[Qt-interest] Model/View Help

[Jeroen De Wachter]

Hey Colin,

The choice of using item-based or model-based widgets is really up to 
you, but I find that the model-based approach tends to result in cleaner 
code in your GUI classes, as the model reacts to changes. The item-based 
approach usually means lots of methods in the GUI classes to handle 
changes to the items (both from the data to the GUI and as a result of 
user interaction).

However, if you simply need to populate a table and have it display some 
information, without the need to modify it, then writing a model seems 
like overkill and you may be better off just filling in the information 
from the GUI class using QTableWidget::setItem.

Subclassing the QWidgets (QTableWidget / QTableView) themselves should 
not be necessary in any case, you just need to interact with them.

If you use a model-based approach, you will need to subclass a 
QAbstractItemModel that contains your QList and is able to return the 
data. You can also subclass a QAbstractTableModel instead, if your data 
only needs to be displayed in a table. QAbstractTableModel provides 
default implementations for most of the methods defined in 
QAbstractItemModel that you don't generally want to deal with when 
you're displaying things in a table (like parent/child relationships, 
which you likely don't have).
Just use the row as an index for your QList and use the columns to 
access the different members of your custom class.

I wrote a table model just last week and it only contains the rowCount, 
columnCount and data methods. Just read the documentation on 
QAbstractTableModel. You could also take a look at the addressbook 
example in the itemviews folder.

Kind regards,

Jeroen

Colin Kern wrote:
> Hello all,
>
> I'm new to models/view programming and I have a question.  Let's say I
> have a C++ class that defines some member variables, and I have a
> container storing a bunch of instances of this class (let's say it's a
> QList).  What I want to do is display a table where each row is an
> instance of this class, and each column is showing the value of one of
> the member variables.  What's the best way to do this?  Should I use
> QTableWidget or QTableView? Do I need to subclass one of the Qt model
> classes, or can I use an existing one?  I've been trying to figure out
> how to do this, but every solution I come up with seems more
> complicated than it should be.
>
> Thanks,
> Colin Kern
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> Qt-interest at trolltech.com
> http://lists.trolltech.com/mailman/listinfo/qt-interest
>
>   



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