What is the format of the data saved by QMainWindow::saveState()?

mayaknife

I have a bug in my app which comes down to two different window state files: one works while the other causes my app to crash. I'd like to be able to dump the contents of the two state files in human readable form so that I can compare them to see what's different. What is the format of the data saved by QMainWindowState()?

Thanks.

BreakBad

Doesn't it use "QSettings":http://qt-project.org/doc/qt-4.8/qsettings.html#details ? So it would depend on platform

Also may be worth mentioning: I just read you need to setObjectName for each toolbar and dockwidget for saveState to work (Qt 5). Perhaps you're not doing that in one of your instances?

mayaknife

My object names are fine.

saveState() returns a QByteArray. I tried casting the result of its data() method to QSettings but that didn't work. So now I'm picking my way through a binary dumpt of the data, trying to figure out its structure.

JKSH

Hi,

It's a custom binary format. You can examine the source code here to see how the byte stream is constructed: http://code.woboq.org/qt5/qtbase/src/widgets/widgets/qmainwindow.cpp.html#_ZNK11QMainWindow9saveStateEi

The code browser is interactive. Click on the functions to jump to their definitions. (You will eventually find QToolBarAreaLayout::saveState() and QDockAreaLayout::saveState() which do the writing. These are internal classes, so they are undocumented)