Files:
The Two-way button example shows how to use The State Machine Framework to implement a simple state machine that toggles the current state when a button is clicked.
int main(int argc, char **argv) { QApplication app(argc, argv); QPushButton button; QStateMachine machine;
The application's main() function begins by constructing the application object, a button and a state machine.
QState *off = new QState(); off->assignProperty(&button, "text", "Off"); off->setObjectName("off"); QState *on = new QState(); on->setObjectName("on"); on->assignProperty(&button, "text", "On");
The state machine has two states; on and off. When either state is entered, the text of the button will be set accordingly.
off->addTransition(&button, SIGNAL(clicked()), on); on->addTransition(&button, SIGNAL(clicked()), off);
When the state machine is in the off state and the button is clicked, it will transition to the on state; when the state machine is in the on state and the button is clicked, it will transition to the off state.
machine.addState(off); machine.addState(on);
The states are added to the state machine; they become top-level (sibling) states.
machine.setInitialState(off); machine.start();
The initial state is off; this is the state the state machine will immediately transition to once the state machine is started.
#if defined(Q_OS_SYMBIAN) button.showMaximized(); #elif defined(Q_WS_MAEMO_5) || defined(Q_WS_SIMULATOR) button.show(); #else button.resize(100, 50); button.show(); #endif return app.exec(); }
Finally, the button is resized and made visible, and the application event loop is entered.