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[Николай Шатохин <n.shatokhin@xxxxxxxxx>]

What if I will create property backend in QML type and then I will set this
property in all QML objects to global object? So, theoretically this can
solve my problem.


2013/9/30 Vladimir M. <mlvl.jr@xxxxxxxxx>

> Then, it looks like the standard way would be to have an instance of the
> item embedded in each page in the stack.
>
> If this turns out to be too resource consuming, you may try to play some
> tricks like removing it from all the pages and overlaying over the whole
> stack (if the item will always be in the same place, and have the same
> geometry, this will be rather simple, children order or z-value will allow
> it place it on top).
>
> If geometry is different for each page, this may get trickier (ultimate
> solution may be some sort of a "placeholder item" having the right place in
> each page, to which the item gets parented when the placeholder becomes
> visible, with "fill" anchoring).
>
> On the other hand, if the item has to have it's state consistent between
> the pages, then even if its is feasible performance-wise to embed it into
> all of them, some sort of common "view state model" should probably exist,
> and this again suggests just using a single instance...
>
> Vladimir
>
>
> On Mon, Sep 30, 2013 at 3:07 PM, Николай Шатохин <n.shatokhin@xxxxxxxxx>wrote:
>
>> I need to have this object in different qml files (for i.e. GameChat must
>> be shown on GameCreation,Game,GameResults pages: this it differents QML
>> files and differents pages in PageStack), but I created only one
>> QtQuickView in main.cpp. So, do view is qml file or QtQuckView object?
>>
>>
>> 2013/9/30 Vladimir M. <mlvl.jr@xxxxxxxxx>
>>
>> You probably can't share a single instance of a QML visual item between
>>> views, but as soon as you have the type registered properly / importable /
>>> etc, you can use instantiate it in as many views as you like.
>>> A QObject pointer can be passed around to items living in different
>>> veiws inside the same application, of course (but watch out for memory
>>> management issues -- see CppOwnership / QMLOwnership  / etc in the docs
>>> under "memory management").
>>>
>>> Easiest way may be to set the same object as a context prop for several
>>> views (unless you have some objections to this practice, like ones
>>> mentioned up in the thread).
>>>
>>> Lastly, there is that (legitimate) trick allowing QML items to be
>>> "rendered" by other items, resulting in the same item being shown in
>>> multiple places of the same scene (but being manipalatable anywhere except
>>> its actual position) -- look into the shader effects and such.
>>>
>>>
>>> On Mon, Sep 30, 2013 at 2:34 PM, Николай Шатохин <n.shatokhin@xxxxxxxxx>wrote:
>>>
>>>> What if I need to show the same QML object in two different places? How
>>>> to do this? How to create new QML object without recreating it in C++?
>>>>
>>>>
>>>> 2013/9/30 Николай Шатохин <n.shatokhin@xxxxxxxxx>
>>>>
>>>>> 0_o. I didn't know that all objects in QML are global. Thank you very
>>>>> much.
>>>>>
>>>>>
>>>>> 2013/9/30 <mrqtros@xxxxxxxxx>
>>>>>
>>>>>  Omg declare global engine object in main qml file and that's all
>>>>>>
>>>>>> 30.09.13 13:19 Николай Шатохин написал(а):
>>>>>> I'm using qmlRegisterType now. I have problems, because two QML
>>>>>> objects in different QML files it is two different objects in C++. I
>>>>>> registered as type class that have static object of Engine, but now I have
>>>>>> butthurt with it (I need retranslate all signals, getters and setters)
>>>>>>
>>>>>>
>>>>>> 2013/9/30 Michael Zanetti <michael.zanetti@xxxxxxxxxxxxx>
>>>>>>
>>>>>>> On Monday 30 September 2013 12:05:03 Николай Шатохин wrote:
>>>>>>> > Can I set only one object as context property that contains other
>>>>>>> objects
>>>>>>> > (and this objects contain objects too) and get this deep objects
>>>>>>> in QML?
>>>>>>> >
>>>>>>> > For i.e. I have object of class Engine that has object of class
>>>>>>> Game, Game
>>>>>>> > contains object of Ship and Ship contains object of Reactor. So, I
>>>>>>> set
>>>>>>> > object of Engine as context property and in QML write:
>>>>>>> >
>>>>>>> > engine.game.ship.reactor
