简单的锚点布局示例

演示了图形视图场景中的锚点布局。

“简单锚点布局”示例展示了QGraphicsAnchorLayout 类的基礎用法。

使用锚点布局放置控件的应用程序

该示例首先创建一个QGraphicsScene （scene ）、3个小部件（a 、b 和c ）以及一个QGraphicsAnchorLayout（layout ）。

    QGraphicsScene scene;

    Widget *a = new Widget(Qt::blue, Qt::white, "a");
    a->setPreferredSize(100, 100);
    Widget *b = new Widget(Qt::green, Qt::black, "b");
    b->setPreferredSize(100, 100);
    Widget *c = new Widget(Qt::red, Qt::black, "c");
    c->setPreferredSize(100, 100);

    QGraphicsAnchorLayout *layout = new QGraphicsAnchorLayout;

首先，将项a 的左上角锚定到layout 的左上角。这可以通过以下两个步骤实现：

    layout->addAnchor(a, Qt::AnchorTop, layout, Qt::AnchorTop);
    layout->addAnchor(a, Qt::AnchorLeft, layout, Qt::AnchorLeft);

或者通过一步完成：

    layout->addCornerAnchors(a, Qt::TopLeftCorner, layout, Qt::TopLeftCorner);

然后，将a 的右锚点锚定到b 的左锚点，并将项b 的顶部锚定到a 的底部。

    layout->addAnchor(b, Qt::AnchorLeft, a, Qt::AnchorRight);
    layout->addAnchor(b, Qt::AnchorTop, a, Qt::AnchorBottom);

在控件b 下方放置第三个控件c ：

    layout->addAnchor(b, Qt::AnchorBottom, c, Qt::AnchorTop);

元素b 和c 水平方向相互锚定：

    layout->addAnchors(b, c, Qt::Horizontal);

项目 c 锚定在layout

    layout->addCornerAnchors(c, Qt::BottomRightCorner, layout, Qt::BottomRightCorner);

最后，QGraphicsWidget w 在QGraphicsView view 中显示。

    auto w = new QGraphicsWidget(nullptr, Qt::Window | Qt::CustomizeWindowHint | Qt::WindowTitleHint);
    w->setPos(20, 20);
    w->setMinimumSize(100, 100);
    w->setPreferredSize(320, 240);
    w->setLayout(layout);
    w->setWindowTitle(QApplication::translate("simpleanchorlayout", "QGraphicsAnchorLayout in use"));
    scene.addItem(w);

    QGraphicsView view;
    view.setScene(&scene);
    view.setWindowTitle(QApplication::translate("simpleanchorlayout", "Simple Anchor Layout"));

    view.resize(360, 320);
    view.show();

    return app.exec();

示例项目 @ code.qt.io

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