Repeater.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 REPEATER_HPP
    #define REPEATER_HPP

    #include <bb/cascades/Container>
    #include <bb/cascades/CustomControl>
    #include <QtCore/QList>

    /**
     * The Repeater has a "delegate" property of type QDeclarativeComponent*, which specifies the component
     * used for creating the QML elements. The "model" property specifies how often the element should be
     * repeated. Apart from using an integer constant here, it is also possible to specify a QVariantList
     * or a DataModel. For the later case, the variant and the map content of the VariantList and the
     * DataModel are made available in the created QML elements by setting them as their context property.
     *
     * The fact that writing "delegate: Label { ... }" in QML creates a QDeclarativeComponent* and not a
     * Label* is a special behavior of the QML engine. Internally, the QML engine checks if the property
     * (in this case "delegate") is of type QDeclarativeComponent*, and if so, treats the assignment as a
     * component assignment, not a item assignment.
     * The Repeater itself just sees a QDeclarativeComponent*, as that is what it gets passed from the QML
     * engine.
     */
    class Repeater : public bb::cascades::CustomControl
    {
        Q_OBJECT

        /**
         * The property that represents the model.
         * We use QVariant as type here so that the user can pass different type of models here.
         */
        Q_PROPERTY(QVariant model READ model WRITE setModel NOTIFY modelChanged)

        // The declarative component that is used as 'template' for the repeated elements
        Q_PROPERTY(QDeclarativeComponent *delegate READ delegate WRITE setDelegate NOTIFY delegateChanged)

        // Mark the 'delegate' property as default property
        Q_CLASSINFO("DefaultProperty", "delegate")

        public:
            Repeater(bb::cascades::Container *parent = 0);
            ~Repeater();

            // The accessor methods for the properties
            QVariant model() const;
            void setModel(const QVariant &model);

            QDeclarativeComponent *delegate() const;
            void setDelegate(QDeclarativeComponent *delegate);

        Q_SIGNALS:
            // The change notification signals of the properties
            void modelChanged();
            void delegateChanged();

        private:
            // This method clears the previsouly generated controls
            void clear();

            // This method regenerates new controls according to the current model data
            void regenerate();

            // The model data
            QVariant m_model;

            // The declarative component that is used as 'template' for the repeated elements
            QDeclarativeComponent *m_delegate;

            // The list of generated controls
            QList<bb::cascades::Control*> m_controls;
    };

    #endif