State machines in Qt 6

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

How to do it…

A 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:

Figure 3.5 – Setting up the GUI for our state machine experiment

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();

4. We will define what we should do within each state, which, in this case, will be to change the label’s text and the...