Question

I m 竭力争取加入QGraphicsLinearLayout,与QGraphicsScene合作这样一来,就会有一组<代码>。梯度项目以直线方式放在现场。我尝试采用以下方法:

#include <QApplication>
#include <QBrush>
#include <QGraphicsItem>
#include <QGraphicsLayoutItem>
#include <QGraphicsLinearLayout>
#include <QGraphicsRectItem>
#include <QGraphicsScene>
#include <QGraphicsView>
#include <QGraphicsWidget>
#include <QPen>

class MyShape : public QGraphicsRectItem, public QGraphicsLayoutItem {
  public:
    MyShape(void) {
        setPen(QPen(QBrush(Qt::black), 1));
        setBrush(QBrush(Qt::green));
        setRect(0, 0, 20, 20);
    }

    virtual QSizeF sizeHint(Qt::SizeHint which,
                            const QSizeF& constraint = QSizeF()) const {
        Q_UNUSED(which);
        Q_UNUSED(constraint);
        return boundingRect().size();
    }
};

int main(int argc, char** argv) {
    QApplication app(argc, argv);

    QGraphicsScene scene;
    MyShape* shape1 = new MyShape;
    MyShape* shape2 = new MyShape;
    MyShape* shape3 = new MyShape;
    scene.addItem(shape1);
    scene.addItem(shape2);
    scene.addItem(shape3);

    QGraphicsLinearLayout* layout = new QGraphicsLinearLayout;
    layout->addItem(shape1);
    layout->addItem(shape2);
    layout->addItem(shape3);

    QGraphicsWidget* container = new QGraphicsWidget;
    container->setLayout(layout);
    scene.addItem(container);

    QGraphicsView view;
    view.setScene(&scene);
    view.show();

    return app.exec();
}

由于所有项目仍相互搁置,而不是相互(根据线性布局的布局)。我做了什么错误?

Answer 1

Ah,我忘记凌驾于<条码>。

因此,实施<代码>MyShape类别就应如此:

class MyShape : public QGraphicsRectItem, public QGraphicsLayoutItem {
  public:
    MyShape(void) {
        setPen(QPen(QBrush(Qt::black), 1));
        setBrush(QBrush(Qt::green));
        setRect(0, 0, 20, 20);
    }

    virtual QSizeF sizeHint(Qt::SizeHint which,
                            const QSizeF& constraint = QSizeF()) const {
        Q_UNUSED(which);
        Q_UNUSED(constraint);
        return boundingRect().size();
    }

    virtual void setGeometry(const QRectF& rect) {
        setPos(rect.topLeft());
    }
};

http://www.un.org/Depts/DGACM/index_russian.htm

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