos(); //QPointF myPos = pos; //mmyPos = pos.toPoint(); //mmyPos.setX(x); //mmyPos.setY(y); //mmyPos = QPoint(x,y); //qDebug()<<"items.x:"<<nodePos.x()<<"items.y:"<<nodePos.y(); return dynamic_cast<NodeUI *>(items.first()); } else { return 0; } }修改为如下，问题解决；

NodeUI *MainWindow::selectedNodeUI()
{
    QList<QGraphicsItem *> items = scene->selectedItems();
    if (items.count() == 1) {
        mmyPos = items.first()->pos();
        //QPointF myPos = pos;
        //mmyPos = pos.toPoint();
        //mmyPos.setX(x);
        //mmyPos.setY(y);
        //mmyPos = QPoint(x,y);
        //qDebug()<<"items.x:"<<nodePos.x()<<"items.y:"<<nodePos.y();
        return dynamic_cast<NodeUI *>(items.first());
    } else {
        return 0;
    }
}

本文转载自：http://blog.csdn.net/ghostyu/article/details/7002178