restoreDockWidget reports true - but doesn't restore

[Musmuris]

Hi,
I have a QMainWindow and saving the state as per the docs (saveSate and restoreState - and geometry). The docks all have unique objectName set. The are added after the constructor is called - but before the app gets going (i.e. before .exec())

The readSettings is called in the c'tor of my main window (again copied from the docs and then when a dock is added restoreDockWidget is called and returns true for each dock. However it just seems to do nothing - and the state is as they were. i.e. if I move them round, exit and restart, then they are back where were originally.

The ini file seems to be created (and updated) each time - state is obviously an opaque byte array (though it does have the dock names if one coverts to ascii!)

// aDock is created and object name set then passed to QMainWindow:
aDock->setAllowedAreas(Qt::AllDockWidgetAreas);
aDock->setAttribute(Qt::WA_DeleteOnClose, false);

auto act = aDock->toggleViewAction();
act->setIcon(icon);
displaysToolBar->addAction(act);

addDockWidget(Qt::TopDockWidgetArea, aDock);
restoreDockWidget(aDock)

Is the above expected to work?

[Musmuris]

And it turns out I was calling windows Show before adding the docks :facepalm:

For those following at home - the above code minus the readSettings in the main window c'tor then add

    void showEvent(QShowEvent* event) override
    {
        readSettings();
        QMainWindow::showEvent(event);
    }

[JonB]

@Musmuris
I think so, though I haven't used it. A while ago I think there were posts about dock area restoration issues, and maybe some work done on it. So you should probably state your exact Qt version and platform.

[SGaist]

Hi,

Can you provide a minimal example ?
The order of the operation you wrote are not clear.
To me it seems you are loading your settings too early with regard to how you construct your objects.

[Musmuris]

Sure - this is the essence of it:

#include <QtWidgets>


class MyDock: public QDockWidget
{
public:
    MyDock(const QString& title, const Qt::WindowFlags& flags = Qt::WindowFlags())
        : QDockWidget(title, nullptr, flags)
    {
        setWidget(new QLabel("test"));
    }

    ~MyDock() override = default;
};

class MyDockWindow : public QMainWindow
{
    //Q_OBJECT

public:
    MyDockWindow()
    {
        m_docksToolBar = addToolBar("docks");
        addToolBar(Qt::LeftToolBarArea, m_docksToolBar);
        m_docksToolBar->setIconSize(QSize(40, 40));
        m_docksToolBar->setMovable(false);
        m_docksToolBar->setFloatable(false);

        readSettings();
    }

    ~MyDockWindow() = default;

    void addDock(const QString& id, MyDock* myDock, const QIcon& icon)
    {
        myDock->setAllowedAreas(Qt::AllDockWidgetAreas);
        myDock->setAttribute(Qt::WA_DeleteOnClose, false);
        myDock->setObjectName(id);

        auto act = myDock->toggleViewAction();
        act->setIcon(icon);
        m_docksToolBar->addAction(act);

        addDockWidget(Qt::TopDockWidgetArea, myDock);
        //myDock->setVisible(false);
        qDebug("%s %d\n", id.toStdString().c_str(), restoreDockWidget(myDock));
    }


protected:
    void closeEvent(QCloseEvent* event) override
    {
        QSettings settings(QSettings::IniFormat, QSettings::UserScope, "dummy", "app");
        settings.setValue("geometry", saveGeometry());
        settings.setValue("windowState", saveState());
        QMainWindow::closeEvent(event);
    }

private:
    void readSettings()
    {
        QSettings settings(QSettings::IniFormat, QSettings::UserScope, "dummy", "app");
        restoreGeometry(settings.value("geometry").toByteArray());
        restoreState(settings.value("windowState").toByteArray());
    }

    QToolBar* m_docksToolBar;    
};

int main(int argc, char *argv[])
{
    QApplication a(argc, argv);
    MyDockWindow w;

    auto aDock = new MyDock("hello 1");
    w.addDock("hello1", aDock, QIcon::fromTheme(QIcon::ThemeIcon::Computer));
    aDock = new MyDock("hello 2");
    w.addDock("hello2", aDock, QIcon::fromTheme(QIcon::ThemeIcon::DriveOptical));

    w.show();
    return a.exec();
}

The docks available will be configurable in the main app - hence adding this way. I did also try restoring state when the window is shown (i.e. after all docks have been added).

EDIT: AH! Hang on - if I try restoring state in the showEvent on the mainwindow in the above test app then it works. Will just try that in the real one.

[Musmuris]

And it turns out I was calling windows Show before adding the docks :facepalm:

For those following at home - the above code minus the readSettings in the main window c'tor then add

    void showEvent(QShowEvent* event) override
    {
        readSettings();
        QMainWindow::showEvent(event);
    }

[SGaist]

It might not be the implementation you want, showEvent can be called several times through the lifetime of your application so your GUI will give your user surprises when maximizing from a minimized state for example.

I would recommend using a single shot QTimer with a 0 delay in your main.cpp to call readSettings.

[Musmuris]

Ah - good to know. Thanks - I can make sure it's a one shot