Qt6 QProxyStyle cause app crash

Christian Ehrlicher

When you delete the style you also delete the base style as explained in the documentation (not Qt6 related):

Sets the base style that should be proxied.
Ownership of style is transferred to QProxyStyle.

Therefore create a new base style instead using the QApplication default one.

Dariusz

Hey

Ok still fighting with this...

I can set a QStyle() on QProxyStyle, but how can I then set QPalette on it & styleSheet?

I tried with >

        s = QStyleFactory.create("fusion")
        s.polish(m.getPalette()) 
        s.setStyleShet(""" data""") ?????
        self.setBaseStyle(s)

Any ideas?

TIA

The problem I'm having is that I can't get it to look the same as when I take QApplication::style().

Christian Ehrlicher

@Dariusz said in Qt6 QProxyStyle cause app crash:

The problem I'm having is that I can't get it to look the same as when I take QApplication::style().

Maybe your app isn't using the fusion style? Use the correct style which you app is using. The name of the style can only be retrieved via QApplication::style()->objectName() till Qt6.0, for 6.1 you can use a better function - QStyle::name() - see https://codereview.qt-project.org/c/qt/qtbase/+/328116

Dariusz

@Christian-Ehrlicher Yeah I do

In general I do something like this

app.setStyle(QStyleFactory.create("fusion"))
QPalette pa
/*pa set bunch of pa options */
app.setPalette(pa)
app.setStyleSheet(""" style stuff""")

But the QProxyStyle sheet does not properly clone it. So I'm trying to manually make a new one, assign it and well not cause any mem error... So far I'm failing left and right.

Christian Ehrlicher

When you create a new style you also have to apply your own palette if you want to same as the app style.

Dariusz

@Christian-Ehrlicher said in Qt6 QProxyStyle cause app crash:

When you create a new style you also have to apply your own palette if you want to same as the app style.

Yes but I can't get it to work.
I apply QStyle, Palette and StyleSheet to my QApp. But how can I properly replicate it ? I tried making a widget and then taking it from widget. But that did not work either. And QProxyStyle wrecks havoc when it gets a style each time.

Christian Ehrlicher

@Dariusz said in Qt6 QProxyStyle cause app crash:

But how can I properly replicate it ?

Apply the same things to the newly created style.

Dariusz

@Christian-Ehrlicher said in Qt6 QProxyStyle cause app crash:

@Dariusz said in Qt6 QProxyStyle cause app crash:

But how can I properly replicate it ?

Apply the same things to the newly created style.

I can't set styleSheet() on style... So I cant style the Style... o.o

Christian Ehrlicher

Then don't use this approach and don't delete the proxy style.

Dariusz

@Christian-Ehrlicher So I will have memory leak... I have to delete treeview when user changes properties...

Christian Ehrlicher

But why do you have to re-create the style then? Apart from that - why do you need to re-create a treeview widget at all?

Dariusz

@Christian-Ehrlicher The app creates content depending on user selection. Different content require different views as well as I can have multiple views for one content... so widgets gets made/deleted on a "normal basis". So deleting widget/treeView is a normal thing. It seems that this issue is even bigger on older OS as win7 just refuses to draw app after these "workarounds" :- (

Christian Ehrlicher

Sorry but I still don't see why you need to delete and re-create the proxy style. But do what you like.