[Interest] QML introspection and dynamic component creation

[Harri Pasanen]

Ok, I wasn't reading carefully enough.

I don't have that much javascript mileage under the belt, but coming 
from python
I do see the value of introspection in some cases.

Might still be worthwhile to think about the design, usually explicit is 
better than implicit.

Harri

On 12/18/2011 09:44 PM, Bo Thorsen wrote:
> Sorry, Harri, but that's not the problem here.
>
> The problem was to look at the list of ParameterPanel children and
> create the objects based on the introspection. The problem is how to
> figure out which objects to create, not how to create them. Dynamic
> creation itself is easy enough.
>
> There are some things that can be done with the children[i], but I don't
> think it's enough. Not unless you do evil hacks like encode stuff in the
> objectName. Maybe some other parameter stuff could be used as a sort of
> homegrown introspection.
>
> Bo.
>
> Den 17-12-2011 11:04, Harri Pasanen skrev:
>> On 12/17/2011 10:15 AM, Bo Thorsen wrote:
>>>> When the user selects Wobble from the list of effects, a Loader is used
>>>> to create a WobbleEffect item, and the id of this item is assigned to
>>>> the effect property of the ParameterPanel. What I then want to happen is
>>>> for sliders to be created and connected [...]
>>> As you say, this is pretty easy to do with C++ introspection. So why not
>>> use that? Export a C++ function to QML that does this.
>>>
>>> I don't know of a way to do this in QML, but I'd be happy to know. So
>>> anyone with this knowledge, please step up and describe it.
>> You can probably do it trough javascript as well.
>>
>> For instance, I have a Piece.qml that acts  as kind of "class header" to
>> create instances of Piece qml objects.
>>
>>    From javascript I the do:
>>
>>     var component = Qt.createComponent("Piece.qml");
>>
>> pieces.push(component.createObject(gameBoard, {"x": xpos, "y": ypos,
>> "width": pw, "height": pw}
>>
>> to setup a gaming board.
>>
>> To connect the signals, at the end of Piece.qml I have something like:
>>
>>        Component.onCompleted: {
>>          mouse.swipe.connect(Ui.movePlayer)
>>
>> Where mouse.swipe is a signal I created for MouseArea {id: mouse ...} and
>> where Ui is my javascript, movePlayer being a function in there.
>>
>> Then to clear the board and remove the objects from screen I do:
>>
>>        for (var i in pieces)
>>            pieces[i].destroy()
>>
>>
>> So to lookup in docs is Qt.createComponent, createObject, connect, destroy.
>>
>> quickhit example is QtSDK is a full example to play around with.
>>
>> Hope this helps a bit,
>>
>> Harri
>>
>>
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>>
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>
> Bo Thorsen,
> Fionia Software.
>