Do not run the event on Tkinter

Question

Do not run the event on Tkinter

Navigation

#1 by (1 votes)

1

I have a problem with Tkinter to execute the movement of the polygon with the arrows of the cursor, it does not generate an error, but it is not executed either.

My code is:

from tkinter import *
tk = Tk()
canvas = Canvas(tk, width=400, height=400)
canvas.pack()
canvas.create_polygon(10,10,10,60,50,35)
def movertriangulo(evento):
    if event.keysym == 'Up':
        canvas.move(1,0,-3)
    elif event.keysym == 'Down':
        canvas.move(1,0,3)
    elif event.keysym == 'Left':
        canvas.move(1,-3,0)
    elif event.keysym == 'Right':
        canvas.move(1,3,0)


canvas.bind_all('Up',movertriangulo)
canvas.bind_all('Down',movertriangulo)
canvas.bind_all('Left',movertriangulo)
canvas.bind_all('Right',movertriangulo)

I appreciate guidance. Thanks.

python python-3.x

asked by Jsierra2017 14.04.2017 в 19:22

source

1 answer

First time running a sample program [closed] render in a different context in react?

score 1 · Accepted Answer

We go in parts:

First of all you are specifying the event badly, the name of the event must be between angle brackets:
```
'<Up>'
```
You can see the correct syntax in the Tkinter documentation .
To the function movertriangulo you define it like this: def movertriangulo(evento) but inside it you use the parameter event no evento , you must correct this.
This is not an error in itself but if a very bad practice , you import the module in the form:
```
 from tkinter import *
```
This is dangerous and should never be done. You can find unpleasant surprises and difficult to find bugs, especially with extensive codes and complex libraries. Use some of these formulas instead:
```
import tkinter
from tkinter import Tk, Camvas
import tkinter as tk
```
You do not start the mainloop of your application, if you use the IDLE it runs correctly because the IDLE itself uses Tkinter, so it has its own mainloop. If you launch it from the console or from another side that is not the IDLE, the application will not start.

The code would look like this:

import tkinter as tk

root = tk.Tk()
canvas = tk.Canvas(root, width=400, height=400)
canvas.pack()
canvas.create_polygon(10,10,10,60,50,35)

def movertriangulo(event):
    if event.keysym == 'Up':
        canvas.move(1,0,-3)
    elif event.keysym == 'Down':
        canvas.move(1,0,3)
    elif event.keysym == 'Left':
        canvas.move(1,-3,0)
    elif event.keysym == 'Right':
        canvas.move(1,3,0)


canvas.bind_all('<Up>',movertriangulo)
canvas.bind_all('<Down>',movertriangulo)
canvas.bind_all('<Left>',movertriangulo)
canvas.bind_all('<Right>',movertriangulo)

root.mainloop()

Another option is to implement a function for each event:

import tkinter as tk

root = tk.Tk()
canvas = tk.Canvas(root, width=400, height=400)
canvas.pack()
canvas.create_polygon(10,10,10,60,50,35)

def izquierda(event):
    canvas.move(1,-3,0)

def derecha(event):
    canvas.move(1,3,0)

def abajo(event):
    canvas.move(1,0,3)

def arriba(event):
    canvas.move(1,0,-3)

canvas.bind_all('<Up>',arriba)
canvas.bind_all('<Down>',abajo)
canvas.bind_all('<Left>',izquierda)
canvas.bind_all('<Right>',derecha)

root.mainloop()