Qt 5.11 | Qt Widgets | Ping Pong States Example | main.cpp Example File

Qt 5.11.3 Reference Documentation

# main.cpp Example File

statemachine/pingpong/main.cpp

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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();
      }