QTreeView resize section to content but keep interactive

Joel Bodenmann

I'm trying to figure out how to setup/configure a QTreeView so that I one or more section can be programmatically resized to fit the content while still giving the user the ability to resize the section interactively afterwards.

From the corresponding QHeaderView documentation:

QHeaderView::ResizeToContents
QHeaderView will automatically resize the section to its optimal size based on the contents of the entire column or row. The size cannot be changed by the user or programmatically.

QHeaderView::Interactive
The user can resize the section. The section can also be resized programmatically using resizeSection(). The section size defaults to defaultSectionSize. (See also cascadingSectionResizes.)

I'd basically like a mix of the two: First, resize to fit content programmatically and then allow the user to resize interactively. But this doesn't seem to be an option.
One "workaround" might be to use setDefaultSectionSize() as mentioned by the documentation of QHeaderView::Interactive. However, I couldn't find any clear indications of what the integer size property would represent. Surely it wouldn't be number of pixels. Most likely some DPI independent unit?
In any case, this would force me to manually calculate the width needed to fit contents into the corresponding section. In case of text this would require calculating the text size using QFontMetric.

Is there any better way of achieving what I am after? Am I missing something obvious or is this just a non-standard use-case?

Edit: Seems like QHeaderView::setDefaultSectionSize() wouldn't work either because I'd want to assign different sizes for each section.

Gojir4

Hi @Joel-Bodenmann,

I think you can probably call void QHeaderView::resizeSections(QHeaderView::ResizeMode mode) "manually", for example when the view is shown, and set the resize mode to interactive only.

Joel Bodenmann

@Gojir4 That worked well. I'm not sure how I could have missed this simple solution... Thank you a lot!