Button Clicked
-----------------

.. code-block:: python
   :caption: scripts/PYQT2/01_main_widget/04_button_click/main.py
   :linenos:

   from PyQt5.QtWidgets import QMainWindow, QApplication, QPushButton, QLabel

   class MainWindow(QMainWindow, object):
       def __init__(self, parent=None):
           super(MainWindow, self).__init__(parent)
           
           self.init_ui()
           
       def init_ui(self):
           self.button = QPushButton("Click Me!", self)
           self.label = QLabel("Button not clicked.", self)
           
           self.button.move(50, 20)
           self.button.clicked.connect(self.on_button_click)
           
           self.label.move(50, 60)
           
       def on_button_click(self):
           self.label.setText("Button clicked!")
           
   if __name__ == "__main__":
       app = QApplication([])
       mainWindow = MainWindow()
       mainWindow.show()
       app.exec_()

- This example connects a click event to the button to change the label's text.
- The ``clicked.connect()`` method is used to connect the method to be executed on button click (the ``on_button_click`` function).