I'm trying to simulate an American traffic light, with 3 circles on a rectangle, all drawn on a set Canvas. The simulation is supposed to mirror "animation" by changing which light is displayed every 2 seconds in the following order: green > yellow > red > green, etc forever.
The only way I can think of to do this is by using a canvas.move(), canvas.after(), canvas.update() pattern to move a filled oval object to superimpose one unfilled circle at a time. I've gotten the logic down to move a circle at the proper speed and in the correct order. The thing is, I just instantiate a circle filled with "green", but I can't change it to be "yellow" or "red" using this method. It seems silly to have to canvas.delete("filled") and redraw it in a new place with a different fill every 2 seconds, because that's a lot to do for such a simple program.
Question 1: Is there a way I can just alter the fill option for my filled Canvas object at will, using some method or other means?
Question 2: Am I approaching this scenario incorrectly? Is there a better way to simulate this?
Yes you should be able to change settings of the canvas with config.
Likewise, use itemconfig to change items on the canvas. This does require that you save a handle to the item or tag them.
Example from tkinterbook:
i = w.create_line(xy, fill="red")
w.coords(i, new_xy) # change coordinates
w.itemconfig(i, fill="blue") # change color
来源：https://stackoverflow.com/questions/12991717/can-you-change-the-attributes-of-a-canvas-object-after-creation