ubuntu-phone team mailing list archive

["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
>>> Unsubscribe : https://launchpad.net/~ubuntu-phone
>>> More help   : https://help.launchpad.net/ListHelp
>>>
>>>
>>
>