[Qt-qml] Possibility of an implementation approach?

[Christian Benjamin Ries]

Brilliant, good information for my task, thanks!

Currently, I have an implementation in C++ to add items to the view and I can use mouse-clicks. Now, 
I have one problem, how can I resize my parent item/rectangle to a fitted size, depending on the 
elements in my list? A screenshot is here [1].

I tried to use methods of QList, like count() to get the count of elements and to resize the view 
then, unfortunately count() does not exist.

And in QML I use:
[QML]
   // Area for service elements.
   Item {
     anchors.top: hostTop.bottom;
     anchors.topMargin: 10;
     x: 30;
     Column {
       spacing: 1;
       Repeater {
         model: modelServices;
         Service {
           serviceName: model.modelData.name;
           iconPath: model.modelData.iconPath;
           textColor: model.modelData.color;
         }
       }
     }
     //parent.height: modelServices.count * 20;
   } // Item
[/QML]

Suggestions?

[1] http://christianbenjaminries.de/dl/_qml_/question01.png

Am 10/09/11 01:09, schrieb ray.rischpater at nokia.com:
> My first medium-sized-ish QML application was one very similar to what you're proposing, and the approach worked very well. Two comments...
> You'll want to use a C++ model to back your UI for your network resources; that way you can update the model from C++ and the UI will automatically redraw. You'll want to create a subclass of QAbstractListModel, or use a subclass like QStandardItemModel (which is fine for general lightweight work), and jam that puppy into your QML context (http://doc.qt.nokia.com/4.7-snapshot/qtbinding.html#embedding-c-objects-into-qml-components, http://www.lothlorien.com/kf6gpe/?p=160). Using a model is preferable to using QList<T>, because as the model changes, it signals to the UI to change automatically. In my case, I created a QStandardItemModel subclass that was a back-end listening to QtDBus notifications, so signals on the DBus propagated to, and seamlessly updated, my QML interface. It worked very well.
>
> You can wire stuff back to your C++ app from your QML's ListView delegate by using a MouseArea that dispatches to a Q_INVOKABLE property on an object shared between C++ and QML; see the previous links as  well. I found it pretty handy (if a bit sloppy) to make my application controller class available in QML, and then just put some Q_INVOKABLE methods on it so that the QML could trigger state changes in the app controller logic. So your app controller could have a Q_INVOKABLE method "doSomething" that the MouseArea onClicked handler invokes, passing whatever info from the current item of the model is necessary to your application logic.
>
> Hope that helps!
>
> Cheers,
> R.
>
>
> -----Original Message-----
> From: qt-qml-bounces+ray.rischpater=nokia.com at qt.nokia.com [mailto:qt-qml-bounces+ray.rischpater=nokia.com at qt.nokia.com] On Behalf Of ext Christian Benjamin Ries
> Sent: Wednesday, September 07, 2011 6:17 AM
> To: qt-qml at qt.nokia.com
> Subject: [Qt-qml] Possibility of an implementation approach?
>
> Hello all together!
>
> I rechecherd a little bit and checked out the possibilities of QML, everything sounds nice and easy to apply. I already checked how I can add an QML declarative object to a GraphicScene and how I could move them around.
>
> Now I stuck, I've no idea if I can use QML efficiently in my project.
>
> Here a small description of my task:
>
> - I have to create a graphical view of some elements, e.g. a host with included childs like network-interface cards.
>
> - These hosts could have descriptions for file-shares, and I like to add them to the host on the fly by a C++-programm, and the view sould be repaint in the QGraphicalView.
>
> - I have seen, that I can add a list<T>  in QML, could I add elements to this list by C++? If yes, could you give me an example or a link to one example?
>
> - Furthermore, when I click a one MouseArea I like to use this click-Signal in my C++-programm, but there is no available example on the Qt's-website, right?
>
> I really like to use QML, because it could safe a lot of time! Because their is no need to create items of all elements with a QGraphicsItem based spezialization, and the calculation of all positions and so on...
>
> I really checked the web and Qt's documentation, but the available examples covers not really an example how I could do the mentioned implementation things.
>
> Suggestions will be welcome(!)
>
> All the best, Christian
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-- 
Dipl.-Ing. (FH) Christian Benjamin Ries, M.Sc.
University of Applied Sciences Bielefeld
Department of Engineering Sciences and Mathematics
Computational Materials Science&  Engineering (CMSE)

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