main.cpp Example File | Qt Widgets 5.12.8

Qt 5.12 | Qt Widgets | Ping Pong States Example | main.cpp Example File

Qt 5.12.8 Reference Documentation

# main.cpp Example File

statemachine/pingpong/main.cpp

      /****************************************************************************
      **
      ** Copyright (C) 2016 The Qt Company Ltd.
      ** Contact: https://www.qt.io/licensing/
      **
      ** This file is part of the QtCore module of the Qt Toolkit.
      **
      ** $QT_BEGIN_LICENSE:BSD$
      ** Commercial License Usage
      ** Licensees holding valid commercial Qt licenses may use this file in
      ** accordance with the commercial license agreement provided with the
      ** Software or, alternatively, in accordance with the terms contained in
      ** a written agreement between you and The Qt Company. For licensing terms
      ** and conditions see https://www.qt.io/terms-conditions. For further
      ** information use the contact form at https://www.qt.io/contact-us.
      **
      ** BSD License Usage
      ** Alternatively, you may use this file under the terms of the BSD license
      ** as follows:
      **
      ** "Redistribution and use in source and binary forms, with or without
      ** modification, are permitted provided that the following conditions are
      ** met:
      **   * Redistributions of source code must retain the above copyright
      **     notice, this list of conditions and the following disclaimer.
      **   * Redistributions in binary form must reproduce the above copyright
      **     notice, this list of conditions and the following disclaimer in
      **     the documentation and/or other materials provided with the
      **     distribution.
      **   * Neither the name of The Qt Company Ltd nor the names of its
      **     contributors may be used to endorse or promote products derived
      **     from this software without specific prior written permission.
      **
      **
      ** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
      ** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
      ** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
      ** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
      ** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
      ** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
      ** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
      ** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
      ** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
      ** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
      ** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
      **
      ** $QT_END_LICENSE$
      **
      ****************************************************************************/

      #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();
      }