Custom Widget in QListWidgetItem in QListWidget, QListWidgetItem doesn't resize

[TestCoder]

Hello,
i have a simple custom widget multiple times in a QListWidget.
The custom widget contain some buttons and other suff and a QTableView,
whitch is hidden in the first place.

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The button "Show/Hide TableView" will toggle the visibility of the QTableView.
But when the visibility is set to true, the widget doesn't resize.
In the next picture i clicked once the button "Show/Hide TableView" and the
QTableView will be visible (small white bar), but the surrounding QGroupBox
doens't change it's size and therefore also not the QListWidgetItem.

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What i need:
- a widget based list view (i have used QListWidget)
- custom widgets which may change in size (e.g by setting the visibility of childs)

Can anyone help why my example doesn't work? (see Zip file)

Thx
Stefan

[ChrisW67]

The first part of the problem is to get TestWidget to resize itself properly in isolation. The secret to this is the QLayout::SetFixedSize size constraint on the top-level layout of the TestWidget.
See the Extension Example (https://doc.qt.io/qt-5/qtwidgets-dialogs-extension-example.html)

The second part of the problem is to have the list view resize its rows when one of the child widgets changes size (up or down). I do not have an obvious way to do this off the top of my head. It will resize rows if the QListWidget itself is resized, but that would be a nasty hack. Calling update() on the QListWidget when the child widget resizeEvent() is called does work either.

You may need to make your own "list" out of a QScrollArea, QWidget, and QVBoxLayout to gain the control you need.