python for kids 14章弹球游戏代码及其编程小测验4个问题的实现

代码如下：

from tkinter import *
import tkinter
import tkinter.messagebox
import random
import time

def callbackClose():
    tk.destroy()

class Ball:
    def __init__(self,canvas,paddle,color):
        self.canvas = canvas
        self.paddle = paddle
        self.id = canvas.create_oval(10,10,25,25,fill=color)
        self.canvas.move(self.id,245,100)
        starts = [-3,-2,-1,0,1,2,3]
        random.shuffle(starts)
        self.x = starts[0]
        self.y = -1
        self.canvas_height = self.canvas.winfo_height()
        self.canvas_width = self.canvas.winfo_width()
        self.hit_bottom = False
        self.score = 0
        
    def hit_paddle(self,pos):
        paddle_pos = self.canvas.coords(self.paddle.id)
        if pos[2] >= paddle_pos[0] and pos[0] <= paddle_pos[2]:
            if pos[3] >= paddle_pos[1] and pos[1]<= paddle_pos[3]:
                self.score += 1
                return True
        return False

    def draw(self):
        self.canvas.move(self.id,self.x,self.y)
        pos = self.canvas.coords(self.id)
        if pos[1] <= 0:
            self.y = random.randint(1,3)
        if pos[3] >= self.canvas_height:
            self.hit_bottom = True
        if pos[0] <= 0:
            self.x = random.randint(1,3)
        if pos[2] >= self.canvas_width:
            self.x = -random.randint(1,3)
        if self.hit_paddle(pos)==True:
            self.y = -3
            self.x -= paddle.x

class Paddle:
    def __init__(self,canvas,color):
        self.canvas = canvas
        self.id = canvas.create_rectangle(0,0,100,10,fill=color)
        self.canvas.move(self.id,200,300)
        self.x = 0
        self.startFlag = False
        self.canvas_width = self.canvas.winfo_width()
        self.canvas.bind_all('',self.turn_left)
        self.canvas.bind_all('',self.turn_right)
        self.canvas.bind_all('',self.startMy)
    def turn_left(self,evt):
        self.x = -2
    def turn_right(self,evt):
        self.x = 2
    def draw(self):
        self.canvas.move(self.id,self.x,0)
        pos = self.canvas.coords(self.id)
        if pos[0]< 0:
            self.x = 0
        if pos[2]> self.canvas_width:
            self.x = 0
    def startMy(self,evt):
            self.startFlag = True


class ScoreBoard:
    def __init__(self,canvas,ball):
        self.canvas = canvas
        self.id = canvas.create_text(200,20,text='Score Board.')
    def draw(self):
        message = "Your Score:" + str(ball.score)
        canvas.itemconfig(self.id,text=message)
    def draw_game_over(self):
        canvas.itemconfig(self.id,text='Game Over.')
    def get_ready(self):
        canvas.itemconfig(self.id,text='Click the left button to start the Game.')


tk = Tk()
tk.title("PaddleBall")
tk.resizable(0,0)
tk.wm_attributes("-topmost",1)
tk.protocol("WM_DELETE_WINDOW",callbackClose)
canvas = Canvas(tk,width=500,height=400,bd=0,highlightthickness=0)
canvas.pack()
tk.update()
paddle = Paddle(canvas,'blue')
ball = Ball(canvas,paddle,'red')
scoreboard = ScoreBoard(canvas,ball)


def initialization():
    global paddle,ball,scoreboard
    paddle = Paddle(canvas,'blue')
    ball = Ball(canvas,paddle,'red')
    scoreboard = ScoreBoard(canvas,ball)

while True:
    if paddle.startFlag == False:
        scoreboard.get_ready()
    if ball.hit_bottom == False and paddle.startFlag == True:
        ball.draw()
        paddle.draw()
        scoreboard.draw()
    elif ball.hit_bottom == True:
        time.sleep(1)
        scoreboard.draw_game_over()
    tk.update_idletasks()
    tk.update()
    time.sleep(0.01)