2

如果我越过像QGraphicsRectItem.

我有一个继承自的类，QGraphicsView矩形显示在QGraphicScene.

我用eventFilter.

问题是当我已经点击矩形时光标会改变，而我希望它在我传递它时改变。我已经用 a 改变了光标QAbstractButton，但是QGraphicsRectItem::enterEvent(event)不起作用。

这是我的代码QAbstractButton：

void ToggleButton::enterEvent(QEvent *event) {
    setCursor(Qt::PointingHandCursor);
    QAbstractButton::enterEvent(event);
}

在这种情况下，它可以工作。

这是我的代码来检测我是否传递了一个矩形：

DetecRect::DetecRect(QWidget* parent) : 
    QGraphicsView(parent)
{
     scene = new QGraphicsScene(this);
     pixmapItem=new QGraphicsPixmapItem(pixmap);
     scene->addItem(pixmapItem);
     this->setScene(scene);
     this->setMouseTracking(true);
     scene->installEventFilter(this);
}

bool DetecRect::eventFilter(QObject *watched, QEvent *event)
{
    if(watched == scene){
        // press event
        QGraphicsSceneMouseEvent *mouseSceneEvent;
        if(event->type() == QEvent::GraphicsSceneMousePress){
            mouseSceneEvent = static_cast<QGraphicsSceneMouseEvent *>(event);
            if(mouseSceneEvent->button() & Qt::LeftButton){

            }
        // move event
        } else if (event->type() == QEvent::GraphicsSceneMouseMove) {
            mouseSceneEvent = static_cast<QGraphicsSceneMouseEvent *>(event);
             //selectedItem is a QGraphicsItem
            if(this->selectedItem && this->selectedItem->type() == QGraphicsRectItem::Type){
                selectedItem->setCursor(Qt::PointingHandCursor);
            }
        }
        // release event
        else if (event->type() == QEvent::GraphicsSceneMouseRelease) {
            mouseSceneEvent = static_cast<QGraphicsSceneMouseEvent *>(event);
        }
    }
    return QGraphicsView::eventFilter(watched, event);
}

在这段代码中，如果我单击一次，光标会发生变化。但是如果我直接通过就不要更改。为什么？

4

1 回答 1

2

您不必实现 hoverEnterEvent 方法或 hoverLeaveEvent，您只需将光标设置到项目，如下所示：

#include <QApplication>
#include <QGraphicsRectItem>
#include <QGraphicsView>

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);

    QGraphicsView view;
    QGraphicsScene *scene = new QGraphicsScene(&view);
    view.setScene(scene);

    QGraphicsRectItem *rit = scene->addRect(QRectF(-50, -50, 100, 100), QPen(Qt::black), QBrush(Qt::gray));
    rit->setCursor(Qt::CrossCursor);

    QGraphicsRectItem *rit2 = new QGraphicsRectItem(QRectF(-50, -50, 100, 100));
    rit2->setPen(QPen(Qt::white));
    rit2->setBrush(QBrush(Qt::green));
    rit2->setCursor(Qt::PointingHandCursor);
    rit2->setPos(200, 100);
    scene->addItem(rit2);

    view.resize(640, 480);
    view.show();
    return a.exec();
}
于 2018-07-13T11:54:59.463 回答