ubuntu-phone team mailing list archive

["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
>>>>>>> More help   : https://help.launchpad.net/ListHelp
>>>>>>>
>>>>>>>
>>>>>>
>>>>>
>>>>
>>>
>>
>