[Qt-qml] [MAYBE SOLVED] Possibility of an implementation approach?

[Christian Benjamin Ries]

I added a "resize"-method and call this when I add elements. Is this a good approach or does QML 
support something like this native?

[QML]
    width: baseWidth; height: baseHeight;

   function resizeHost() {
     hostItem.height = repeaterServices.count * 20 + baseHeight;
   }

   Column {
       spacing: 1;
       Repeater {
         id: repeaterServices;
         model: modelServices;
         Service {
           objectName: "service" + index;
           serviceName: model.modelData.name;
           iconPath: model.modelData.iconPath;
           textColor: model.modelData.color;
         }
       }
     }
[/QML]

[CPP]
QMetaObject::invokeMethod(objectHost, "resizeHost");
[/CPP]

Am 10/09/11 14:22, schrieb 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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