python打砖块

import pygame
from pygame.locals import *
import time
import random
import sys
import os
pygame.init()

canvas = pygame.display.set_mode((1000,625))

pygame.display.set_caption("打砖块")
class Ball(pygame.sprite.Sprite):
    def __init__(self):
        pygame.sprite.Sprite.__init__(self)
        self.image=pygame.image.load("ball.png")
        self.image=pygame.transform.scale(self.image,(50,50))
        self.rect=self.image.get_rect()
        position=[100,100]
        self.rect.center=position
        self.speed=[-1,-1]
    def xianshi(self):
        canvas.blit(self.image,self.rect)
    def move(self):
        self.rect=self.rect.move(self.speed)
    def hit(self):
            if self.rect.top<=0 :
                self.speed[1]=-self.speed[1]
                self.rect=self.rect.move(self.speed)
            if self.rect.left<=0 or self.rect.right>=1000:
                self.speed[0]=-self.speed[0]
                self.rect=self.rect.move(self.speed)

class Enemy(pygame.sprite.Sprite):
    def __init__(self,pos):
        pygame.sprite.Sprite.__init__(self)
        self.image=pygame.image.load("enemy.png")
        self.image=pygame.transform.scale(self.image,(50,30))
        self.rect=self.image.get_rect()
        self.rect.center=pos
    def xianshi(self):
        canvas.blit(self.image,self.rect)
    def move(self):
        self.rect=self.rect.move(self.speed)
bj=pygame.sprite.Group()
banlist=[(50,50),(150,50),(250,50),(350,50),(450,50),(550,50),(650,50),(750,50),(850,50),(950,50),
(50,100),(150,100),(250,100) , (350,100),(450,100),(550,100),(650,100),(750,100),(850,100),(950,100),
(50,150),(150,150),(250,150) , (350,150),(450,150),(550,150),(650,150),(750,150),(850,150),(950,150),
(50,200),(150,200),(250,200) , (350,200),(450,200),(550,200),(650,200),(750,200),(850,200),(950,200),
(50,250),(150,250),(250,250) , (350,250),(450,250),(550,250),(650,250),(750,250),(850,250),(950,250),
  ]
for i in range(50):
    enemy = Enemy(banlist[i])
    bj.add(enemy)
class Ban(pygame.sprite.Sprite):
    def __init__(self):
        pygame.sprite.Sprite.__init__(self)
        self.image=pygame.image.load("1.png")
        self.image=pygame.transform.scale(self.image,(200,20))
        self.rect=self.image.get_rect()
        self.rect.center=(500,610)
    def xianshi(self):
        canvas.blit(self.image,self.rect)
ban=Ban()


def handleEvent():
    for event in pygame.event.get():
        if event.type == QUIT :
            pygame.quit()
            sys.exit()
ball=Ball()
score=0
lenl = 0
while True:
    canvas.fill((255, 255, 255))
    ball.xianshi()
    ball.move()
    ball.hit()
    ban.xianshi()
    for e in bj:
        e.xianshi()
    keys=pygame.key.get_pressed()
    if keys[K_LEFT]:
        ban.rect.left -= 2
        if ban.rect.left <= 0:
            ban .rect.left = 0
    if keys[K_RIGHT]:
        ban.rect.left += 2
        if ban.rect.right >= 1000:
            ban.rect.right = 1000

    if pygame.sprite.collide_rect(ball,ban):
        ball.speed[1] = random.randint(-2,-1)
        lenl +=1
    if pygame.sprite.spritecollide(ball,bj,1):
        score+=1
    font = pygame.font.SysFont("kaiti", 40)
    text = font.render("分数：" +str(score)+"能量"+str(lenl),True,(0,0,0))
    canvas.blit(text, (0,0))
    handleEvent()
    pygame.display.update()