ProgressDialog.hpp Example File

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    #ifndef PROGRESSDIALOG_HPP
    #define PROGRESSDIALOG_HPP

    #include <QtCore/QFutureWatcher>
    #include <QtCore/QObject>

    /**
     * This sample application shows how to use Future objects from QtConcurrent
     * to monitor and change the state of a running computation.
     * The application provides an UI where the user can start an computation that
     * is distributed over all available CPU cores by the QtConcurrent framework.
     * A progress bar shows the current progress of the computation and the user
     * can cancel the computation at any point in time.
     */
    class ProgressDialog : public QObject
    {
        Q_OBJECT

        // Makes the number of available CPU cores available to the UI
        Q_PROPERTY(int numberOfCores READ numberOfCores NOTIFY numberOfCoresChanged)

        // Makes the current state of the application available to the UI
        Q_PROPERTY(bool active READ active NOTIFY activeChanged);

        // Makes the minimum of the progress indicator available to the UI
        Q_PROPERTY(int progressMinimum READ progressMinimum NOTIFY progressRangeChanged)

        // Makes the maximum of the progress indicator available to the UI
        Q_PROPERTY(int progressMaximum READ progressMaximum NOTIFY progressRangeChanged)

        // Makes the current progress value available to the UI
        Q_PROPERTY(int progressValue READ progressValue NOTIFY progressValueChanged)

    public:
        ProgressDialog();

        // The accessor methods for the properties
        int numberOfCores() const;
        bool active() const;
        int progressMinimum() const;
        int progressMaximum() const;
        int progressValue() const;

    public Q_SLOTS:
        // This method is invoked when the user clicks on the 'Start' button in the UI
        void startComputation();

        // This method is invoked when the user clicks the 'Cancel' button in the UI
        void cancelComputation();

    Q_SIGNALS:
        // The change notification signals of the properties
        void numberOfCoresChanged();
        void activeChanged();
        void progressRangeChanged();
        void progressValueChanged();

    private Q_SLOTS:
        // This slot is invoked whenever the future reports a change of the progress range
        void progressRangeChanged(int minimum, int maximum);

        // This slot is invoked whenever the future reports a change of the current progress value
        void progressValueChanged(int value);

        // This slot is invoked whenever the future reports to be finished
        void calculationFinished();

    private:
        // The future watcher that provides monitoring for the currently running computation
        QFutureWatcher<void> m_futureWatcher;

        // The minimum progress value
        int m_progressMinimum;

        // The maximum progress value
        int m_progressMaximum;

        // The current progress value
        int m_progressValue;
    };

    #endif