Connect arrays of buttons in QT Designer

Question

so I have a mass of buttons on a QT Designer GUI application all named LED_i where i ranges from 0-191, ie: LED_0, LED_1, ..., LED_191. I would like basically the same thing to happen when clicked except changing the input i. So LED_0 when clicked would call the function OnClick(0), LED_75 would call OnClick(75) etc etc.

I am connecting my buttons with

ui.LED_0.clicked.connect(OnClick0)

usually using a separate function for each button. However this would require 191 functions, and 191 lines like the above connecting my buttons to their functions. I'm sure I could edit it s.t. I can use the same function by passing the button name that was clicked and getting the number from it but that would still require the 191 lines of button.clicked.connect. Is there any way to do this more efficiently?

TIA

Answer 1

It's not impossible with PyQt5. This is a good fit for a QButtonGroup. And there are a few ways to approach it.

QButtonGroup using Designer

To set up a QButtonGroup in Designer, do the following:

• select two or more buttons, radioboxes, or checkboxes
• right click on one of the buttons and you'll get a context menu item, Assign to button group --> New button group

After this, you'll see buttonGroup (the default name) show up in the Object Inspector.

To run code when one of your buttons is clicked, you can use the buttonClicked signal of QButtonGroup. It will give you a reference to the button that was clicked, and from the objectName, you can figure out what to do.

ui.buttonGroup.buttonClicked.connect(self.OnClicked)

then

def OnClicked(self, button):
     # button objectName follows pattern LED_<number>
     button_number = int(button.objectName()[4:])
     ... do stuff here with button_number

QButtonGroup in code

In the original post, there were 191 buttons in Designer. That is a lot of buttons to arrange. If for some reason, you wanted to do it in code instead, you could assign each button an id as it is added to the group and then you could use the idClicked signal:

grid = QGridLayout()
buttonGroup = QButtonGroup()
buttonGroup.idClicked.connect(OnClick)
buttonList = []
for row in range(14):
    rowList = []
    for col in range(14):
        button_number = 14*row + col
        button = QPushButton(f'{button_number}', objectName=f'LED_{button_number}')
        rowList.append(button)
        buttonGroup.addButton(button, button_number)
        grid.addWidget(button, row, col)

then

def OnClick(self, idClicked):
    ... do something with idClicked here