Keyboard and Mouse Input Detection
----------------------------------

PyQt allows you to detect and handle keyboard and mouse events simultaneously. In this example, the on-screen message changes when the user presses the 'A' key and then clicks the mouse.

.. code-block:: python

    import sys
    from PyQt5.QtWidgets import QApplication, QMainWindow, QLabel, QVBoxLayout, QWidget
    from PyQt5.QtCore import Qt

    class CombinedEventApp(QMainWindow):
        def __init__(self):
            super(CombinedEventApp, self).__init__()
            self.key_pressed = None
            self.a_clicked = False
            self.label = QLabel("Press 'A' and then click the mouse!", self)
            self.label.setAlignment(Qt.AlignCenter)

            layout = QVBoxLayout()
            layout.addWidget(self.label)

            container = QWidget()
            container.setLayout(layout)
            self.setCentralWidget(container)

            self.init_ui()

        def init_ui(self):
            self.setWindowTitle('Combined Keyboard and Mouse Event')
            self.setGeometry(100, 100, 400, 300)

        def keyPressEvent(self, event):
            if event.key() == Qt.Key_A:
                if not self.a_clicked:
                    self.key_pressed = Qt.Key_A
                    self.a_clicked = True
                else:
                    self.key_pressed = None
                    self.a_clicked = False
            else:
                self.key_pressed = None
                self.a_clicked = False

        def mousePressEvent(self, event):
            if self.key_pressed == Qt.Key_A:
                self.label.setText("You pressed 'A' and clicked the mouse!")
                self.key_pressed = None
            else:
                self.label.setText("Press 'A' and then click the mouse!")
            self.a_clicked = False

Explanation:
------------

The key components of this example are the ``keyPressEvent`` and ``mousePressEvent`` functions:

- ``keyPressEvent``: This function detects keyboard events, changing the label's text when the 'A' key is pressed.

- ``mousePressEvent``: Detects mouse events. If the 'A' key is pressed when the mouse is clicked, the label's text changes again.

Through these two functions, the behavior of simultaneously detecting and handling keyboard and mouse inputs is implemented.