imageloader.hpp Example File

    /* Copyright (c) 2012, 2013  BlackBerry Limited.
     *
     * Licensed under the Apache License, Version 2.0 (the "License");
     * you may not use this file except in compliance with the License.
     * You may obtain a copy of the License at
     *
     * http://www.apache.org/licenses/LICENSE-2.0
     *
     * Unless required by applicable law or agreed to in writing, software
     * distributed under the License is distributed on an "AS IS" BASIS,
     * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     * See the License for the specific language governing permissions and
     * limitations under the License.
     */

    #ifndef IMAGELOADER_HPP
    #define IMAGELOADER_HPP

    #include <QImage>
    #include <QByteArray>

    #include <bb/cascades/Image>

    /*
     * This class retrieves an image from the web, then converts the binary
     * data into a bb::cascades::Image and makes it available through a property.
     */
    class ImageLoader : public QObject
    {
        Q_OBJECT

        Q_PROPERTY(QVariant image READ image NOTIFY imageChanged)
        Q_PROPERTY(QString label READ label NOTIFY labelChanged)

        Q_PROPERTY(bool loading READ loading NOTIFY loadingChanged)

    public:
        /*
         * Creates a new image loader.
         *
         * @param imageUrl The url to load the image from.
         */
        ImageLoader(const QString &imageUrl, QObject* parent = 0);

        /*
         * Destroys the image loader.
         */
        ~ImageLoader();

        /*
         * Loads the image.
         */
        void load();

    Q_SIGNALS:
        // The change notification signals of the properties
        void imageChanged();
        void labelChanged();
        void loadingChanged();

    private Q_SLOTS:
        /*
         * Response handler for the network operation.
         */
        void onReplyFinished();

        /*
         * Response handler for the image process operation.
         */
        void onImageProcessingFinished();

    private:
        // The accessor methods of the properties
        QVariant image() const;
        QString label() const;
        bool loading() const;

        // The property values
        bb::cascades::Image m_image;
        QString m_label;
        bool m_loading;

        // The URL of the image that should be loaded
        QString m_imageUrl;

        // The thread status watcher
        QFutureWatcher<QImage> m_watcher;
    };

    #endif