Binding Buttons to Callback Functions

[Edward Anderson]

I am attempting to generate buttons with loops in a py file and then display them in a kv file. Both files are attached.  When I rem out the py line labeled "Problem Child" it works as desired by displaying an array of 150 random color and random text buttons that change color when clicked. When "Problem Child" is not remmed out, no display appears. an error message is generated and the "SelectTile" callback prints the correct data for he first button only. How do I bind the same callback to all 150 buttons or bind a common callback to all buttons?

[Chisoul Munthali]

Check out this solution to address your issue you encountered, the source code is self-explanatory.

On Fri, 11 Apr 2025, 17:49 Edward Anderson, <edand...@gmail.com> wrote:

I am attempting to generate buttons with loops in a py file and then display them in a kv file. Both files are attached.  When I rem out the py line labeled "Problem Child" it works as desired by displaying an array of 150 random color and random text buttons that change color when clicked. When "Problem Child" is not remmed out, no display appears. an error message is generated and the "SelectTile" callback prints the correct data for he first button only. How do I bind the same callback to all 150 buttons or bind a common callback to all buttons?

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[ElliotG]

A more object orientated approach would be to recognize that a Tile is a Button, and you can create a specialized Button class, and use it as you would a Button, rather than creating a Utility class.

class TileStack(GridLayout):  # use a layout to hold the buttons
    TARGET = 0
    N_ROWS = 10
    N_COLS = 15

    def __init__(self, **kwargs):
        super().__init__(**kwargs)
        TARGET = random.randint(0, 9) + random.randint(0, 9)
        print(TARGET)
        for i in range(0, self.N_ROWS):
            for j in range(0, self.N_COLS):
                rand_int1 = random.randint(100, 254) / 255
                rand_int2 = random.randint(100, 254) / 255
                rand_int3 = random.randint(100, 254) / 255
                rand_int4 = random.randint(0, 9)
                my_color = (rand_int1, rand_int2, rand_int3, 1)
                my_id = str(i) + '-' + str(j) + '-' + str(rand_int4)
                self.add_widget(Tile(my_id, my_color, rand_int4))    # instance a Tile and add to the Layout 


class Tile(Button):  # a Tile is a Button
    def __init__(self, my_id, my_color, my_value, **kwargs):
        super().__init__(**kwargs)
        self.text = str(my_value)
        self.font_size = 32
        self.bold = True  # use True not a string "true"
        self.color = (0, 0, 0, 1)
        self.background_normal = ""
        self.background_color = my_color
        self.tile_id = my_id              
        self.bind(on_press=self.selected)

    def selected(self, obj):
        print(f"selected {self.tile_id}")  # self refers to this instance of the button

[Edward Anderson]

Thank you all. Elliot's solution wass exactly what I was attempting to accomplish!

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