>>>>>>> >
>>>>>>> > Can I use it?
>>>>>>>
>>>>>>>
>>>>>>> Yes, given that "game" is a Q_PROPERTY() of "enigne", "ship" is a
>>>>>>> Q_PROPERTY()
>>>>>>> of "game" etc...
>>>>>>>
>>>>>>> Still, I recommend to register the type of the Engine instead of
>>>>>>> setting it as
>>>>>>> a context property.
>>>>>>>
>>>>>>> It's really just using qmlRegisterType() instead of
>>>>>>> setContextProperty(). It's
>>>>>>> not more or more complex code, but gives you better ways of
>>>>>>> structuring your
>>>>>>> QML code.
>>>>>>>
>>>>>>> >
>>>>>>> >
>>>>>>> > 2013/9/30 Николай Шатохин <n.shatokhin@xxxxxxxxx>
>>>>>>> >
>>>>>>> > > I've already found this solution:
>>>>>>> > >
>>>>>>> http://qt-project.org/doc/qt-5.0/qtqml/qtqml-cppintegration-contextpropert
>>>>>>> > > ies.html It helps. Thanks.
>>>>>>> > >
>>>>>>> > >
>>>>>>> > > 2013/9/30 Michael Zanetti <michael.zanetti@xxxxxxxxxxxxx>
>>>>>>> > >
>>>>>>> > >> On Sunday 29 September 2013 13:45:01 Vladimir M. wrote:
>>>>>>> > >> > Sounds like a "context property" use case (you plain set a
>>>>>>> QObject as a
>>>>>>> > >> > context property for a view's root scope, w/o even
>>>>>>> registering the
>>>>>>> > >>
>>>>>>> > >> object's
>>>>>>> > >>
>>>>>>> > >> > type, and all its properties and invokables become available).
>>>>>>> > >>
>>>>>>> > >> I don't recommend using context properties. While they are
>>>>>>> useful for
>>>>>>> > >> some
>>>>>>> > >> cases, this one doesn't seem to be one of those. Using too many
>>>>>>> global
>>>>>>> > >> context
>>>>>>> > >> properties can make the code very ugly to work with.
>>>>>>> > >>
>>>>>>> > >> You probably want to create something like this:
>>>>>>> > >>
>>>>>>> > >> class ViewController: public QObject
>>>>>>> > >> {
>>>>>>> > >>
>>>>>>> > >>   Q_PROPERTY(QList<MyClass> viewObjects READ viewObjects NOTIFY
>>>>>>> > >>
>>>>>>> > >> viewObjectsChanged)
>>>>>>> > >> ...
>>>>>>> > >> QList<MyClass> viewObjects() const {
>>>>>>> > >>
>>>>>>> > >>   return objectList;
>>>>>>> > >>
>>>>>>> > >> }
>>>>>>> > >> ...
>>>>>>> > >> };
>>>>>>> > >>
>>>>>>> > >> qmlRegisterType<ViewController>(uri, 0, 1, "ViewController");
>>>>>>> > >>
>>>>>>> > >> Then in QML you can do something like this:
>>>>>>> > >>
>>>>>>> > >> ViewController {
>>>>>>> > >>
>>>>>>> > >>   id: viewController
>>>>>>> > >>
>>>>>>> > >> }
>>>>>>> > >>
>>>>>>> > >> Repeater {
>>>>>>> > >>
>>>>>>> > >>   model: viewController.viewObjects
>>>>>>> > >>   MyView {
>>>>>>> > >>
>>>>>>> > >>     property var viewObject: viewController.viewObjects[index]
>>>>>>> > >>
>>>>>>> > >>   }
>>>>>>> > >>
>>>>>>> > >> }
>>>>>>> > >>
>>>>>>> > >>
>>>>>>> > >> Note that if you want your code to adjust more flexible (i.e.
>>>>>>> the
>>>>>>> > >> viewObjects
>>>>>>> > >> change a lot), consider using a QAbstractListModel (or some
>>>>>>> other model)
>>>>>>> > >> instead of a QList.
>>>>>>> > >>
>>>>>>> > >> Hope this helps,
>>>>>>> > >> Michael
>>>>>>> > >>
>>>>>>> > >> > On Sun, Sep 29, 2013 at 6:38 AM, Николай Шатохин
>>>>>>> > >>
>>>>>>> > >> <n.shatokhin@xxxxxxxxx>wrote:
>>>>>>> > >> > > Hello.
>>>>>>> > >> > >
>>>>>>> > >> > > When I create a class in C++, I can register it for QML and
>>>>>>> can
>>>>>>> > >> > > create
>>>>>>> > >> > > view for it. It's very convenient. But, if I need many
>>>>>>> objects of the
>>>>>>> > >>
>>>>>>> > >> same
>>>>>>> > >>
>>>>>>> > >> > > type, and need to show few views on screen, I got problems.
>>>>>>> > >> > > Is it possible to register QML type for object, not for
>>>>>>> class?
>>>>>>> > >> > > If I change some object, I need to see only its view
>>>>>>> changed.
>>>>>>> > >> > >
>>>>>>> > >> > > Best regard,
>>>>>>> > >> > > Nick
>>>>>>> > >> > >
>>>>>>> > >> > > --
>>>>>>> > >> > > Mailing list: https://launchpad.net/~ubuntu-phone
>>>>>>> > >> > > Post to     : ubuntu-phone@xxxxxxxxxxxxxxxxxxx
>>>>>>> > >> > > Unsubscribe : https://launchpad.net/~ubuntu-phone
>>>>>>> > >> > > More help   : https://help.launchpad.net/ListHelp
>>>>>>>
>>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>>
>>>> --
>>>> Mailing list: https://launchpad.net/~ubuntu-phone
>>>> Post to     : ubuntu-phone@xxxxxxxxxxxxxxxxxxx
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>>>>
>>>>
>>>
>>
>