QDialog::setGeometry() on Windows 10 / Linux

Robert Hairgrove

I have a QDialog with a single QComboBox which is displayed after selection of a popup menu option. It should look like a simple combo box, but with a window title bar, which is why I chose to embed it in a dialog. The dialog's accept() slot is connected to the combo box currentIndexChanged() signal, and the dialog also has the window attribute WA_DeleteOnClose.

On Linux and Windows, I create the dialog as follows:

void DlgGraphView::onProfessionSearch(bool)
{
  const QPoint pt = QCursor::pos();
  const QString title = tr("Find Profession:");

  DlgFramedComboBox *pfcb = new DlgFramedComboBox(title, true, this);

  if (pfcb) {
    pfcb->setAttribute(Qt::WA_DeleteOnClose);  // auto-delete after selection
    const QRect cr = QRect(pt, pfcb->minimumSize()); // get minimum rectangle
    initBerufeComboBox(pfcb); // fill in the items
    pfcb->setGeometry(cr); // should eliminate extra space around combobox
    pfcb->show();
    pfcb->setFocus();
  }
}

On Linux, this works as desired (see image below). However, on Windows, this opens much too large vertically. The dialog is made in Qt Designer and has the sizeHint property [Horizontal:]Preferred - [Vertical:]Fixed. The combo is contained in a grid layout of the dialog. I can manually resize the dialog once it is shown, but it shouldn't be necessary.

Screenshot of the way this opens on Windows:

Screenshot of the desired size:

How can I write the code so that the behavior is the same on Linux as on Windows?

Linux: Ubuntu 18.04 LTS running default window manager (Gtk) with Qt 5.15.5 built from source;

Windows: Windows 10, Qt 5.12.9 installed from binary offline installer.

Robert Hairgrove

@Robert-Hairgrove Here is the code for the class definition of DlgFramedComboBox as well as the implementation:

DlgFramedComboBox.hpp:

#ifndef DLGFRAMEDCOMBOBOX_H
#define DLGFRAMEDCOMBOBOX_H

#include "SbblGlobal.hpp"
#include "wrapQtWidgets.h"

namespace Ui {
class FramedComboBox;
}

namespace sbbl::gui::dialogs {
class DlgGraphView;

class DlgFramedComboBox : public QDialog
{
  Q_OBJECT

public:
  explicit DlgFramedComboBox(const QString &windowtitle,
                          bool prof_search,
                          QWidget *parent = nullptr);
  ~DlgFramedComboBox();

  void addItem(const QString &itemtext, const QVariant &value);
  bool isProfSearch() const { return is_prof_search_; }
  bool isStudentSearch() const { return !is_prof_search_; }

public slots:
  void on_comboBox_currentIndexChanged(int idx);

protected:
  void changeEvent(QEvent *e);

signals:
  void notifyProfSelected(int bnr);
  void notifySuSSelected(int bnr);

private:
  Ui::FramedComboBox *ui;
  DlgGraphView       *p_;
  const bool         is_prof_search_;
};

} // namespace sbbl::gui::dialogs

#endif // DLGFRAMEDCOMBOBOX_H

DlgFramedComboBox.cpp:

#include "gui/dialogs/DlgFramedComboBox.hpp"
#include "gui/dialogs/DlgGraphView.hpp"
#include "ui_FramedComboBox.h"

namespace sbbl::gui::dialogs {

static bool SLOTS_ACTIVE = false;

DlgFramedComboBox::DlgFramedComboBox(
        const QString &windowtitle,
        bool prof_search,
        QWidget *parent)
  : QDialog(parent)
  , ui(new Ui::FramedComboBox)
  , p_ (qobject_cast<dialogs::DlgGraphView*>(parent))
  , is_prof_search_(prof_search)
{
  using namespace dialogs;

  SLOTS_ACTIVE = false;
  ui->setupUi(this);

  setWindowTitle(windowtitle);
  setFocusPolicy(Qt::StrongFocus);

  if (p_) {
    if (prof_search) {
      connect(this, &DlgFramedComboBox::notifyProfSelected,
              p_, &DlgGraphView::gotProfSearch);
    } else {
      connect(this, &DlgFramedComboBox::notifySuSSelected,
              p_, &DlgGraphView::gotSuSSearch);
    }
  }
  SLOTS_ACTIVE = true;
}

DlgFramedComboBox::~DlgFramedComboBox()
{
  delete ui;
}

void DlgFramedComboBox::addItem(const QString &itemtext, const QVariant &value)
{
  SLOTS_ACTIVE = false;
  ui->comboBox->addItem(itemtext, value);
  SLOTS_ACTIVE = true;
}

void DlgFramedComboBox::on_comboBox_currentIndexChanged(int idx)
{
  if (!SLOTS_ACTIVE) return;

  int selected = -1;

  if (idx >= 0) {
    int the_data = ui->comboBox->currentData().toInt();
    if (the_data) {
      selected = the_data;
    }
  }

  if (is_prof_search_) {
    emit notifyProfSelected(selected);
  } else {
    emit notifySuSSelected(selected);
  }

  //---------------------------------------------
  // This will automatically delete the object
  // since the caller sets the 'WA_DeleteOnClose'
  // window attribute when it is created:
  //---------------------------------------------
  accept();
}

void DlgFramedComboBox::changeEvent(QEvent *e)
{
  QWidget::changeEvent(e);
  switch (e->type()) {
  case QEvent::LanguageChange:
    ui->retranslateUi(this);
    break;
  default:
    break;
  }
}

} // namespace sbbl::gui::dialogs

Pl45m4

@Robert-Hairgrove said in QDialog::setGeometry() on Windows 10 / Linux:

The combo is contained in a grid layout of the dialog

Why a grid if you dont plan to add more to that dialog?

const QRect cr = QRect(pt, pfcb->minimumSize()); // get minimum rectangle

Try something like (if you have the correct size set in QtDesigner)

pfcb->setFixedHeight(pfcb->sizeHint().height())

https://doc.qt.io/qt-6/qwidget.html#setFixedHeight

mpergand

@Robert-Hairgrove
Set the size after calling show()

pfcb->show();
pfcb->setFixedSize(pcfb->size());

Robert Hairgrove

@Pl45m4 and @mpergand : Thanks!

This was the solution -- a combination of both suggestions:

// as above, then:
pfcb->show();
pfcb->setFixedHeight(pfcb->minimumHeight());
// etc.