main.cpp Example File

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  #include <QtCore>
  #include <stdio.h>

  class PingEvent : public QEvent
  {
  public:
      PingEvent() : QEvent(QEvent::Type(QEvent::User+2))
          {}
  };

  class PongEvent : public QEvent
  {
  public:
      PongEvent() : QEvent(QEvent::Type(QEvent::User+3))
          {}
  };

  class Pinger : public QState
  {
  public:
      Pinger(QState *parent)
          : QState(parent) {}

  protected:
      void onEntry(QEvent *) override
      {
          machine()->postEvent(new PingEvent());
          fprintf(stdout, "ping?\n");
      }
  };

  class PongTransition : public QAbstractTransition
  {
  public:
      PongTransition() {}

  protected:
      bool eventTest(QEvent *e) override {
          return (e->type() == QEvent::User+3);
      }
      void onTransition(QEvent *) override
      {
          machine()->postDelayedEvent(new PingEvent(), 500);
          fprintf(stdout, "ping?\n");
      }
  };

  class PingTransition : public QAbstractTransition
  {
  public:
      PingTransition() {}

  protected:
      bool eventTest(QEvent *e) override {
          return (e->type() == QEvent::User+2);
      }
      void onTransition(QEvent *) override
      {
          machine()->postDelayedEvent(new PongEvent(), 500);
          fprintf(stdout, "pong!\n");
      }
  };

  int main(int argc, char **argv)
  {
      QCoreApplication app(argc, argv);

      QStateMachine machine;
      QState *group = new QState(QState::ParallelStates);
      group->setObjectName("group");

      Pinger *pinger = new Pinger(group);
      pinger->setObjectName("pinger");
      pinger->addTransition(new PongTransition());

      QState *ponger = new QState(group);
      ponger->setObjectName("ponger");
      ponger->addTransition(new PingTransition());

      machine.addState(group);
      machine.setInitialState(group);
      machine.start();

      return app.exec();
  }