#include <QtGui>
class LightWidget : public QWidget
{
Q_OBJECT
Q_PROPERTY(bool on READ isOn WRITE setOn)
public:
LightWidget(const QColor &color, QWidget *parent = 0)
: QWidget(parent), m_color(color), m_on(false) {}
bool isOn() const
{ return m_on; }
void setOn(bool on)
{
if (on == m_on)
return;
m_on = on;
update();
}
public slots:
void turnOff() { setOn(false); }
void turnOn() { setOn(true); }
protected:
virtual void paintEvent(QPaintEvent *)
{
if (!m_on)
return;
QPainter painter(this);
painter.setRenderHint(QPainter::Antialiasing);
painter.setBrush(m_color);
painter.drawEllipse(0, 0, width(), height());
}
private:
QColor m_color;
bool m_on;
};
class TrafficLightWidget : public QWidget
{
public:
TrafficLightWidget(QWidget *parent = 0)
: QWidget(parent)
{
QVBoxLayout *vbox = new QVBoxLayout(this);
m_red = new LightWidget(Qt::red);
vbox->addWidget(m_red);
m_yellow = new LightWidget(Qt::yellow);
vbox->addWidget(m_yellow);
m_green = new LightWidget(Qt::green);
vbox->addWidget(m_green);
QPalette pal = palette();
pal.setColor(QPalette::Background, Qt::black);
setPalette(pal);
setAutoFillBackground(true);
}
LightWidget *redLight() const
{ return m_red; }
LightWidget *yellowLight() const
{ return m_yellow; }
LightWidget *greenLight() const
{ return m_green; }
private:
LightWidget *m_red;
LightWidget *m_yellow;
LightWidget *m_green;
};
QState *createLightState(LightWidget *light, int duration, QState *parent = 0)
{
QState *lightState = new QState(parent);
QTimer *timer = new QTimer(lightState);
timer->setInterval(duration);
timer->setSingleShot(true);
QState *timing = new QState(lightState);
QObject::connect(timing, SIGNAL(entered()), light, SLOT(turnOn()));
QObject::connect(timing, SIGNAL(entered()), timer, SLOT(start()));
QObject::connect(timing, SIGNAL(exited()), light, SLOT(turnOff()));
QFinalState *done = new QFinalState(lightState);
timing->addTransition(timer, SIGNAL(timeout()), done);
lightState->setInitialState(timing);
return lightState;
}
class TrafficLight : public QWidget
{
public:
TrafficLight(QWidget *parent = 0)
: QWidget(parent)
{
QVBoxLayout *vbox = new QVBoxLayout(this);
TrafficLightWidget *widget = new TrafficLightWidget();
vbox->addWidget(widget);
vbox->setMargin(0);
QStateMachine *machine = new QStateMachine(this);
QState *redGoingYellow = createLightState(widget->redLight(), 3000);
redGoingYellow->setObjectName("redGoingYellow");
QState *yellowGoingGreen = createLightState(widget->yellowLight(), 1000);
yellowGoingGreen->setObjectName("yellowGoingGreen");
redGoingYellow->addTransition(redGoingYellow, SIGNAL(finished()), yellowGoingGreen);
QState *greenGoingYellow = createLightState(widget->greenLight(), 3000);
greenGoingYellow->setObjectName("greenGoingYellow");
yellowGoingGreen->addTransition(yellowGoingGreen, SIGNAL(finished()), greenGoingYellow);
QState *yellowGoingRed = createLightState(widget->yellowLight(), 1000);
yellowGoingRed->setObjectName("yellowGoingRed");
greenGoingYellow->addTransition(greenGoingYellow, SIGNAL(finished()), yellowGoingRed);
yellowGoingRed->addTransition(yellowGoingRed, SIGNAL(finished()), redGoingYellow);
machine->addState(redGoingYellow);
machine->addState(yellowGoingGreen);
machine->addState(greenGoingYellow);
machine->addState(yellowGoingRed);
machine->setInitialState(redGoingYellow);
machine->start();
}
};
int main(int argc, char **argv)
{
QApplication app(argc, argv);
TrafficLight widget;
widget.resize(110, 300);
widget.show();
return app.exec();
}
#include "main.moc"