PyQt Signals let you react to user input such as mouse clicks. A slot is a function that gets called when such an event occurs. The file main.py in this directory shows this in action: When the user clicks a button, a popup appears:
The code begins in the usual way. First, we import PyQt5 and create a QApplication:
from PyQt5.QtWidgets import *
app = QApplication([])
Next, we create a button:
button = QPushButton('Click')
Then we define a function. It will be called when the user clicks the button. You can see that it shows an alert:
def on_button_clicked():
alert = QMessageBox()
alert.setText('You clicked the button!')
alert.exec_()
And here is where signals and slots come into play: We instruct Qt to invoke our function by connecting it to the .clicked signal of our button:
button.clicked.connect(on_button_clicked)
Finally, we show the button on the screen and hand control over to Qt:
button.show()
app.exec_()
For instructions how you can run this example yourself, please see here.