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// Copyright (C) 2016 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
#include <QtCore/QTimer>
#include <QtGui/QPainter>
#include <QtStateMachine/QFinalState>
#include <QtStateMachine/QStateMachine>
#include <QtWidgets/QApplication>
#include <QtWidgets/QVBoxLayout>
#include <QtWidgets/QWidget>
//! [0]
class LightWidget : public QWidget
{
Q_OBJECT
Q_PROPERTY(bool on READ isOn WRITE setOn)
public:
explicit LightWidget(const QColor &color, QWidget *parent = nullptr)
: QWidget(parent), m_color(color)
{
}
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:
void paintEvent(QPaintEvent *) override
{
if (!m_on)
return;
QPainter painter(this);
painter.setRenderHint(QPainter::Antialiasing);
painter.setBrush(m_color);
painter.drawEllipse(rect());
}
private:
QColor m_color;
bool m_on = false;
};
//! [0]
//! [1]
class TrafficLightWidget : public QWidget
{
Q_OBJECT
public:
explicit TrafficLightWidget(QWidget *parent = nullptr) : QWidget(parent)
{
auto 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);
auto pal = palette();
pal.setColor(QPalette::Window, 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;
};
//! [1]
//! [2]
QState *createLightState(LightWidget *light, int duration, QState *parent = nullptr)
{
auto lightState = new QState(parent);
auto timer = new QTimer(lightState);
timer->setInterval(duration);
timer->setSingleShot(true);
auto timing = new QState(lightState);
QObject::connect(timing, &QAbstractState::entered, light, &LightWidget::turnOn);
QObject::connect(timing, &QAbstractState::entered, timer, QOverload<>::of(&QTimer::start));
QObject::connect(timing, &QAbstractState::exited, light, &LightWidget::turnOff);
auto done = new QFinalState(lightState);
timing->addTransition(timer, &QTimer::timeout, done);
lightState->setInitialState(timing);
return lightState;
}
//! [2]
//! [3]
class TrafficLight : public QWidget
{
Q_OBJECT
public:
explicit TrafficLight(QWidget *parent = nullptr) : QWidget(parent)
{
auto vbox = new QVBoxLayout(this);
auto widget = new TrafficLightWidget;
vbox->addWidget(widget);
vbox->setContentsMargins(QMargins());
auto machine = new QStateMachine(this);
auto redGoingYellow = createLightState(widget->redLight(), 3000);
redGoingYellow->setObjectName("redGoingYellow");
auto yellowGoingGreen = createLightState(widget->yellowLight(), 1000);
yellowGoingGreen->setObjectName("yellowGoingGreen");
redGoingYellow->addTransition(redGoingYellow, &QState::finished, yellowGoingGreen);
auto greenGoingYellow = createLightState(widget->greenLight(), 3000);
greenGoingYellow->setObjectName("greenGoingYellow");
yellowGoingGreen->addTransition(yellowGoingGreen, &QState::finished, greenGoingYellow);
auto yellowGoingRed = createLightState(widget->yellowLight(), 1000);
yellowGoingRed->setObjectName("yellowGoingRed");
greenGoingYellow->addTransition(greenGoingYellow, &QState::finished, yellowGoingRed);
yellowGoingRed->addTransition(yellowGoingRed, &QState::finished, redGoingYellow);
machine->addState(redGoingYellow);
machine->addState(yellowGoingGreen);
machine->addState(greenGoingYellow);
machine->addState(yellowGoingRed);
machine->setInitialState(redGoingYellow);
machine->start();
}
};
//! [3]
//! [4]
int main(int argc, char **argv)
{
QApplication app(argc, argv);
TrafficLight widget;
widget.resize(110, 300);
widget.show();
return app.exec();
}
//! [4]
#include "main.moc"
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