pyqt5 show which button was clicked

Question

I am new to PyQT5 and I want to have several buttons and have the one clicked last in a "checked" state. When another button is clicked the previous one gets "unchecked" while the clicked one gets "checked".

import sys
from PyQt5.QtWidgets import *

class Example(QWidget):
    def __init__(self):
        super().__init__()
        self.setGeometry(30, 30, 400, 200)
        self.initUI()

    def initUI(self):
        self.button1 = QPushButton(self)
        self.button1.setGeometry(40, 40, 100, 50)
        self.button1.setText("Button 1")

        self.button2 = QPushButton(self)
        self.button2.setGeometry(150, 40, 100, 50)
        self.button2.setText("Button 2")

        self.show()

if __name__ == '__main__':
    app = QApplication(sys.argv)
    ex = Example()
    sys.exit(app.exec_())

Answer 1

You can use functools partial or the sender method to check which button was pressed:

import sys
from PyQt5.QtWidgets import *
from functools import partial
class Example(QWidget):
    def __init__(self):
        super().__init__()
        self.setGeometry(30, 30, 400, 200)
        self.initUI()

    def initUI(self):
        self.button1 = QPushButton(self)
        self.button1.setGeometry(40, 40, 100, 50)
        self.button1.setText("Button 1")
        self.button1.clicked.connect(partial(self.clicked_btn, 'Button 1'))

        self.button2 = QPushButton(self)
        self.button2.setGeometry(150, 40, 100, 50)
        self.button2.setText("Button 2")
        self.button2.clicked.connect(partial(self.clicked_btn, 'Button 2'))

        self.show()

    def clicked_btn(self, value):
        print(f'{value} clicked')
        sender = self.sender()
        print(f'Sender says: {sender.text()} was clicked')

if __name__ == '__main__':
    app = QApplication(sys.argv)
    ex = Example()
    sys.exit(app.exec_())

Answer 2

Building off of your code, you can add button1 and button2 to a QButtonGroup with the exclusive property set to True.

class Example(QWidget):
    def __init__(self):
        super().__init__()
        self.setGeometry(30, 30, 400, 200)
        self.initUI()

    def initUI(self):
        self.button1 = QPushButton(self)
        self.button1.setGeometry(40, 40, 100, 50)
        self.button1.setText("Button 1")

        self.button2 = QPushButton(self)
        self.button2.setGeometry(150, 40, 100, 50)
        self.button2.setText("Button 2")

        self.btn_grp = QButtonGroup()
        self.btn_grp.setExclusive(True)
        self.btn_grp.addButton(self.button1)
        self.btn_grp.addButton(self.button2)

        self.btn_grp.buttonClicked.connect(self.on_click)

        self.show()

    def on_click(self, btn):
        pass # do something with the button clicked

if __name__ == '__main__':
    app = QApplication(sys.argv)
    ex = Example()
    sys.exit(app.exec_())

Here I've also connected an empty slot to the signal QButtonGroup.buttonClicked, which is emitted whenever a button from the group is clicked.

To find out which button is the currently checked button, you can invoke the methods QButtonGroup.checkedButton() and QButtonGroup.checkedId(). The former will return a QButton object and the latter will return an index int, corresponding to the order in which the buttons were added to the group.