ubuntu-phone team mailing list archive

["Vladimir M." <mlvl.jr@xxxxxxxxx>]

CONSTANT (or whatever the name is) helps here as well -- if the prop does
not change  :)


On Wed, Oct 2, 2013 at 7:58 PM, Николай Шатохин <n.shatokhin@xxxxxxxxx>wrote:

> Hm, yes, it helps. Thank you.
>
>
> 2013/10/2 Roman Shchekin <mrqtros@xxxxxxxxx>
>
>> You should register Game via qmlRegisterType too.
>>
>> Your Engine's "game" property used in binding and it has no NOTIFY
>> signal.
>> I hope you know what is it. If no - you should learn basics of Qt first.
>>
>> Cheers,
>> Roman.
>>
>>
>> 2013/10/2 Николай Шатохин <n.shatokhin@xxxxxxxxx>
>>
>>> I did it, but now I got:
>>>
>>> QMetaProperty::read: Unable to handle unregistered datatype 'Game*' for
>>> property 'Engine::game'
>>>
>>> QQmlExpression: Expression qrc:/Reactor.qml:7 depends on non-NOTIFYable
>>> properties:
>>>
>>> Engine::game
>>>
>>> On application startup (game is Q_PROPERY of Engine and has type Game *).
>>>
>>>
>>> 2013/10/2 Vladimir M. <mlvl.jr@xxxxxxxxx>
>>>
>>>> Just put the star in the property decl -- it's the stock way to do it,
>>>> and the decl w/o star will be deprecated probably soon, as far as I know.
>>>> Then, bind to the props in qml, and that's it!
>>>> 02 окт. 2013 г. 14:31 пользователь "Николай Шатохин" <
>>>> n.shatokhin@xxxxxxxxx> написал:
>>>>
>>>>
>>>>> Ok, I registered as Type class Ship inherited from QObject that have
>>>>> fields:
>>>>>
>>>>> Q_PROPERTY(Hull hull READ hull)
>>>>> Q_PROPERTY(Reactor reactor READ reactor)
>>>>> Q_PROPERTY(Shields shields READ shields)
>>>>>
>>>>> (all field classes inherited from QObject too)
>>>>>
>>>>> But in ship class I'm using this fields as pointers (Hull * hull). So,
>>>>> how to use correctly Q_Properties in this case? (I need call methods from
>>>>> this fields and catch signals from them in QML)
>>>>>
>>>>>
>>>>>
>>>>> 2013/9/30 Vladimir M. <mlvl.jr@xxxxxxxxx>
>>>>>
>>>>>> Sure, you can always wire as many objects as possible to smth
>>>>>> existing in a scene or set as a context property -- it's a simple
>>>>>> Q_PROPERTY assignment on the C++ side, with a pointer passed to the setter
>>>>>> (and works as soon as you declare the property on the QML side (or register
>>>>>> and instantiate a C++ implemented item)).
>>>>>>
>>>>>> After all, these are ordinary QObejcts passing pointers (to each
>>>>>> other) to each other :)
>>>>>> (plus some memory management -- automatic on the QML side, and
>>>>>> QObject parent-tree based on the C++ side)
>>>>>>
>>>>>> Vladimir
>>>>>>
>>>>>>
>>>>>> On Mon, Sep 30, 2013 at 6:24 PM, Николай Шатохин <
>>>>>> n.shatokhin@xxxxxxxxx> wrote:
>>>>>>
>>>>>>> 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
>>>>>>>>>>> Unsubscribe : https://launchpad.net/~ubuntu-phone
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>>>>>>>>>>>
>>>>>>>>>>>
>>>>>>>>>>
>>>>>>>>>
>>>>>>>>
>>>>>>>
>>>>>>
>>>>>
>>>
>>
>
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