[Qt-interest] dataChanged() SIGNAL in proxy models

[Stephen Kelly]

Mandeep Sandhu wrote:

>>> List = 1,2,3,4,5
>>>
>>> Table:
>>> 1,2,3
>>> 4,5
>>
>> You might have seen these, but I'll draw your attention to them anyway:
>>
>> http://doc.trolltech.com/latest/qlistview.html#LayoutMode-enum
>> http://doc.trolltech.com/latest/qlistview.html#batchSize-prop
>>
>> It doesn't really make the data tabular, but it will lay it out in rows.
> 
> I had tried it sometime back. Didn't seem to work then. This is what I
> had tried (some quick code):
> 
> class Widget : public QWidget
> {
> 
> public:
>     Widget(QWidget *parent = 0) : QWidget(parent)
>     {
>         QStringListModel *model = new QStringListModel(this);
>         QStringList list;
>         list << "0" << "1" << "2" << "3" << "4" << "5";
>         model->setStringList(list);
>         QListView *view  = new QListView(this);
>         view->setModel(model);
>         view->setLayoutMode(QListView::Batched);
>         view->setBatchSize(3);
>         QVBoxLayout *vb = new QVBoxLayout(this);
>         vb->addWidget(view);
>     }
>     ~Widget() {}
> };
> 
> int main(int argc, char *argv[])
> {
>     QApplication a(argc, argv);
>     Widget w;
>     w.show();
>     return a.exec();
> }
> 
> Another problem is that I cannot control the number rows that should
> be displayed. Setting batch size, I presume, will layout the list
> items with columns = batchSize and rows  = (total num of list
> items)/batchSize [+1 if it's not fully divisable by batchSize]

That's what I thought too, but on reading the docs again, it seems that's 
not right. That API is about delaying the layouting of items, not grouping 
of items.

I tried using other api like 

      view->setViewMode(QListView::IconMode);
      view->setWrapping(true);
      view->setGridSize(QSize(30, 20));

but I couldn't make that work either.

It seems like something that should be possible though, maybe someone else 
knows.

All the best,

Steve.

> 
>>
>>>
>>> The reason I'm doing this is because the source of the data is
>>> returning a list but the display has to be tabular (I could still
>>> extract the list data and populate a table model, but I though this
>>> might turn out to be easier).
>>
>> If the choice really is between a proxy to turn the stuff into a table or
>> implement your own model to structure the data in a tabular way in the
>> first place, I still recommend the table model, not the proxy.
> 
> Ok. Will think about it.
> 
> Thanks,
> -mandeep