1

我需要访问类内部的全局对象来更改它的图像。这是代码：

import pygame
from livewires import games
from livewires import color
import time
import random

games.init(screen_width = 640, screen_height = 480, fps = 50)

class Cursor(games.Sprite):
    """The pokemon based cursor!"""

    def __init__(self, image, x ,y):
        super().__init__(image=image, x=x, y=y)



    def update(self):


        self.x = games.mouse.x
        self.y = games.mouse.y   
        self.check_collide()

    def check_collide(self):
        for sprite in self.overlapping_sprites:
            sprite.handle_collide()



class Play_Button(games.Sprite):
    """The 'Play' button on the menu."""

    def __init__(self , image, x ,y):
        super().__init__(image=image, x=x, y=y)

    def handle_collide(self):
        global play_obj

        play_image2 = games.load_image("playbtn2.png", transparent = True)
        play_obj.value = play_image2
        print("COME ON!")


class P1C_Button(games.Sprite):

    def __init__(self, image, x, y):
        super().__init__(image=image, x=x, y=y)

class Logo(games.Sprite):

    def handle_collide(self):
        print("Collision ignored.")



play_image = games.load_image("playbtn.png", transparent = True)
play_obj = Play_Button(image = play_image,
                x = games.screen.width/2,
                y = games.screen.height/2)
games.screen.add(play_obj)


logo_image = games.load_image("FamilyMon.png", transparent = True)
logo_obj = Logo(image = logo_image,
                x = games.screen.width/2,
                y = 75)
games.screen.add(logo_obj)

white_image = games.load_image("white.png", transparent = False)
games.screen.background = white_image

cursor_image = games.load_image("cursor.png", transparent = True)
cursor_obj = Cursor(image = cursor_image,
                    x = games.mouse.x,
                    y = games.mouse.y)
games.screen.add(cursor_obj)
games.mouse.is_visible = False
games.screen.event_grab = True

games.screen.mainloop()

其中重要的部分是在“Play_Button”的 handle_collide 方法中。它试图访问创建的对象“play_obj”，但代码似乎什么也没做。当鼠标套 Play_Button 的 handle_collide 什么都没有。我在这里已经尽力了，所以如果这看起来是一个愚蠢的问题而不是抱歉，因为我是新手。

4

2 回答 2

2

我试图理解为什么以下列方式这样做不能满足你

def handle_collide(self):
    play_image2 = games.load_image("playbtn2.png", transparent = True)
    self.value = play_image2
    print("COME ON!")

...

据我所知，只有一个Play_Button实例，您想在collide发生时更改其图像。

那么，为什么不使用self.value呢？

于 2015-06-14T21:44:01.407 回答
2

首先，您不应该使用全局变量。

您只创建一个Play_Button对象，因此全局play_obj always is self。您可以让该对象设置自己的字段：

self.value = play_image2
于 2015-06-14T21:53:36.723 回答