How to bind spacebar key to a certain method in tkinter (python)

Question

I am working on a project in python, and I made a method to draw a specific thing in tkinter. I want it so that whenever I press the spacebar, the image will redraw itself (run the method again because I coded the method so that it could redraw over itself). How exactly would I bind the spacebar to the method so that the program would run, draw, and re-draw if I pressed the spacebar?

for example, i want it so that whenever I press space, the program draws in a random location on the canvas:

from Tkinter import *
from random import *

root=Tk()
canvas=Canvas(root,width=400,height=300,bg='white')
def draw():
    canvas.delete(ALL)# clear canvas first
    canvas.create_oval(randint(0,399),randint(0,299),15,15,fill='red')
draw()
canvas.pack()
root.mainloop()

how would i bind the spacebar to the method?

Solution 1

from Tkinter import *
from random import *

root=Tk()
canvas=Canvas(root,width=400,height=300,bg='white')
def draw(event=None):
    canvas.delete(ALL)# clear canvas first
    canvas.create_oval(randint(0,399),randint(0,299),15,15,fill='red')
draw()
canvas.pack()

root.bind("<space>", draw)
root.mainloop()

Solution 2

You could do something like this:

from Tkinter import *
from random import *

root=Tk()
canvas=Canvas(root,width=400,height=300,bg='white')

def draw(event):
    if event.char == ' ':
        canvas.delete(ALL)# clear canvas first
        canvas.create_oval(randint(0,399),randint(0,299),15,15,fill='red')

root.bind('<Key>', draw)

canvas.pack()
root.mainloop()

Basically, you bind your drawing function to some top-level element to the <Key> binding which is triggered whenever a key on the keyboard is pressed. Then, the event object that's passed in has a char member which contains a string representing the key that was pressed on the keyboard.

The event will only be triggered when the object it's bound to has focus, which is why I'm binding the draw method to the root object, since that'll always be in focus.