Widget Box

There is something called the Widget Box in the Qt Designer. It contains a list of widgets separated by categories. Each category button can be clicked in order to expand and collapse the list below the button.

You might want something like the Widget Box for one reason or another, to display your own collapsible list of items.

Tree Widget

In my approach in recreating the Widget Box I used a Tree Widget because it already has the basic idea of expanding and collapsing items in the list to display and hide its child widgets. The gist of turning the Tree Widget into a Widget Box is adding buttons as top level items and adding a frame with a layout as the child of those top level items. The button should then expand and collapse its own Tree Widget Item when clicked to display and hide the contents of a category. The button will require a custom class inheriting the QPushButton class in order to expand and collapse the Tree Widget Items.

You might want to disable root decoration and set indentation to 0 on the Tree Widget to turn it into a flat list. The custom button type is named QtCategoryButton in this snippet.

MyApplication::MyApplication(QWidget *parent, Qt::WFlags flags)
	: QMainWindow(parent, flags)
{
	ui.setupUi(this);

	ui.treeWidget->setRootIsDecorated(false);
	ui.treeWidget->setIndentation(0);

	// First category
	{
		QTreeWidgetItem* pCategory = new QTreeWidgetItem();
		ui.treeWidget->addTopLevelItem(pCategory);
		ui.treeWidget->setItemWidget(pCategory, 0,
			new QtCategoryButton("Category 1", ui.treeWidget, pCategory));

		QFrame* pFrame = new QFrame(ui.treeWidget);
		QBoxLayout* pLayout = new QVBoxLayout(pFrame);
		pLayout->addWidget(new QPushButton("Btn1"));
		pLayout->addWidget(new QPushButton("Btn2"));

		QTreeWidgetItem* pContainer = new QTreeWidgetItem();
		pContainer->setDisabled(true);
		pCategory->addChild(pContainer);
		ui.treeWidget->setItemWidget(pContainer, 0, pFrame);
	}

	// Second category
	{
		QTreeWidgetItem* pCategory = new QTreeWidgetItem();
		ui.treeWidget->addTopLevelItem(pCategory);
		ui.treeWidget->setItemWidget(pCategory, 0,
			new QtCategoryButton("Category 2", ui.treeWidget, pCategory));

		QFrame* pFrame = new QFrame(ui.treeWidget);
		QBoxLayout* pLayout = new QHBoxLayout(pFrame);
		pLayout->addWidget(new QPushButton("Btn1"));
		pLayout->addWidget(new QPushButton("Btn2"));

		QTreeWidgetItem* pContainer = new QTreeWidgetItem();
		pContainer->setDisabled(true);
		pCategory->addChild(pContainer);
		ui.treeWidget->setItemWidget(pContainer, 0, pFrame);
	}
}

Custom button

The custom button is a quite simple class, all it does it catch the pressed() signal and expands or collapses the Tree Widget Item it is bound to.

class QtCategoryButton : public QPushButton
{
	Q_OBJECT
public:
	QtCategoryButton(const QString& a_Text, QTreeWidget* a_pParent,
		QTreeWidgetItem* a_pItem);

private slots:
	void ButtonPressed();

private:
	QTreeWidgetItem* m_pItem;
};

 

QtCategoryButton::QtCategoryButton( const QString& a_Text,
		QTreeWidget* a_pParent, QTreeWidgetItem* a_pItem )
	: QPushButton(a_Text, a_pParent)
	, m_pItem(a_pItem)
{
	connect(this, SIGNAL(pressed()), this, SLOT(ButtonPressed()));
}

void QtCategoryButton::ButtonPressed()
{
	m_pItem->setExpanded( !m_pItem->isExpanded() );
}

Finally

If everything went well you should get something like this. You can of course use any other widgets, not just buttons.