Scrollbars for QStackedLayout

Hello!

I have worked out a solution that works for me, but I would like to know, if I missed a more elegant solution.

I needed a widget, that shows a list of several possible user interfaces, that fit into a defined space. Therefore I put a StackedLayout into a Scrollarea.

First: A StackedLayout that has its minimumSize set depending only on the currentwidget and not all its child-widgets:

Code:

---

class CStackedLayout : public QStackedLayout
{  Q_OBJECT
public:
  explicit CStackedLayout(QWidget *parent = 0) : QStackedLayout(parent) {}
  QSize sizeHint() const
  {
    QWidget* cw = currentWidget();
    if (cw) return cw->sizeHint(); else return QSize(0,0);
  }
  QSize minimumSize() const
  {
    QWidget* cw = currentWidget();
    if (cw) return cw->minimumSize(); else return QSize(0,0);
  }
};

---

Based on that StackLayout I build a StackedWidget, that updates its minimumSize, if appropriate:

Code:

---

class CStackedWidget : public QFrame
{  Q_OBJECT
  Q_PROPERTY(int currentIndex READ currentIndex WRITE setCurrentIndex NOTIFY currentChanged)
  Q_PROPERTY(int count READ count)
public:
  explicit CStackedWidget(QWidget *parent=0) : QFrame(parent)
  {
    layout = new CStackedLayout(this);
    connect(layout, SIGNAL(widgetRemoved(int)), this, SIGNAL(widgetRemoved(int)));
   connect(layout, SIGNAL(currentChanged(int)), this, SLOT(updateConstraints()));
    connect(layout, SIGNAL(currentChanged(int)), this, SIGNAL(currentChanged(int)));
  }
 
  int addWidget(QWidget *w) {return layout->addWidget(w);}
  int insertWidget(int index, QWidget *w) {return layout->insertWidget(index, w);}
  void removeWidget(QWidget *w) {layout->removeWidget(w);}
 
  QWidget *currentWidget() const {return layout->currentWidget();}
  int currentIndex() const {return layout->currentIndex();}
 
  int indexOf(QWidget *w) const {return layout->indexOf(w);}
  QWidget *widget(int index) const {return layout->widget(index);}
  int count() const {return layout->count();}
 
public slots:
  void setCurrentIndex(int index) {layout->setCurrentIndex(index);}
  void setCurrentWidget(QWidget *w) {layout->setCurrentWidget(w);}
 
 void updateConstraints() {setMinimumSize(layout->minimumSize().width(),layout->minimumSize().height());resize(size());}
signals:
  void currentChanged(int);
  void widgetRemoved(int index);
 
private:
  CStackedLayout* layout;
};

---

And a multiwidget selector class, which shows a ListWidget from which you can choose the current widget of the stack.

Code:

---

class CMultiWidget : public QWidget
{  Q_OBJECT
public:
  CMultiWidget()
  {
    list = new QListWidget();
    list->setMinimumWidth(30);
    list->setMaximumWidth(100);
 
    wdgstack = new CStackedWidget();
    wdgstack->setContentsMargins(0,0,0,0);
 
    sa = new QScrollArea();
    sa->setWidgetResizable(true);
    sa->setWidget(wdgstack);
    sa->setContentsMargins(0,0,0,0);
    sa->setFrameStyle(QFrame::NoFrame);
 
    QHBoxLayout *layout = new QHBoxLayout();
 
    layout->addWidget(list,0);
    layout->addWidget(sa,1);
 
    setLayout(layout);
 
    connect(list,SIGNAL(currentRowChanged(int)),wdgstack,SLOT(setCurrentIndex(int)));
  }
public slots:
  void AddWidget(QString caption,QWidget* wdg)
  {
    wdgstack->addWidget(wdg);
    list->addItem(caption);
  }
private:
  QListWidget* list;
  CStackedWidget* wdgstack;
  QScrollArea* sa;
};

---

A small example:

Code:

---

class CContentWidget : public QWidget
{  Q_OBJECT
public:
  CContentWidget(int listcount,int w,int h)
  {
    setMinimumSize(w,h);
    QHBoxLayout* hl = new QHBoxLayout();
    for (int i = 0;i < listcount;++i)
    {
      hl->addWidget(new QListWidget());
    }
    setLayout(hl);
  }
private:
};
 
int main(int argc, char *argv[])
{
  QApplication a(argc, argv);
  CMultiWidget w;
  w.resize(600,300);
  w.AddWidget("A",new CContentWidget(2,250,150));
  w.AddWidget("B",new CContentWidget(3,250,500));
  w.show();
  return a.exec();
}

---

Thx in advance for any recommendations!

Johannes