tdf#130857 qt weld: Implement QtInstanceAssistant::set_page_index HEADmaster

As already mentioned in

Change-Id: I91b44da40736f6e61c64167d00305a1d7ba06b45
Author: Michael Weghorn <m.weghorn@posteo.de>
Date:   Sat Feb 22 18:30:30 2025 +0100

tdf#130857 qt weld: Introduce QtInstanceAssistant

, the page id that QWizard uses does not conceptually match
the page index that weld::Assistant uses:

weld::Assistant uses two ways to refer to specific pages:
1) an int page index
2) an OUString identifier

QWizard uses an int id to refer to pages. This concept of an id does
not match the index concept that weld::Assistang uses. (The id generally
does not match an index in the range between 0 and the number of pages - 1.)

Introduce a new property PROPERTY_PAGE_INDEX that
gets set on the QWizardPage objects and contains
the page index as used in the weld::Assistant API
and 2 helper methods QtInstanceAssistant::pageIndex
and QtInstanceAssistant::setPageIndex to get/set
the page index property for a page as well as a helper
method QtInstanceAssistant::page that returns the
page for a given page index.

Update existing code to no longer assume that
the QWizard page ID and the weld::Assistant page index
are the same.

Implement QtInstanceAssistant::set_page_index that
moves an existing page to a new position/index.
Given that the IDs used in QWizard don't match the
page indices, use a vector to sort by page index
instead and reassign the new index property to
all pages at the end.

In a previous attempt trying to keep the QWizard page ID
and the weld::Assistant page index in sync, I ran
into the problem that the ID for a page cannot simply
be changed, and removing and reinserting a page with
a new ID had the side-effect that it triggered events.
(And the current page can change when pages are removed
from QWizard.)

While the default QWizard logic that decides what
page to switch to when pressing e.g. the "Next"
button would switch to the page with the lowest
ID greater than the current page (see [1], [2])
in which case the page IDs would be relevant.
However, the approach taken in LO is that the
logic of switching pages is handled "manually"
inside LO instead, using callbacks that get triggered
on button click, etc.

[1] https://doc.qt.io/qt-6/qwizard.html#nextId
[2] https://doc.qt.io/qt-6/qwizardpage.html#nextId

Change-Id: Idd94676e850cabca75763645cb1e102999b80b64
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/182047
Reviewed-by: Michael Weghorn <m.weghorn@posteo.de>
Tested-by: Jenkins

0 files changed, 0 insertions, 0 deletions