replacing layout on a QWidget with another layout

Question

I have a widget which changes when an option is toggled. This invalidates all layouts and widgets. I keep list of all layouts, so I can delete them using something similar t

Answer 1

You can simply reparent the layout to a temporary widget:

def reLayout(self):
    QWidget().setLayout(self.layout())
    layout = QGridLayout(self)
    ...

That will reparent all the child widgets to that temporary object, and that object is deleted immediately along with its new children because we don't keep a reference to it.

But the typical way to have multiple layouts for a single widget and to be able to switch between them is to use a QStackedWidget or QStackedLayout.

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And if you still need the answer to that secondary question:

How to delete the old layout first?

It seems you can't delete directly a QObject which has a parent, because the parent is keeping a reference to that object. But you can add the object to a temporary QObjectCleanupHandler which, like the above solution, will be deleted with the object(s) it contains immediately:

QObjectCleanupHandler().add(self.layout())