State machines in Qt

A state machines can be used for many purposes but, in this chapter, we will only cover topics related to animation.

How to do it...

State machine is not that hard to achieve in Qt at all. Let's get started by following these steps:

1. We will set up a new user interface for our example program, which looks like this:

2. We will include some headers in our source code:

#include <QStateMachine>
#include <QPropertyAnimation>
#include <QEventTransition>

3. In our main window's constructor, add the following code to create a new state machine and two states, which we will be using later:

QStateMachine *machine = new QStateMachine(this);
QState *s1 = new QState();
QState *s2 = new QState...