Save Position and Size of the Application Window and load it for the next time

developer_96

@raven-worx is it not possible with the destructor ? i mean its like a close event or not ?
@Christian-Ehrlicher yes i will thank you.

Christian Ehrlicher

@developer_96 said in Save Position and Size of the Application Window and load it for the next time:

i mean its like a close event or not ?

I wrote why it doesn't work...

developer_96

@Christian-Ehrlicher right i undestand it know. And to solve the problem it would be ok to use my code in a close event ? and the part in the constructor is that ok ? I mean use it know in

void MainWindow::closeEvent(QCloseEvent* event)
{
  QSettings settings("MyCompany", "MyApp");
  settings.setValue("geometry", saveGeometry());
  settings.setValue("windowState", saveState());
  QMainWindow::closeEvent(event);
}

and the reload in my constructor.
But it doesn't work

artwaw

@developer_96 Hi,
of course it doesn't work. You save values as geometry and windowState but - looking at your previous code - load myWidget/geometry and myWidget/windowState.
In that notation loader expects a group, so sanitise your code please.

Two remarks:

if you use groups it might be more convenient to add settings.beginGroup("myWidget") before you start to read/write and settings.endGroup() once you done that part.
you init settings with "MyCompany" etc - it might be more convenient to put those in your main.cpp file once before QApplication init and not bother afterwards, like this:

    QCoreApplication::setApplicationVersion("Optional version string here");
    QCoreApplication::setOrganizationName("MyCompany");
    QCoreApplication::setOrganizationDomain("can be omitted on windows");
    QCoreApplication::setApplicationName("MyApp");
    QApplication a(argc, argv);

(editions: removed typos)
Cheers,
A.

developer_96

@artwaw hi,
thank you very much now its work. One problem is still remaining:
If i change the position its working.
If i do a fullscreen its still working.
But if I'm going to resize manually the application windows it does'nt work.
After close and reload i got the same size.
Maybe you can help me :)

artwaw

@developer_96 Odd. It should work, I use similar code in almost every project and it doesn't matter how you resize, it works.
From what you say though it looks like state is applied properly, the geometry is not (as maximised window is a state thing, not size).
If you're sure there is no typo between save and load of geometry I'd suggest clearing the settings (on Windows this involves registry, so please be careful) and trying again.
Also, you can try to put qDebug() on save and load to verify what is saved and loaded.
In closeEvent(): qDebug() << saveGeometry();
In ctor: qDebug() << settings.value("your geometry key").toByteArray();

developer_96

@artwaw
so there is no typo. I'm sure.
Constructor:

QSettings settings("MyCompany", "MyApp");
restoreGeometry(settings.value("geometry").toByteArray());
restoreState(settings.value("windowState").toByteArray());

Close Event:

QSettings settings("MyCompany", "MyApp");
settings.setValue("geometry", saveGeometry());
settings.setValue("windowState", saveState());
QMainWindow::closeEvent(event);

What you mean with settings ? Would this solve my problem ?

artwaw

@developer_96
qDebug() will output the data to the console so you can compare them - it might give you a hint what's wrong.

I would modify closeEvent() though:

QSettings settings("MyCompany", "MyApp");
settings.setValue("geometry", saveGeometry());
settings.setValue("windowState", saveState());
settings.sync(); // forces to write the settings to storage
event->accept();

And try again.

developer_96

@artwaw tried again. Not working. With debug() after close i got some hexa values. If im loading it, i got nothing. So "" is the only output.

Christian Ehrlicher

@developer_96 said in Save Position and Size of the Application Window and load it for the next time:

So "" is the only output.

This means you load the data from the wrong location. Fix your settings as @artwaw already told you (and not only here in the forum)

artwaw

@developer_96 like @Christian-Ehrlicher said, loader returns empty string which means data is being read from different location.
I'd strongly suggest editing main.cpp file like I hinted. Afterwards you just use QSettings settings;.

developer_96

@artwaw @Christian-Ehrlicher i did it already. Modify the cpp like @artwaw said. It doesn't work. I mean if it would be a wrong location the fullscreen mode and the position mode wouldn't work too , or not ?

Regards

Christian Ehrlicher

When the settings object returns an empty QByteArray but you saved a non-empty one you have a typo somewhere. Esp. when the same works for windowState. Check your code!

developer_96

How can i check that it works for windowsState? I mean i commented out the windows state part and the fullscreen and positing changing is still working. If im going to commented out the geometry nothing is working.

@Christian-Ehrlicher Check more times there is no typo.

Hope you can help.

Christian Ehrlicher

Provide a minimal, compilable example.

artwaw

@developer_96 you can use qDebug() to output saved and loaded values to the console, then compare them visually.

developer_96

@Christian-Ehrlicher

main.cpp:

  QCoreApplication::setOrganizationName("MyCompany");
  QCoreApplication::setApplicationName("MyApp");
  QApplication oApp(arc, arv);

close event:

  QSettings settings("MyCompany", "MyApp");
  settings.setValue("geometry", saveGeometry());
  settings.setValue("windowState", saveState());
  settings.sync(); // forces to write the settings to storage
  event->accept();
qDebug() << saveGeometry();
  qDebug() << saveState();

constructor:

  QSettings settings("MyCompany", "MyApp");
  restoreGeometry(settings.value("geometry").toByteArray());
  restoreState(settings.value("windowState").toByteArray());
  qDebug() << settings.value("geometry").toByteArray();
  qDebug() << settings.value("windowState").toByteArray();

@artwaw i tried again with debug.
I got for geometry values, compared windows stats and geomtry. Same values in save and loaded.

artwaw

@developer_96 Please change QSettings invocation from QSettings settings("MyCompany", "MyApp"); to QSettings settings; in ctor and closeEvent()
if you have same values on save and load then this should work. I am out of ideas for now.

developer_96

oki i will try it and tell you.
Another question:
How it would work for a qwidget for example?

  settings.setValue("qwidgetclassname/geometry", saveGeometry());
  restoreGeometry(settings.value("qwidgetclassname/geometry").toByteArray());
``
Maybe like that ??

artwaw

@developer_96 for particular widget it doesn't matter how you name it, string can be anything as long as it's unique. You can group it, you can save series as arrays, QSettings is really powerful.
But if you think of saving and restoring particular widgets let me tell you, there is really only a few cases when you need to do that. Qt way is to put your widgets into layouts on the window class and let Qt figure out sizes and positions once you restore global settings and state.
What's worth saving is for example when you have widgets placed on QSplitter - then it's worth saving splitter params.
Or sizes of sections of the header in views, should you want to.

Saving and restoring every widget's state etc is counter productive, using layouts is the right way.