examples/widgets/state-machine/eventtrans

(You can also check this code in the repository)

eventtrans.py

import sys

from PySide6.QtCore import QEvent, QRect, Qt
from PySide6.QtWidgets import QApplication, QMainWindow, QPushButton
from PySide6.QtStateMachine import QEventTransition, QState, QStateMachine


class MainWindow(QMainWindow):
    def __init__(self):
        super().__init__()
        button = QPushButton(self)
        button.setGeometry(QRect(100, 100, 100, 100))

        machine = QStateMachine(self)
        s1 = QState()
        s1.assignProperty(button, 'text', 'Outside')
        s2 = QState()
        s2.assignProperty(button, 'text', 'Inside')

        enter_transition = QEventTransition(button, QEvent.Enter)
        enter_transition.setTargetState(s2)
        s1.addTransition(enter_transition)

        leave_transition = QEventTransition(button, QEvent.Leave)
        leave_transition.setTargetState(s1)
        s2.addTransition(leave_transition)

        s3 = QState()
        s3.assignProperty(button, 'text', 'Pressing...')

        press_transition = QEventTransition(button, QEvent.MouseButtonPress)
        press_transition.setTargetState(s3)
        s2.addTransition(press_transition)

        release_transition = QEventTransition(button, QEvent.MouseButtonRelease)
        release_transition.setTargetState(s2)
        s3.addTransition(release_transition)

        machine.addState(s1)
        machine.addState(s2)
        machine.addState(s3)

        machine.setInitialState(s1)
        machine.start()

        self.setCentralWidget(button)
        self.show()


if __name__ == '__main__':
    app = QApplication(sys.argv)
    main_win = MainWindow()
    sys.exit(app.exec())