Untouchable Views

So there I was, having a look at implementing QListView and realising that, as a control/widget, it didn't have any direct item interaction methods whatsoever!

Oh, bugger...

Fortunately, as noted in my last post, I've been creating a BlitzMax version of a type of a item model which subclasses QAbstractItemModel. And for QComboBox it is working really well. Changes to items on the combo eek down into the BlitzMax item objects. Whenever you change data in these item objects, they emit events that the rest of the model/view framework can handle appropriately. It's all rather cool and groovy!

Anyway, back to QListView. It doesn't do very much, on the face of it, apart from display a list. Any (and all) interaction with the items is done via the model and the "selection model". Changes to the model filter up to the view automagically, and stuff appears (or disappears) in the visual list before your very eyes.
As a framework, it appears to work very well indeed. Of course, if you are used to doing stuff directly with controls/widgets it is a bit of a leap to start playing with the model instead, and simply ignoring the view altogether!

As an example, if we want to change the text for an item in QComboBox, we simply call :

setItemText(index:Int, text:String)

and all the real work of processing that information and is handled by QComboBox.
On the otherhand, if we want to change the text for an item in QListView, we need to :

model.setData(index:QModelIndex, text:String)

where index is a reference to the location of the item in the model (row, column, parent item).
Notice that we need the model, and a way to map our row/index to the model's index reference.

Once we set/update the data, the view will update the text accordingly.

So, when we are working with Views, look, but don't touch!

:o)