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     2 **

     3 ** Copyright (C) 2009 Nokia Corporation and/or its subsidiary(-ies).

     4 ** All rights reserved.

     5 ** Contact: Nokia Corporation (qt-info@nokia.com)

     6 **

     7 ** This file is part of the QtCore module of the Qt Toolkit.

     8 **

     9 ** $QT_BEGIN_LICENSE:LGPL$

    10 ** No Commercial Usage

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    12 ** You may use this file in accordance with the terms and conditions

    13 ** contained in the Technology Preview License Agreement accompanying

    14 ** this package.

    15 **

    16 ** GNU Lesser General Public License Usage

    17 ** Alternatively, this file may be used under the terms of the GNU Lesser

    18 ** General Public License version 2.1 as published by the Free Software

    19 ** Foundation and appearing in the file LICENSE.LGPL included in the

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    21 ** ensure the GNU Lesser General Public License version 2.1 requirements

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    23 **

    24 ** In addition, as a special exception, Nokia gives you certain additional

    25 ** rights.  These rights are described in the Nokia Qt LGPL Exception

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    36 **

    37 **

    38 ** $QT_END_LICENSE$

    39 **

    40 ****************************************************************************/

    41 

    42 #include <QtGui>

    43 

    44 //! [0]

    45 class LightWidget : public QWidget

    46 {

    47     Q_OBJECT

    48     Q_PROPERTY(bool on READ isOn WRITE setOn)

    49 public:

    50     LightWidget(const QColor &color, QWidget *parent = 0)

    51         : QWidget(parent), m_color(color), m_on(false) {}

    52 

    53     bool isOn() const

    54         { return m_on; }

    55     void setOn(bool on)

    56     {

    57         if (on == m_on)

    58             return;

    59         m_on = on;

    60         update();

    61     }

    62 

    63 public slots:

    64     void turnOff() { setOn(false); }

    65     void turnOn() { setOn(true); }

    66 

    67 protected:

    68     virtual void paintEvent(QPaintEvent *)

    69     {

    70         if (!m_on)

    71             return;

    72         QPainter painter(this);

    73         painter.setRenderHint(QPainter::Antialiasing);

    74         painter.setBrush(m_color);

    75         painter.drawEllipse(0, 0, width(), height());

    76     }

    77 

    78 private:

    79     QColor m_color;

    80     bool m_on;

    81 };

    82 //! [0]

    83 

    84 //! [1]

    85 class TrafficLightWidget : public QWidget

    86 {

    87 public:

    88     TrafficLightWidget(QWidget *parent = 0)

    89         : QWidget(parent)

    90     {

    91         QVBoxLayout *vbox = new QVBoxLayout(this);

    92         m_red = new LightWidget(Qt::red);

    93         vbox->addWidget(m_red);

    94         m_yellow = new LightWidget(Qt::yellow);

    95         vbox->addWidget(m_yellow);

    96         m_green = new LightWidget(Qt::green);

    97         vbox->addWidget(m_green);

    98         QPalette pal = palette();

    99         pal.setColor(QPalette::Background, Qt::black);

   100         setPalette(pal);

   101         setAutoFillBackground(true);

   102     }

   103 

   104     LightWidget *redLight() const

   105         { return m_red; }

   106     LightWidget *yellowLight() const

   107         { return m_yellow; }

   108     LightWidget *greenLight() const

   109         { return m_green; }

   110 

   111 private:

   112     LightWidget *m_red;

   113     LightWidget *m_yellow;

   114     LightWidget *m_green;

   115 };

   116 //! [1]

   117 

   118 //! [2]

   119 QState *createLightState(LightWidget *light, int duration, QState *parent = 0)

   120 {

   121     QState *lightState = new QState(parent);

   122     QTimer *timer = new QTimer(lightState);

   123     timer->setInterval(duration);

   124     timer->setSingleShot(true);

   125     QState *timing = new QState(lightState);

   126     QObject::connect(timing, SIGNAL(entered()), light, SLOT(turnOn()));

   127     QObject::connect(timing, SIGNAL(entered()), timer, SLOT(start()));

   128     QObject::connect(timing, SIGNAL(exited()), light, SLOT(turnOff()));

   129     QFinalState *done = new QFinalState(lightState);

   130     timing->addTransition(timer, SIGNAL(timeout()), done);

   131     lightState->setInitialState(timing);

   132     return lightState;

   133 }

   134 //! [2]

   135 

   136 //! [3]

   137 class TrafficLight : public QWidget

   138 {

   139 public:

   140     TrafficLight(QWidget *parent = 0)

   141         : QWidget(parent)

   142     {

   143         QVBoxLayout *vbox = new QVBoxLayout(this);

   144         TrafficLightWidget *widget = new TrafficLightWidget();

   145         vbox->addWidget(widget);

   146         vbox->setMargin(0);

   147 

   148         QStateMachine *machine = new QStateMachine(this);

   149         QState *redGoingYellow = createLightState(widget->redLight(), 3000);

   150         redGoingYellow->setObjectName("redGoingYellow");

   151         QState *yellowGoingGreen = createLightState(widget->yellowLight(), 1000);

   152         yellowGoingGreen->setObjectName("yellowGoingGreen");

   153         redGoingYellow->addTransition(redGoingYellow, SIGNAL(finished()), yellowGoingGreen);

   154         QState *greenGoingYellow = createLightState(widget->greenLight(), 3000);

   155         greenGoingYellow->setObjectName("greenGoingYellow");

   156         yellowGoingGreen->addTransition(yellowGoingGreen, SIGNAL(finished()), greenGoingYellow);

   157         QState *yellowGoingRed = createLightState(widget->yellowLight(), 1000);

   158         yellowGoingRed->setObjectName("yellowGoingRed");

   159         greenGoingYellow->addTransition(greenGoingYellow, SIGNAL(finished()), yellowGoingRed);

   160         yellowGoingRed->addTransition(yellowGoingRed, SIGNAL(finished()), redGoingYellow);

   161 

   162         machine->addState(redGoingYellow);

   163         machine->addState(yellowGoingGreen);

   164         machine->addState(greenGoingYellow);

   165         machine->addState(yellowGoingRed);

   166         machine->setInitialState(redGoingYellow);

   167         machine->start();

   168     }

   169 };

   170 //! [3]

   171 

   172 //! [4]

   173 int main(int argc, char **argv)

   174 {

   175     QApplication app(argc, argv);

   176 

   177     TrafficLight widget;

   178     widget.resize(110, 300);

   179     widget.show();

   180 

   181     return app.exec();

   182 }

   183 //! [4]

   184 

   185 #include "main.moc"