Border Layout Example▲

Border Layout implements a layout that arranges child widgets to surround the main area.

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The constructor of the Window class creates a QTextBrowser object, to which a BorderLayout named layout is added. The declaration of the BorderLayout class is quoted at the end of this document.

 
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Window::Window()
{
    QTextBrowser *centralWidget = new QTextBrowser;
    centralWidget->setPlainText(tr("Central widget"));

    BorderLayout *layout = new BorderLayout;

Several labeled widgets are added to layout with the orientation Center, North, West, East 1, East 2, and South.

 
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    layout->addWidget(centralWidget, BorderLayout::Center);
    layout->addWidget(createLabel("North"), BorderLayout::North);
    layout->addWidget(createLabel("West"), BorderLayout::West);
    layout->addWidget(createLabel("East 1"), BorderLayout::East);
    layout->addWidget(createLabel("East 2") , BorderLayout::East);
    layout->addWidget(createLabel("South"), BorderLayout::South);
    setLayout(layout);

    setWindowTitle(tr("Border Layout"));

createLabel() in class Window sets the text of the labeled widgets and the style.

 
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QLabel *Window::createLabel(const QString &text)
{
    QLabel *label = new QLabel(text);
    label->setFrameStyle(QFrame::Box | QFrame::Raised);
    return label;
}

Class BorderLayout contains all the utilitarian functions for formatting the widgets it contains.

 
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class BorderLayout : public QLayout
{
public:
    enum Position { West, North, South, East, Center };

    explicit BorderLayout(QWidget *parent, int margin = 0, int spacing = -1);
    BorderLayout(int spacing = -1);
    ~BorderLayout();

    void addItem(QLayoutItem *item) override;
    void addWidget(QWidget *widget, Position position);
    Qt::Orientations expandingDirections() const override;
    bool hasHeightForWidth() const override;
    int count() const override;
    QLayoutItem *itemAt(int index) const override;
    QSize minimumSize() const override;
    void setGeometry(const QRect &rect) override;
    QSize sizeHint() const override;
    QLayoutItem *takeAt(int index) override;

    void add(QLayoutItem *item, Position position);

private:
    struct ItemWrapper
    {
        ItemWrapper(QLayoutItem *i, Position p) {
            item = i;
            position = p;
        }

        QLayoutItem *item;
        Position position;
    };

    enum SizeType { MinimumSize, SizeHint };
    QSize calculateSize(SizeType sizeType) const;

    QList<ItemWrapper *> list;
};

For more information, visit the Layout Management page.

Running the Example▲

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