[Qt-interest] small QDataWidgetMapper/QSelectionModel annoyance

[Israel Brewster]

Turns out I was wrong - it wasn't the show command, at least not  
directly. What it was was that the QlistView gained focus when the  
window was activated, causing the selection model to be updated with  
the new index. Changing the tab order so the QListView was no longer  
first fixed the issue. Sorry about the bother.
-----------------------------------------------
Israel Brewster
Computer Support Technician
Frontier Flying Service Inc.
5245 Airport Industrial Rd
Fairbanks, AK 99709
(907) 450-7250 x293
-----------------------------------------------


On Mar 3, 2009, at 10:36 AM, Israel Brewster wrote:

> I have an interface set up with two panes: a QListView on one side,
> and a QTextEdit on the other. I am using a QDataWidgetMapper to map a
> Model field to the QTextEdit, the QListView simply displays one of the
> model columns (same model). In order to update the QDataWidgetMapper
> (and, thus, the QTextEdit) when an item in the QListView is chosen, I
> have the following code:
>
> QItemSelectionModel *selectedNote=notesList->selectionModel();
> connect
> (selectedNote
> ,SIGNAL
> (currentChanged
> (QModelIndex
> ,QModelIndex)),&noteMapper,SLOT(setCurrentModelIndex(QModelIndex)));
>
> this all works properly (noteMapper is my QDataWidgetMapper). The
> problem I am running into is with the intial state. I want it to start
> up with nothing selected in the QListView, and the QTextEdit being
> empty (i.e. QDataWidgetMapper::currentIndex()==-1) So as the last line
> of my constructor I put in:
>
> selectedNote- 
> >setCurrentIndex(QModelIndex(),QItemSelectionModel::Clear);
>
> and then checked in the debugger that everything was populated as
> desired. This also worked. HOWEVER, upon the window being shown, I
> found the following:
>
> 1) nothing selected in the list view (good)
> 2) the QTextEdit populated with the first item (bad)
> 3) the QSelectionModel positioned with the current index being the
> first item of the QListView, as indicated by the fact the
> currentChanged signal is not emitted when clicking the first item in
> the QListView (bad)
>
> Number two and three would imply (to me at least) that somehow the
> currentChanged signal of the selectionModel was emitted AFTER the
> constructor ran, with the currentIndex being set to the first item in
> the QListView - probably when I called show(). This is not the
> behavior I want. How can I either a) prevent the signal from being
> emitted (if this is, in fact, what is going on) or b) reset everything
> as the final action? I suppose I could kludge the second option
> together by making a public "reset" function that I could call after
> calling show, but that is kludgier than I would like if I could avoid
> it. Thanks.
>
> -----------------------------------------------
> Israel Brewster
> Computer Support Technician
> Frontier Flying Service Inc.
> 5245 Airport Industrial Rd
> Fairbanks, AK 99709
> (907) 450-7250 x293
> -----------------------------------------------
>
>
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