Question

python tkinter 不显示窗口

from tkinter import *

def main():
tk = Tk()
canvas = Canvas(tk, width = 400, height = 400)
canvas.pack()
def moverectangle(event):
if event.keysym == 'Up':
canvas.move(1, 0, -5)
elif event.keysym == 'Down':
canvas.move(1, 0, 5)
elif event.keysym == 'Left':
canvas.move(1, -5, 0)
elif event.keysym == 'Right':
canvas.move(1, 5, 0)

canvas.create_rectangle(10, 10, 50, 50, fill = 'red')
canvas.bind_all('<KeyPress-Up>', moverectangle)
canvas.bind_all('<KeyPress-Down>', moverectangle)
canvas.bind_all('<KeyPress-Left>', moverectangle)
canvas.bind_all('<KeyPress-Right>', moverectangle)

if __name__ == '__main__':
main()

Answer 1

在main函数第一行加上
global tk,canvas
tk,canvas必须是全局变量 ,在函数外才能使用,
然后在main函数最后加一行
tk.mainloop()
只有调用Tk对象的mainloop方法才能显示窗口

追问

额 窗口出来了 可是创建的长方形不见了。。。