Can I use QList of pointers? And get objects in QML.
2013/10/7 Николай Шатохин <n.shatok...@gmail.com> > Can I use QList (or something similar) as Q_PROPERTY? How can I use it in > QML? > > Best regards, > Nick > > > 2013/10/2 Vladimir M. <mlvl...@gmail.com> > > 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.shatok...@gmail.com> >> wrote: >> >>> Hm, yes, it helps. Thank you. >>> >>> >>> 2013/10/2 Roman Shchekin <mrqt...@gmail.com> >>> >>>> 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.shatok...@gmail.com> >>>> >>>>> 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...@gmail.com> >>>>> >>>>>> 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.shatok...@gmail.com> 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...@gmail.com> >>>>>>> >>>>>>>> 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.shatok...@gmail.com> 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...@gmail.com> >>>>>>>>> >>>>>>>>> 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.shatok...@gmail.com> 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...@gmail.com> >>>>>>>>>>> >>>>>>>>>>> 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.shatok...@gmail.com> 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.shatok...@gmail.com> >>>>>>>>>>>>> >>>>>>>>>>>>>> 0_o. I didn't know that all objects in QML are global. Thank >>>>>>>>>>>>>> you very much. >>>>>>>>>>>>>> >>>>>>>>>>>>>> >>>>>>>>>>>>>> 2013/9/30 <mrqt...@gmail.com> >>>>>>>>>>>>>> >>>>>>>>>>>>>> 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.zane...@canonical.com> >>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> 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.shatok...@gmail.com> >>>>>>>>>>>>>>>> > >>>>>>>>>>>>>>>> > > 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.zane...@canonical.com> >>>>>>>>>>>>>>>> > > >>>>>>>>>>>>>>>> > >> 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.shatok...@gmail.com>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@lists.launchpad.net >>>>>>>>>>>>>>>> > >> > > Unsubscribe : https://launchpad.net/~ubuntu-phone >>>>>>>>>>>>>>>> > >> > > More help : https://help.launchpad.net/ListHelp >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>>> >>>>>>>>>>>>>>> >>>>>>>>>>>>>>> >>>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>>> -- >>>>>>>>>>>>> Mailing list: https://launchpad.net/~ubuntu-phone >>>>>>>>>>>>> Post to : ubuntu-phone@lists.launchpad.net >>>>>>>>>>>>> Unsubscribe : https://launchpad.net/~ubuntu-phone >>>>>>>>>>>>> More help : https://help.launchpad.net/ListHelp >>>>>>>>>>>>> >>>>>>>>>>>>> >>>>>>>>>>>> >>>>>>>>>>> >>>>>>>>>> >>>>>>>>> >>>>>>>> >>>>>>> >>>>> >>>> >>> >>> -- >>> Mailing list: https://launchpad.net/~ubuntu-phone >>> Post to : ubuntu-phone@lists.launchpad.net >>> Unsubscribe : https://launchpad.net/~ubuntu-phone >>> More help : https://help.launchpad.net/ListHelp >>> >>> >> >
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