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50
51 #include <QApplication>
52 #include <QFinalState>
53 #include <QPainter>
54 #include <QStateMachine>
55 #include <QTimer>
56 #include <QVBoxLayout>
57 #include <QWidget>
58
59 //! [0]
60 class LightWidget : public QWidget
61 {
62 Q_OBJECT
63 Q_PROPERTY(bool on READ isOn WRITE setOn)
64 public:
LightWidget(const QColor & color,QWidget * parent=nullptr)65 LightWidget(const QColor &color, QWidget *parent = nullptr)
66 : QWidget(parent), m_color(color), m_on(false) {}
67
isOn() const68 bool isOn() const
69 { return m_on; }
setOn(bool on)70 void setOn(bool on)
71 {
72 if (on == m_on)
73 return;
74 m_on = on;
75 update();
76 }
77
78 public slots:
turnOff()79 void turnOff() { setOn(false); }
turnOn()80 void turnOn() { setOn(true); }
81
82 protected:
paintEvent(QPaintEvent *)83 void paintEvent(QPaintEvent *) override
84 {
85 if (!m_on)
86 return;
87 QPainter painter(this);
88 painter.setRenderHint(QPainter::Antialiasing);
89 painter.setBrush(m_color);
90 painter.drawEllipse(0, 0, width(), height());
91 }
92
93 private:
94 QColor m_color;
95 bool m_on;
96 };
97 //! [0]
98
99 //! [1]
100 class TrafficLightWidget : public QWidget
101 {
102 public:
TrafficLightWidget(QWidget * parent=nullptr)103 TrafficLightWidget(QWidget *parent = nullptr)
104 : QWidget(parent)
105 {
106 QVBoxLayout *vbox = new QVBoxLayout(this);
107 m_red = new LightWidget(Qt::red);
108 vbox->addWidget(m_red);
109 m_yellow = new LightWidget(Qt::yellow);
110 vbox->addWidget(m_yellow);
111 m_green = new LightWidget(Qt::green);
112 vbox->addWidget(m_green);
113 QPalette pal = palette();
114 pal.setColor(QPalette::Window, Qt::black);
115 setPalette(pal);
116 setAutoFillBackground(true);
117 }
118
redLight() const119 LightWidget *redLight() const
120 { return m_red; }
yellowLight() const121 LightWidget *yellowLight() const
122 { return m_yellow; }
greenLight() const123 LightWidget *greenLight() const
124 { return m_green; }
125
126 private:
127 LightWidget *m_red;
128 LightWidget *m_yellow;
129 LightWidget *m_green;
130 };
131 //! [1]
132
133 //! [2]
createLightState(LightWidget * light,int duration,QState * parent=nullptr)134 QState *createLightState(LightWidget *light, int duration, QState *parent = nullptr)
135 {
136 QState *lightState = new QState(parent);
137 QTimer *timer = new QTimer(lightState);
138 timer->setInterval(duration);
139 timer->setSingleShot(true);
140 QState *timing = new QState(lightState);
141 QObject::connect(timing, &QAbstractState::entered, light, &LightWidget::turnOn);
142 QObject::connect(timing, &QAbstractState::entered, timer, QOverload<>::of(&QTimer::start));
143 QObject::connect(timing, &QAbstractState::exited, light, &LightWidget::turnOff);
144 QFinalState *done = new QFinalState(lightState);
145 timing->addTransition(timer, &QTimer::timeout, done);
146 lightState->setInitialState(timing);
147 return lightState;
148 }
149 //! [2]
150
151 //! [3]
152 class TrafficLight : public QWidget
153 {
154 public:
TrafficLight(QWidget * parent=nullptr)155 TrafficLight(QWidget *parent = nullptr)
156 : QWidget(parent)
157 {
158 QVBoxLayout *vbox = new QVBoxLayout(this);
159 TrafficLightWidget *widget = new TrafficLightWidget;
160 vbox->addWidget(widget);
161 vbox->setContentsMargins(QMargins());
162
163 QStateMachine *machine = new QStateMachine(this);
164 QState *redGoingYellow = createLightState(widget->redLight(), 3000);
165 redGoingYellow->setObjectName("redGoingYellow");
166 QState *yellowGoingGreen = createLightState(widget->yellowLight(), 1000);
167 yellowGoingGreen->setObjectName("yellowGoingGreen");
168 redGoingYellow->addTransition(redGoingYellow, &QState::finished, yellowGoingGreen);
169 QState *greenGoingYellow = createLightState(widget->greenLight(), 3000);
170 greenGoingYellow->setObjectName("greenGoingYellow");
171 yellowGoingGreen->addTransition(yellowGoingGreen, &QState::finished, greenGoingYellow);
172 QState *yellowGoingRed = createLightState(widget->yellowLight(), 1000);
173 yellowGoingRed->setObjectName("yellowGoingRed");
174 greenGoingYellow->addTransition(greenGoingYellow, &QState::finished, yellowGoingRed);
175 yellowGoingRed->addTransition(yellowGoingRed, &QState::finished, redGoingYellow);
176
177 machine->addState(redGoingYellow);
178 machine->addState(yellowGoingGreen);
179 machine->addState(greenGoingYellow);
180 machine->addState(yellowGoingRed);
181 machine->setInitialState(redGoingYellow);
182 machine->start();
183 }
184 };
185 //! [3]
186
187 //! [4]
main(int argc,char ** argv)188 int main(int argc, char **argv)
189 {
190 QApplication app(argc, argv);
191
192 TrafficLight widget;
193 widget.resize(110, 300);
194 widget.show();
195
196 return app.exec();
197 }
198 //! [4]
199
200 #include "main.moc"
201