QDeclarativeImageProvider is not an QObject, so the model and image
provider might be implemented in the same class:
class MyAwesomeModel: public QAbstractItemModel, public
QDeclarativeImageProvider
{
//...
};
The upside of this solution is that you can have a single data
structure, so you don't have to implement data synchronization between
model and image provider.
2010/11/19 <ray.rischpa...@nokia.com>:
> Actually, you can return different images using the QDeclarativeImageProvider
> and a C++ model --- simply have a role in the model return a different string
> resource name for each model item (e.g., "image://model/1.png",
> "image://model/2.png", and so forth), and then have the image provider return
> the appropriate image from the model. If you want to be a bit faster, you can
> even have your image provider use a QMap<QString, QModelIndex> to map from
> the image's name in the model to the image. Based on Juha's feedback, I've
> got code running now I'm planning on cleaning up a bit and posting to my blog
> in the near future. The crux of the code is the requestPixmap method, which
> looks like this:
>
> class QAbstractItemModel;
>
> class ModelIndexProvider : public QObject, public QDeclarativeImageProvider
> {
> Q_OBJECT
> public:
> ModelIndexProvider(QAbstractItemModel& model, int pathRole, int
> pixmapRole, QObject* parent = 0);
> ~ModelIndexProvider();
> QPixmap requestPixmap(const QString& id, QSize* size, const QSize&
> requestedSize);
>
> public slots:
> void dataUpdated(const QModelIndex & topLeft, const QModelIndex &
> bottomRight);
> void dataDeleted(const QModelIndex & parent, int start, int end);
> void dataReset();
>
> private:
> QAbstractItemModel& mModel;
> int mPathRole;
> int mPixmapRole;
> QMap<QString, QModelIndex> mPixmapIndex;
> };
>
> QPixmap ModelIndexProvider::requestPixmap(const QString& id, QSize* size,
> const QSize& requestedSize)
> {
> QString key = QString("image://model/%1").arg(id);
> QModelIndex index = mPixmapIndex[key];
> QPixmap image = mModel.data(index, mPixmapRole).value<QPixmap>();
> QPixmap result;
>
> if (requestedSize.isValid()) {
> result = image.scaled(requestedSize, Qt::KeepAspectRatio);
> } else {
> result = image;
> }
> *size = result.size();
> return result;
> }
>
> Of course, the provider should be a QObject and connect to the model so that
> when the model changes the pixmap index gets updated and so forth, but that's
> pretty easy.
>
> Thanks again to Juha for the suggestion!
>
> On Nov 18, 2010, at 10:56 PM, ext Tuomas Niinistö wrote:
>
>> Juha Turunen <turu...@...> writes:
>>
>>>
>>> Hi Ray,
>>>
>>> [ Use QDeclarativeImageProvider ]
>>>
>>> On Fri, Nov 12, 2010 at 7:42 PM, <ray.rischpa...@...> wrote:
>>>> [ Question about returning images from models ]
>>>> Nokia Research Center Palo Alto
>>
>> Hi,
>>
>> I have faced the same problem as Ray. And think that the
>> QDeclarativeImageProvider does not help here, at least not directly.
>>
>> When you have a list object existing in native C++ side and you wan't to
>> populate the QML ListView with it. For "normal" data like integers and
>> strings
>> it works fine by using QDeclarativeListProperty.
>>
>> But the problem comes when you want to have an individual image for each list
>> item. With QDeclarativeImageProvider you can populate the list items with the
>> same image instance, but how to have an individual image for each item seems
>> to
>> be problematic.
>>
>> Br, Tuomas
>>
>>
>>
>>
>> _______________________________________________
>> Qt-qml mailing list
>> Qt-qml@trolltech.com
>> http://lists.trolltech.com/mailman/listinfo/qt-qml
>
>
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