Why is the animation not working? The shape doesn't move when I run the program.
from Tkinter import *
import time
class alien(object):
def __init__(self):
self.root = Tk()
self.canvas = Canvas(self.root, width=400, height = 400)
self.canvas.pack()
alien1 = self.canvas.create_oval(20, 260, 120, 360, outline='white', fill='blue')
alien2 = self.canvas.create_oval(2, 2, 40, 40, outline='white', fill='red')
self.canvas.pack()
self.root.mainloop()
def animation(self):
track = 0
while True:
x = 5
y = 0
if track == 0:
for i in range(0,51):
self.time.sleep(0.025)
self.canvas.move(alien1, x, y)
self.canvas.move(alien2, x, y)
self.canvas.update()
track = 1
print "check"
else:
for i in range(0,51):
self.time.sleep(0.025)
self.canvas.move(alien1, -x, y)
self.canvas.move(alien2, -x, y)
self.canvas.update()
track = 0
print track
alien()
You never called the animation method. There were a couple of other naming issues.
# Assuming Python 2.x
# For Python 3.x support change print -> print(..) and Tkinter to tkinter
from Tkinter import *
import time
class alien(object):
def __init__(self):
self.root = Tk()
self.canvas = Canvas(self.root, width=400, height = 400)
self.canvas.pack()
self.alien1 = self.canvas.create_oval(20, 260, 120, 360, outline='white', fill='blue')
self.alien2 = self.canvas.create_oval(2, 2, 40, 40, outline='white', fill='red')
self.canvas.pack()
self.root.after(0, self.animation)
self.root.mainloop()
def animation(self):
track = 0
while True:
x = 5
y = 0
if track == 0:
for i in range(0,51):
time.sleep(0.025)
self.canvas.move(self.alien1, x, y)
self.canvas.move(self.alien2, x, y)
self.canvas.update()
track = 1
print "check"
else:
for i in range(0,51):
time.sleep(0.025)
self.canvas.move(self.alien1, -x, y)
self.canvas.move(self.alien2, -x, y)
self.canvas.update()
track = 0
print track
alien()
Your animation method has a while True loop in it which never breaks. This is a no-no in a GUI program, because by never returning, it prevents the GUI's event-loop from processing events. So, for example, if you had a Menu, then the user would not be able to select any menu item. The GUI would appear frozen, except for whatever actions you implement in the animation method.
Here is a slight modification of @Tim's code which fixes this problem by removing the while loop and simply moving the aliens one step before returning. self.master.after is called at the end of the animation method to have the event loop call animation again after a short pause.
import tkinter as tk
import time
class Alien(object):
def __init__(self, canvas, *args, **kwargs):
self.canvas = canvas
self.id = canvas.create_oval(*args, **kwargs)
self.vx = 5
self.vy = 0
def move(self):
x1, y1, x2, y2 = self.canvas.bbox(self.id)
if x2 > 400:
self.vx = -5
if x1 < 0:
self.vx = 5
self.canvas.move(self.id, self.vx, self.vy)
class App(object):
def __init__(self, master, **kwargs):
self.master = master
self.canvas = tk.Canvas(self.master, width=400, height=400)
self.canvas.pack()
self.aliens = [
Alien(self.canvas, 20, 260, 120, 360,
outline='white', fill='blue'),
Alien(self.canvas, 2, 2, 40, 40, outline='white', fill='red'),
]
self.canvas.pack()
self.master.after(0, self.animation)
def animation(self):
for alien in self.aliens:
alien.move()
self.master.after(12, self.animation)
root = tk.Tk()
app = App(root)
root.mainloop()
Here's a way of doing it using a loop:
from tkinter import * # version 3.x
tk = Tk()
frame = Frame(tk)
canvas = Canvas(frame) # use canvas
frame.pack(fill = BOTH, expand = 1)
canvas.pack(fill = BOTH, expand = 1)
ball = canvas.create_oval(10, 10, 30, 30, tags = 'ball') # create object to animate
def animation(x_move, y_move):
canvas.move(ball, x_move, y_move) # movement
canvas.update()
canvas.after(20) # milliseconds in wait time, this is 50 fps
tk.after_idle(animation, x_move, y_move) # loop variables and animation, these are updatable variables
animation(2, 2) # run animation
An updatable variable is a variable that stays the same when updated and can be updated again.
